NATIONAL BUREAU OF STANDARDS REPORT

9921

Progress Report

on THE CRYSTAL STRUCTURES OF GAYLUSSITE, CaNa (COj^ SH-O

AND PIRSSONITE, CaNaJCO ) -2H 0

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
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NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

31 1.05-1 1-3 1 1056 1 June 30, 1968 9921

Progress Report

on THE CRYSTAL STRUCTURES OF GAYLUSSITE, CaNa^COj) -5^0

AND PIRSSONITE, CaNaJCO-L'ZH 0

by

Brian Dickens* and Walter E. Brown

+

* Research Chemist, Dental Research Section, National Bureau

of Standards, Washington, D. C. 20234.

+ Director, Research Associate Program of the American Dental

Association, Dental Research Section, National Bureau of

Standards, Washington, D. C. 20234

This investigation is part of the dental research program

conducted by the National Bureau of Standards, in cooperation with the Council on Dental Research of the American

Dental Association; the National Institute for Dental Research; the Dental Research Division of the U. S. Army Medical Research and Development Command; the Dental Sciences

Division of the School of Aerospace Medicine, USAF; and the

Veterans Administration.

IMPORTANT NOTICE NATIONAL BUREAU OF STA

for use within the Government. I and review. For this reason, the whole or in part, is not authorij Bureau of Standards, Washingtor

the Report has been specifically f

Approved for public release by the

Director of the National Institute of

Standards and Technology (NIST) on October 9, 2015

s accounting documents intended objected to additional evaluation

listing of this Report, either in

Office of the Director, National

r the Government agency for which

pies for its own use.

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

- 1 -

The Crystal Structures of Gaylussite, CaNa2 (CO^ ) 2

* 5H20

and Pirssonite, CaNa2 (CO^

)

2

*2 h

20

Brian Dickens and Walter E. Brown

Abstract

The crystal structure of synthetic gaylussite has been determined from single-crystal x-ray diffraction data. The unit cell is

a = 14.361 ± .002, b = 7-781 ± .004, c = 11.209 ± .002a, 6 = 127.84 ±

.01°, and the space group is C2/c . R^ = (S(wj|Fj -| F

c

ll ) 2

)/S(w| F | ) 2 = 0.043, R = 0.054. The hydrogen atoms have been located. Two CO-^

anions are coordinated to a Ca ion and form a dihedral angle of

134.3°. Each CO^ group is coordinated to four Na ions and four water

molecules, but to only one Ca ion. Each Na is coordinated to four CO

groups and two water molecules. Two water molecules form hydrogen

bonds to neighboring CO^ anions. The remaining water forms hydrogen

bonds with the oxygens of two other water molecules

.

The crystal structure of synthetic pirssonite has also been

determined from single-crystal x-ray diffraction data. The unit cell

is a = 11.340 ± .004, b = 20.096 ± .005, £

= 6.034 ± .002a and the

space group is Fdd2. R^ = 0.029, R = 0.044. The hydrogen atoms

have been located. As in gaylussite, two CO^ anions are coordinated

to a Ca ion but with a dihedral angle of 95.5°. In contrast to

gaylussite, the CO^ anions are also coordinated to a second Ca ion,

as well as to four Na ions and two water molecules. Each Na ion is

coordinated to four CO^ anions and loosely to two water molecules.

The water molecules complete the coordination of Ca ions and form

hydrogen bonds with neighboring CO^ anions.
- 2 -

INTRODUCTION

In our studies1 of hydrated salts which have potential

importance in biological mineralization, the crystal

synthetic synthetic

structures of/ gay lus site8

, CaNa2 (C03 ) 2

• 5H2 0, ancj/pirs sonite3

,

CaNa2 (C03 ) 3

• 2H2 O, have been determined and are reported here.

Work on both these structures was completed before that of

Corazza and Sabelli4 on pirssonite came to our attention.

Determination of the Structure of Gaylussite

Crystals of gaylussite were grown in beakers containing

100 ml water, 18 g Na2 C03 , 10 g CaCl 2 and 800 ppm of sodium

polyphosphate, combining the procedures of Bury and Redd5

and Brooks, Clark and Thurston. 6 The initial solid phase

was mostly spherulites, probably of CaC03 -H2 0 or vaterite.

On standing, these dissolved and good single crystals of

gaylussite were formed.
-3-

A single crystal of gaylussite about 0.2 mm in crosssection (u Mo = 9 cm-1

) was sealed in a borate glass capillary

to prevent slow dehydration. The cell dimensions* were

refined from 25 20 values observed on a diffractometer7 to

a = 14.361 ± .002, b = 7.781 ± .001, c = 11.209 ± .002 K,

3 = 127.84 ± .01°, assuming \(Mo Kccj ; a3 ) = 0.71069 A, for

the cell with space group C2/c or Cc and z = 4. The most

obvious cell is body centered, with axial ratios which

correspond to those given in Dana® The space groups C2/c

and Cc were chosen using the convention adopted in the

International Tables for Crystallography^

The intensities of reflections in a hemisphere of the

reciprocal lattice were measured on a diffractometer7 using

Mo-Ka radiation, an 0.001 inch Nb filter; and the peak-height

method. The peak-to-intensity curve was established from 48

suitable reflections, spread uniformly over the 29 range.

*The uncertainties quoted on cell dimensions are standard

errors computed from least squares refinements of the cell

dimensions to fit observed 20 values.
-4-

which were measured both by peak heights and by scanning.

The data were merged into 2988 unique reflections, of which

2632 were of observable intensity. Since serious errors in

peak height measurements are usually caused by measuring

the background too near an adjacent peak, by slight misalignment of the crystal, or by absorption, in all of which

cases the observed would be too small, any supposedly

genuine and equivalent values of which were not within

10 % of one another were not averaged. Instead, the larger

of the two was taken as the observed . The discrepancy

value, S ||

4 | - j F /

\\/T, |

t | , between reflections accepted as

equivalent was 0.045, based on F's. (Although the anisotropy

of the mosaic spread of the crystal affects the peak

heights, in this case the peak height method provided data

of sufficient accuracy Q ) No corrections for absorption

were made.

The subsequent calculations were all performed using

the crystallographic computing system (X-ray 63) assembled

under the editorship of J. M. Stewart at the University of

Maryland. The quasi-unitary structure factors 9 (^| E

2 |^made

equal to 1) indicate (see Table 1) that the space group is
TABLE 1

Quasi-Unitary Structure Factor Statistics for Gaylussite

<^ | e | /> (|e2 |^ ^|e3 -i|^

All reflections .816 1.000 .922

3-dimensional .803 .957 .887

reflections only

Theoretical , centric .798 1.000 .968

Theoretical, acentric .886 1.000 .736

obs

.

centric acentric

Fraction of E

1 s > 1.0 .341 .317 .368

2.0 . 0366 .046 .018

3.0 .0009 .003 .0001

Number of reflections 2988

Suggested overall temperature factor 1.28
-6-

centr©symmetric, C2/c, instead of non-centrosymmetr ic, Cc.

This choice was subsequently verified by the structure

determination* The atomic scattering factors used were taken

from reference 10, except for those of hydrogen, which were

taken from reference 11. The quantity R w =

Z(w||f 0 |- |f c ||

2 was minimized in the full matrix least

squares refinements using a weighting scheme based on the

counting statistics.

The structure was solved from the sharpened Patterson

function, calculated from the (E 2 -l) coefficients, and from

subsequent F0 Fourier syntheses. It was refined isotropically

to R w = 0*079 allowing the scale factor, the positional parameters and the thermal parameters to vary. The structure

was then refined anisotropically to R w = 0.061. The hydrogens

were located from a difference synthesis® Inclusion of

O these hydrogens with fixed thermal parameters (B H = 1.0AS

)

in the refinement decreased R w to 0.043. The observed

and calculated structure factors are given in Table 2.
7

TABLE 2

Observed and Calculated Structure Factors

Columns are l, 10F0 , 10FC for Gaylussite

2 483 -4 42

4 922 437

4 434 477

• 413 413

10 121 123

12 484 474

14 181 -181

14 244 227 2.0.1

-14 37 37 -14 144 -173 -12 114 123 -10 143 -203

-8 810 870

-4 384 -621

-4 1742 1734

-2 344 -374

0 644 432

2 207 212

4 67 73

8 324 323

10 182 -202

12 403 400

14 77 -44 4.0 .

-16 26 • 32 -14 118 -110 -12 201 203 -10 1113 -1173

-8 375 403 -6 781 -828

-4 87 -110

-2 389 -344

0 513 -442

2 1281 -1189

« 446 434

6 774 -793

8 343 336

10 129 -134

12 87 -81

-18 307 -291 -14 226 202 -14 411 -413

10 271 -

123 124

308 -330 -13

-10 139 -133

81 114 116

4 123 -124

132 -143

300 -241

218 -221

179 183

79 83 224 -227

81 -72

268 -260

177 -173

175 -174

132 140

165 158

72 -67

257 -246

-19 148 -133

20 42 10

19 116 -104

18 24» -7

17 159 lfrl -16 24« 0 -13 176 -184

-14 147 -139

-13 47 36 -12 21* 4 -11 100 -113

-10 446 -440

-9 78 86 -8 20» 14 -7 397 -408

-6 67 68

-5 189 192

-4 21 • -6

-3 324 -329 -2 80 -108

-1 91 90

0 162 -179

1 229 -240

2 83 -77

3 80 85

4 182 168

3 93 -108

17.1 .L 20 29« -31

19 28» -13

18 275 -253

17 159 172

16 237 228

13 61 45

14 67 -73

13 321 345

12 99 -102

11 109 -106 ' 10 97 89 -9 J 72 384 -8 236 -234

-7 31 -35

-6 206 -223

-3 303 318

0 237 -236

-19 136 -128

-16 276 -276 -1 -13 141 -146

195 -192 -10 175

-9 137 -153

-8 51 56

-7 378 -622

-4 237 -244

-3 1532 -1434

-2 1872 1798

380 374

3 430 -421

-9 215 233

233 -248 -I

56 -10 283

4 263 -251

230 238

46 -63 227 -233

134 -132 -17 220 146 -142 -14 40

44 -43 -13 133

738 734 -13

326 -343

4.3.1

-18 100 109 -17 26 • -4 -16 187 -169 -15 151 130 -14 102 -79 -IS 249 -243

-12 418 -396

-11 182 176 -10 241 -240

-9 19 • IS -8 308 -314

-7 47 47

-6 237 234

-5 119 -118

-4 470 -476

-3 30 -72

-2 149 -171

-l 37 74

0 432 -433

1 172 146

2 19. 6

3 322 -313

4 171 -181

3 266 240

6 247 231

7 71 -48

8 113 -122

9 27 • 2 10 61 31

-1 204 -

14.

.

-19 29. 23

-18 82 86 -17 43 -40

-14 220 -2 27 -15 76 -64

-14 42 -15

-13 106 -123

-12 128 -130

-11 24. 23 -10 180 188

-9 123 -134

-8 112 -116

-7 38 24 -6 115 123 -3 277 -288

-4 218 -239

-3 114 116

-2 109 121

-1 36 -60

0 60 -52

1 32 -53

301 247

830 838

437 473

-17 207 -141

-14 39 -37

-13 233 229

-14 74 59 -13 316 -293

-12 31 -15

-11 70 82 -10 136 138 -9 308 -313

-8 33 -32

-7 204 200 -6 429 -433

-3 499 -502

-4 217 233 -3 443 417

-2 223 -226

-1 483 -489

0 68 62

1 483 684

2 378 388

3 478 -402

4 307 -311

3 306 298

6 163 -14 C

7 47 -39

8 103 112

9 203 203

10 80 -47

11 109 - U 7 12 74 63

-12 56 56 -10 164 -141 -8 229 -233 -6 2008 -1888

-4 217 -244

-2 1570 -1498

0 238 234

2 1283 -1232

4 105 -108

6 621 -399

8 23* -24

10 285 -273

12 128 133 8.0.L

-18 133 -122 -16 163 167 -14 229 -244 -12 108 113 -10 224 -236

-8 255 267

-6 569 -611

-4 870 874 -2 2054 -1989

0 79 80

2 184 -161

4 39 -24

6 379 -356

0 89 84

10 383 -371 10.0,1

-10 430 -

•IS 148 -146 -16 90

203 207

104 -199

-10 71 -74

300 310

73 -14 231 -227

-12 709 714 -10 130 -119

-8 419 420

-6 103 -102

-4 609 603 -2 78 100

71 79

302 -504

302 -367

333 -934

404 379

783 665

630 -648

327 414

-18 164 133 -17 124 124 -16 219 203 -13 103 -98

-14 229 -209

-13 76 92 -12 249 259

-11 109 -119

-10 30 -21

-9 419 436

-6 36 7 -7 200 -200

-4 373 392 -3 472 465

-4 303 271 -3 216 -216

-2 23 1 -1 357 352

0 18* -7

1 39 -39

2 328 -321

3 190 179

4 347 341

3 35 -23

6 38 37

7 186 191

8 25* -10

9 154 -161

10 43 -51

ll.l.L

19. -17

220 -203

640 -434

342 337

93 74 212 222

291 -277

108 -117

39 -77

590

-4 113 123 -3 102 -99

-2 157 -166 -1

163 176 -1

-19 28" -27

-18 28* 40 -17 234 263 -16 97 -87

-13 32 -35

-14 78 -99

-13 317 323 -12 125 132

-ll 23* 25 -10 62 61 -9 337 378

-8 81 79 -7 23* 11 -6 145 -138

-3 223 246

-4 77 82 -3 26. 34 -2 127 -137

-1 225 262

0 43 33

1 102 -103

21.1.L

-17 119 116 -16 123 134 -13 119 -125

-14 33 -26 -13 174 107

-12 128 120

-11 -77

613

223 -224

192 -191

222 218

73 -42

238 -238

83 75 133 148

-10 214 -218 -9 131 139 -8 179 200 -7 65 -67

-6 173 188 -3 230 232

2 623 -693

-107

-228 826

325 -329

399 400

904 905

353 349

210 220

113

144 -112

144 -157

110 103 317 327

313 -324

32 -27 447 436

632 610

156 -154

133 -146

-4 689 687

32 486

-11 333 -337

-10 126 123 -9 68 49 -8 68 78 -7 393 -391

-6 197 193 -3 158 133

-4 444 -464

-3 354 -368

-2 138 144 -1 46 -49

0 300 -398

1 126 -126

2 159 167

3 105 104

4 83 -84

3 204 -215

6 29. -9

16..

-20 138 -134

-19 93 -07

-18 82 73 -17 194 187 -16 25" 26 -15 103 -101

-14 237 209 -13 133 128 -12 232 -228

-11 249 -246

-10 286 292

-9 241 249

-8 So2 -317

-7 150 -155

-6 222 228

-5 31 -22

-4 59 72

-3 176 -183

-2 191 298

-1 133 133

0 194 -213

1 247 -260

98 104

81

0 244 -234

137 -149

898 803

610 604

99 -153

116 -114

3.3 .L -14 94 -93

-15 09 79 -14 307 289 -13 94 -103

-12 61 -73

-11 21« 4 -10 54 52 -9 110 -124

-8 332 334 -7 183 179 -6 539 382 -5 36 -10

-4 46 -31

-3 313 -314

-2 888 847

-1 516 -331

0 898 -926

1 727 739

2 137 164

3 443 -396

4 124 133

5 52 28

6 46 30

7 69 -65

8 128 -124

9 46 43

I !• 74 86

II S 3 -88

12 316 -303

13 27. 6 14 101 102

77 168 —16<

-17 162 136 -14 1*1 -190

-15 141 -141

160 134

241 -242

384 -393

147 171

434 -678

206 -203

-18 29. 18 -17 173 -147

-16 25* 36 -15 24. 6 -14 166 -169

-13 282 -276

-12 130 -127

-11 121 128 -10 19. 2 -9 361 -562

-8 172 162 -7 18* -17

-6 96 -75

-5 943 -999

-4 135 -171

-3 243 254

-2 194 -179

-1 774 -798

0 138 -169

1 39 -32

2 19. 8 3 388 -383

4 S 3 78

3 104 1 C 6 4 38 -19

7 332 -343

10 149 -14

147 -10 204 -

339 360

141 -397

477 -478

1448 1439

77 -70

331 338

3 570 -6

4 208 -214

-10 360 -

-6 233 - -4 231

-2 261 -

-20 76 70 -18 181 -180 -16 244 271

11 137 146

12 133 -114

13 US -123

14 49 32

-20 116 107

218 -200

26* -14

138 -127 -14

284 284

33 3 141 -133

344 342 402 -407

346 -374

240 -20

19- -39

78 -78

373 -383

110 103

189 -180 -1

-18 30 -20

-17 91 -93 -16 191 -143 -13 34 -34

-17 26*

-14 80 49 -13 37 33 -14 311 324 -13 233 -224 -12 90 -96

•11 336 333 -10 294 313 -9 133 -123

-8 139 140

-7 20 • -23 -6 399 412

79 70 49 S 3 -9 42 -2 904 9 li -I 44 -48

• 227 -229

-42 -19 142

11 201 -194

12 39 -32

19 248 237

-14 48

-9 196 -
-7aTABLE 2

(continued)

It. 4,

9 >00 *>114 4 eo -40

9 174 174

4 24* 0

7 104 -174 14,4,1 -19 149 197 -18 147 129 -17 179 -170

-16 90 -77 -19 194 190 -14 29* 0 -19 04 -41

-12 91 92 -11 969 900 -10 00 -72

-9 171 -109

-0 991 999 -7 420 496 -6 91 -41 -9 66 -61

—4 21 • 20 -9 974 960

-2 111 116

-1 107 -191

0 207 -207

1 389 370

2 117 118

9 114 -106

4 212 202

9 177 172

14. 4,

-19 89 85 -18 67 -71 -17 137 -141 -16 216 210 -19 194 199 -14 96 54 -13 264 -276

-12 29® 15 •11 161 160 -10 34 -22

-4 126 -127

-8 54 -54

-7 360 343 -6 163 190

441

140

-312 74 274

145

2fl3 10*

14?!*• 44

71 15425® IQ*

62

140

62 197

-27

91

-142

•16 79 -34

•15 27® 10

•14 109 -100 13 44 10

•12 30 30 11 79 91

•10 932 -969

-9 57 96

-8 237 269

-7 262 290 -6 360 -376

-9 150 170

-4 247 260

-3 99 62

-2 241 -260

-1 274 279

0 510 -527

1 274 280

2 116 -132

3 202 227

4 463 489

5 196 20 3 6 266 -308

7 21 ® -12

0 311 915

9 115 122

10 94 -106

11 90 29

12 56 42

13 20® 17

9 91 96

6 84® 9

7 104 -104

• 179 100

® 20® -29

11. 5,

2«® -31

27® -34

109 169

94 47

110 -114

23® -4

499 444

21® -C

90 -104

38 39 240 240

74 -72

47 -49

90 40 315 924

115 113

243 257

183 -105

349 347

21® -1 270 -200

57 -52

262 256

25® -9

97 -98

28® -6

08 92

13. 9,

-10 193 -170

-19 25® 37 -14 106 -109

-13 119 106 -12 149 144 -11 57 57 -10 251 -259

-9 21® 30 -0 219 231 -7 207 108 -6 146 -157

-5 49 -50

27® 10

114 -110

93 -96

220 232

64 46

27® -46

30 -28

127 192

27® -18

67 67

42 -0

211 234

29® -7

0 694 661

1 313 -330

2 85 63

3 249 253

4 418 418

3 104 -190

6 64 -63

7 302 289

8 147 133

9 132 -149

10 29® 10

11 104 101 12 311 204

13 89 -93

14 118 -113

-15 200 -172

-14 141 -123

-13 108 91 -12 91 86 -ll 247 -224

-10 287 -268

-9 41 91 -0 317 323 -7 394 -403

-6 103 104

-3 66 -56

-4 111 -108

-3 561 -595

-2 231 -227

-l 33 41 0 463 406

1 503 -543

2 160 -162

-3 333 343

-4 03 76

-3 218 -239

-2 233 -237

-1 946 577

0 63 60

1 113 -123

2 192 -103

3 263 262

4 127 132

3 24® -37

6 123 -110

7 114 119

8 70 62

9 56 -63

10. 6.

-17 137 122 -16 216 187 -15 67 -56

-14 97 -03

-13 07 94

-12 360 370

-11 93 -108

-10 96 -117

-9 330 349

-8 20® -7 -7 186 -194 -6 299 290

-3 492 500

-4 413 421 -3 69 -67

-2 143 -144

-1 247 245

0 330 336

1 21® 3

2 261 -259

3 254 262

4 193 191

3 25® -17

6 26® -0

7 207 205

0 29® 31 12.6,1

-10 136 -116

-17 34 64 -16 27® 35 -13 110 -115

70 168

109

116

10237

•180 -63

106

101 -30

•147

200

-11423

162

55 109

-140

22 . -15 55 -62 -14 42 -30

-13 43 41 -12 121 120 -11 167 -182

-10 111 -114

-9 179 186

-0 142 149

-7 144 -139

-6 29® -22

1.7.L

-14 47 28 -13 116 119 -12 26® -13

-l l 3o8 -270 -10 259 241 -9 101 107 -8 31 -17

-7 261 -248

-6 180 209

-3 170 -155

-4 217 -230

-3 132 -143

-2 144 146

-7 27® -31 -4 65 -30

-3 133 160 -4 124 -127 -3 244 224 -2 94 -93

-1 264 200

0 106 -193

1 47 -40

2 201 210

3 207 213

4 130 -171

9 130 -126

6 50 40

7 143 151

8 137 -133

9 94 -90

9. 7,1 -17 129 111 -16 63 -49

-13 170 -166

-14 25® 16 -13 160 157 -12 211 -211

-11 23® -3 -10 47 -39

-9 93 97 -8 199 -207

-7 104 101 -6 204 216 -5 275 285 -4 158 -169

-3 103 -107

-2 108 -111

-l 260 279

0 178 -165

1 22® -25

2 72 69

3 268 266

4 175 -171

5 49 -33

6 157 153

7 44 71

8 70 -74

11. 7.

-17 43 29 -16 74 -88 -19 64 -63

-I 14® -4 -2 109 101

-1 79 01 0 77 -75

19, -16 93 -99

-13 29® -33 -14 27® 2 •13 201 200

-12 60 -66

-11 26® 13 -10 75 86 -9 107 113 -8 54 -33 -7 27® 17 -6 107 101 -3 174 184 -4 201 -198

-3 96 -100

-15 30® -32 -14 30® -20 -13 29® 24 -12 104 -104

-ll 74 -71 -10 28® 11 -9 212 220

-6 144 -139

-7 113 -122 -6 109 109 0.0,

0 315 -314

1 66 -33

2 31 -13

3 100 -113

4 323 -314

3 89 69

6 61 88

7 45 24

8 402 -390

9 47 32

10

111 110

11 26® -19

12 83 -03

13 37 54

-14 09 -84

-15 29® -9

-14 42 45

-13 26® 10 -12 233 -237

-ll 94 69

-10 234 237

-9 98 -93

-8 180 -174

-7 190 196 -4 286 283

-3 59 -67

-4 166 -164

-3 129 -137

-2 145 144

-1 133 165

0 132 -132

1 44 43

2 355 359

3 64 -70

4 132 -139

3 64 63

6 269 264

7 107 -90

0 73 -73

10.

6,

L -16 132 -112

-13 41 41

-14 79 86

-13 175 -163

-12 167 -165

-11 40 32

-10 36 3 -9 24® |4

-8 404 -390

-7 140 -133

-6 210 218

-3 43 41 -4 264 -278

-3 35 20

-2 137 169

-1 161 -172

0 247 -238

1 40 40

2 24® 30

3 113 -103

4 196 -160

5 86 77

-14 29® 21 -13 29® 8 -12 136 -143

-11 196 160 -10 111 114 -9 69 -57

-0 148 -153

-7 71 58 -6 177 179

-3 29® 12

-12 36 46

-11 63 59 -10 71 -59

-9 25® -15

-8 36 -41

-7 206 191 -6 23® -27

-5 220 -215

-4 241 -245

-3 320 319 -2 153 -143

-1 159 -157

0 52 -49

1 269 238

2 128 -120

3 120 -122

4 37 -32

3 39 -28

6 156 -154

7 68 -73

8 139 -126

9 150 135

10 41 -28

11 178 -167

3,9,1. -13 104 -110

-12 27® -25

-11 182 164 -10 59 -58

-9 171 -15C

-8 83 66 -7 233 242

-6 98 92 -5 187 -188

-4 21® -2

-3 232 -246

-4 109 121 -3 343 339

-2 37 -12

-1 127 -131

0 89 94

1 243 296

2 73 -76

3 100 -112

4 29® -10 10.4.1

-19 124 110 -18 101 -89 -17 163 -172

-16 37 31 -13 62 63 -14 25® -31 -13 180 -183

-12 24® 23 -11 213 212 -10 231 231 -9 378 -303

-8 07 -90 -7 172 179 -6 178 -184

-3 207 -217

-4 133 130

-3 223 223

-2 70 -70

-1 133 -163

.» 0 69 78

1 102 111 20.4.1

-18 94 07 -17 134 -150

-16 97 -90

-13 197 206 -14 07 -09 -13 220 -230 -12 54 40 -11 143 163 -10 166 -170

-9 204 -213

-0 109 106

-7 139 1*9 -6 71 02 -3 202 -209

-4 103 -121 -3 33 34

-2 72 -74

-l 137 -146 22.4.1

-17 97 -09 -14 71 77

-17 29® -13

-16 109 117 -13 50 57

-14 109 -99

-13 62 -08

-12 113 133 -ll 22® 23 -10 360 -375

-9 32 10

-0 97 100 -7 89 -04

-6 317 -316

-3 136 128 -4 205 -206

-3 173 186

-2 17® 10 -l 17® -19

0 192 186

1 141 143

2 580 -384

3 34 -42

4 108 108

5 119 122

6 307 -310

7 137 134

8 260 270

9 48 -3

10 47 -33

11 29® 6 12 29® 42

72 213

61

173

23< 130

04

20!

160

01 333

244

31448 427

121 234

100

34 11292

169

74

42

-71

193 -33

158 -83

276 -164

100 -71 -369

-231

530 -46 -647

-123

237 -93

13

13 113 -92 -183

-74

47

-4 32 -0

-3 108 110 -2 239 -241

-1 04 82

0 224 229

1 45 44

2 04 -79

3 29® 33

4 213 201

9 42 -14

6 210 -216

19.

3,

L -10 183 -172

-17 41 17 -16 103 103 -13 25® 12 -14 242 -240

-13 90 -88

-12 228 -232

-11 147 132 -10 290 -317

-9 22® 26

-8 113 119 -7 50 50 -6 425 -429

-5 05 75 -4 121 119 -3 23® 27

-2 276 -269

-1 30 46

0 39 -36

1 64 74

2 217 -22

3 27® -14

4 106 107

17.

3,

L -10 207 -204

-17 OS -71 -16 49 60 -13 43 44 -14 133 -130

-13 24® -30

-12 112 129 -ll 73 -70

-10 232 -263

-9 43 -41

-8 112 -121

-7 23® 4 -6 374 -337

-3 23® 14 -4 221 223

-3 67 37 -2 *70 -271

-l 0» -02

0 *7® 14

1 67 91

3 1*4 130

4 532 531

5 434 -446

6 91 -86

7 21® -0

0 204 180

9 108 -174

10 37 -34

11 49 63

12 61 49

13 143 -141

-16 39 53 -13 113 -112

-14 99 -02 -13 23® 29 -12 24® -18

-11 253 -2 46 -10 289 -203

-9 103 100

-8 32 -10

-7 380 -380

-6 461 -402

-3 116 124 -4 220 220

-3 584 -614

-2 144 -155

-l 40 -43

0 91 -103

1 487 -510

2 561 -508

3 63 -39

4 241 248

3 309 -310

6 119 -120

7 68 74

0

106 100

9 333 -319

10 25® -26

11 65 63

12 20® 11

-14 23® 9 -13 257 233

-12 141 140 -11 204 -205

-10 33 -33

-9 201 196

-0 315 339

-7 154 -139

-6 202 -2 04

-5 123 125

-4 179 163

-3 53 -32

-2 21® 0 -l 216 226

0 307 304

1 160 -164

2 49 -54

3 225 2 32

4 61 63

5 167 -170

6 29® -37

14, 6.

-10 29® -7 -17 157 151 -16 76 -58 -13 195 -184

-14 178 -169

-13 101 99

-12 56 37 -11 63 -84 -10 232 -227

-9 00 87

-8 291 291 -7 205 -219

-6 268 -266

-3 120 124

-4 119 124

-3 311 -304

-2 24® -49

-l 203 210

0 104 -97

1 219 -223

2 26 ® -6

3 92 104

4 230 236

-10

210 -167

87 92

155 131 43 -39

129 -113

61 70 24® 1 173 -186

203 -290

171 186

-1 54 -42

0 158 161

1 144 -155

2 157 172

3 121 128

4 71 -71

5 409 -396

6 263 269

7 266 252

0 256 -237

9 62 -71

10 113 103

11 26® 46

12 40 30 13 29® 5

3.7,

-15 103 -158 -14 164 154 -13 73 56 -12 58 -66

-1 1 99 -94

-10 23® -17

-9 22® -1

-8 ' 50 44

-7 144 -136 -6 26b 256

-5 146 -129 -4 50 -49

-3 397 -370

-2 271 273

-1 74 01

0 410 -425

1 542 -566

2 166 162

3 112 131

4 55 63

5 142 -141

6 67 69

7 111 -124

6 85 -07

9 114 -105

10 99 90

1

1 33 35

12 149 -143

3,7.1

-13 40 28 -14 139 136 -13 76 79 -12 97 -90

-11 23® -28

-10 59 61 -9 127 123

-8 117 -129

-7 179 -173

-6 20® -I -3 416 433

-14 67 64 -13 40 -26

-12 24® 12 -ll 227 -234

-10 44 42

-9 73 82 -0 209 -220

-7 180 -205

-6 79 70 -3 103 100 -® 191 -192 -3 165 -130

-2 254 259

-l 136 139

0 71 -64

1 113 -133

2 44 -40

3 52 54

4 100 -92

5 53 -43

6 106 107

13.

7,

L -17 42 -3

-16 132 -132

-15 195 -192

-14 122 131 -13 46 54 -12 24® -12

-ll 200 -190

-10 133 137 -9 23® -31 -0 37 22 -7 323 -337

-6 163 161 -3 22® -16

-4 173 -177

-3 173 -181

-2 136 146

-1 34 -6

0 72 -74

1 163 -174

2 178 180

3 92 83

4 20® 16

5 130 -145

13.7.

L -17 05 77 -16 28® 37 -13 81 -91 -14 154 152 - 1 3 60 44 -12 172 -170

-11 162 -145

-10 137 144 -9 91 92

-14 94 92 -13 28® 12 -12 132 -133

-ll 30 60 -10 120 123

-9 55 -30

-8 109 -103

-7 22® 45 -6 274 261 -5 21® -23

-4 442 -437

-3 20® 9 -2 122 124

-1 40 -44

0 401 -414

1 97 96

2 113 124

3 71 77

4 222 -233

5 41 20

6 84 08

7 123 -119

8 339 -321

9 129 110

10 72 79

11 27® 9

12 191 -179 4,0,1

-14 241 231 -13 32 -64 -12 101 -86

-l l 40 26 -10 171 163 -9 78 62 -8 54 -60

-7 79 91 -4 340 933

-3 20® 30 -4 36 -63 -3 20® 30 -2 347 560

-l 31 -23

0 263 -282

1 138 143

2 204 219

3 109 -109

4 110 -110

3 116 121 6 200 193

7 84 73

8 84 -74

9 40 -42

10 139 130

11 29® -13

6 166 177

12.8,1

-16 207 -171

-13 20® -2

-14 133 121 -13 66 52 -12 118 -114

-11 167 -155

-10 90 114

-9 99 -105

-0 260 -269

-7 23® 20

-6 06 94

-3 168 -175

-4 391 -409

-3 86 84

-2 124 143

-1 143 -140

0 168 -171

1 25® -17

2 37 66

3 27® 5

4 198 -194

3 116 -108

14. 8,

-16 142 -110

-13 00 -58

-14 164 164 -13 102 -102

-12 192 -204

-11 92 99

-10 196 206

-9 105 -101

-0 47 -49

-7 47 39

-6 136 137

-5 133 -132

-4 207 -208

-3 64 -62 -2 150 154

-1 91 83

0 262 -261

1 64 -50

2 122 130

3 63 -50

-14 29® -34

-13 110 06 -14 219 213

-13 03 -73

-12 130 -136

-ll 73 66 -10 170 171

-9 23® -2

-3 193 187 -2 37 28

-l 21® -29

0 22® -33

1 76 75

2 153 -151

3 33 -30

4 112 114

5 253 254

6 25® 30

7 216 -218

8 60 -54

9 130 124

10 20® 12 5.9.L -14 106 102 -13 206 -192

-12 43 26 -11 70 70 -10 93 78 -9 246 -222

-8 00 66 -7 40 42

-6 52 -48

-5 32 -24

-4 243 241 -3 56 54 -2 165 163

-1 253 -262

0 58 50

1 264 260

2 142 147

3 222 -223

4 24® 3 5 153 140

6 25® -6

7 59 -33

6 117 114

9 109 93

-14 27® -1 -13 121 -121

-12 26® 16

-11 25® 23 -10 106 102 -9 145 -144

-0 13# 122 -7 23® 13 -4 22® 13 -5 375 -376

-4 64 60 -3 184 183 -2 36 53

-1 200 -194

0 116 107

1 84 76

-15 IT* 170 -14 60 -47

-13 135 -140

-12 26® -10

-ll 159 174 -to no -no

-9 79 -84 -8 53 -47

-7 102 121 -6 28® -2 -5 167 -105

-4 29® -14

1,5, t -15 29® 46 -14 224 -227 -19 63 39 -12 50 57 -11 74 44 -10 22® -27

-9 94 09 -8 182 197

-7 49 53 -6 *6* -280 -5 44 34 -4 96 80 -I >1* 949

10 144 -155

4,9,L

-18 29® 14 -17 27® 13 -14 269 252

-15 44 ->*

-14 47 22 -13 1*3 -124

-12 231 240

-11 92 27

-10 119 -140

-9 192 -136

-8 515 592

-7 34 -27

-4 232 244

-5 145 -159

-4 509 916

-3 200 -305

-2 254 -254

-I 62 -49

0 939 352

1 82 -81

2 01 -72

9 170 -170

4 in no

19, 9,

96 -61

20® -25

197 191 49 -42

149 -103

25® -27

*10 213

25* -79

101 -0

47 233 247

29® 12

102 -106

134 -129

24® -27

24o -*

119 -128

29® 27

104 207

-2 949 -503

-1 142 149

0 20® 16

1 314 -320

2 20® -13

9 206 214

4 199 -190

9 319 -339

6 937 -341

7 140 158

9 142 139

9 136 -119

10 147 -139

11 49 50 0.4,1 -IT 130 120 -14 103 159 -15 159 -140

-14 179 -174

-13 230 225

-12 00 77 -ll 46 -30 -10 43 -36

-7 243 240

-0 357 360

-0 45 -45

-7 260 -266

-6 03 -95

-5 233 231 -4 79 79

-3 260 -251

-2 202 -202

-1 26® -0

0 94 07

1 92 -86

2 147 -152

-4 208 -210

-3 312 -296

-2 344 357

-1 40 31

0 139 -147

1 20® -28

2 30 50

3 02 -03

4 222 -224

3 148 -151

6 23® -13

7 119 137

3 37 -0

-IT

-16

-15

-14

-13

-12

-11 -10

70 111

121 143 20249

209

88

150

23« 147 290

30 14S

92 103 -127

-146

212

00 -214

72 138

-aa -136 -287

34 143

10 90 02

11 60 66 7,7,1

-13 27® -19

-14 43 -38

-13 226 223

-12 190 -186

-11 43 -62

-10 231 248 -9 309 393 -8 294 -238

-7 130 -132

-4 160 163 -5 35 29

-4 43 -3

-3 244 -230

-2 143 131 -l 57 48

0 81 -100

1 91 -94

2 99 93

3 29® 21 17,7,1 -17 182 156 -16 28® -29

-15 28® -32

-14 141 141 -13 133 134 -12 26® -20

-ll 42 -43

-10 162 170 -9 150 158 -8 169 -185 -7 7$ -79

-4 55 44 -5 135 147 -4 82 81

6,8,1

-15 49 45 -14 194 183 -13 73 55 -12 98 -95

-11 60 66 -10 349 360 -9 23® 1 -8 104 -113

-7 21® »9 -4 257 267

-5 90 9 -4 20® -14 -3 267 284

-2 431 446

-1 72 -86

0 31 -23

1 21® 9

2 492 490

3 89 91

4 130 -129

5 24# -35

6 186 101

7 26® 4

0 28® -49

9 63 69

147 -149

41 -28

216 219

141 142 26® -21

26® 7 174 173

120 -121

163 -172

113 124

185 175

184 -176

68 47

75 65

40 27

90 -00

75 60

-15 20® -14 94 -15 83 02.

-14 104 81

-11 56 -29

-10 229 234

-9 61 57

-8 143 -174

-7 109 114

-6 127 143 -5 91 -90

-4 127 -135

-3 13# 139 -2 170 165

164

25«

C4 187

108

172

35

89 202

24< 82
7b

TABLE 2

' (continued)

-10

252 21

1 •X) -6 26* 2 13) 1)

9) -9

118 205

60

- 30 -112

203

-10

159 115

1 50

87

196

- 11 * -194

-81 10T

6 *

7 • - 107 -10

66 -5

17.9.1 14 29* 22 I) 155 -152 12 27» 7 -II 21* 29

-10 91 79

-9 141 -143

-9 59 -55

-7 49 59

-6 40 -20

-5 194 -176

-4 9) 84 -3 164 164 -2 45 30

19. 9.

-12

-II -10

29* 25

84 82

57 4 1 254 -253

29* -1

86 90

29. 18

0,1

0 474 458

1 95 106

2 90 -97

3 176 -187

4 167 163

5 46 4)

* 24 • -22

7 49 -35

9 125 127

9 26* 16

10 30* -37

11 92 -81

-2 12) -124

-1 33 -14

0 169 17)

1 146 135

2 93 -99

3 59 5 )

4 292 292

5 89 79

* 52 -56

7 135 -133

9 61 70

9 127 119

10 77 -54

4.10.1

-12 69 72

-II 5) 74 -10 292 -243

-9 60 -69

-8 14? 142 -7 119 11) -6 197 -183

-5 23* -4

-4 120 124

-3 87 60 -2 109 -112

-1 55 -55

0 41 30

1 167 178

2 175 -179

3 105 -104

4 114 113

5 179 178

6 182 -172

7 2 ?• -10

8 190 195

9 43 40

6 . 10.1 -13 87 -71

-12 72 74 -11 25* -4

-10 100 -67

-9 129 -117

-6 40 60 -7 54 -47

-6 304 -29*

-5 168 -1)7

-4 55 50 -3 163 169

9.10.1 -1) 59 -59

-12 51 46 -11 40 3

-10 92 -68 -9 167 -172

-6 70 59

-7 93 101 -4 119 -120

-5 233 -229

-4 16) 162

-3 6) -5)

-2 369 -377

-1 70 -64

0 110 119

1 25* 21

2 92 -100

3 94 -67

4 2 7* 2)

5 26. 32

6 103 -91

10 . 10 ,

-14 96 -59

-1) 117 -110

-12 109 107

-ll 107 100 -10 168 -171 -9 56 -52 -8 16) 154 -7 50 46 -4 119 -119

-3 39 -27

-4 169 16) -3 36 37

-2 77 -69

-1 135 -123

0 131 114

1 69 64

2 142 -169

3 133 -129

4 64 74

12 . 10 .

-14 HI -106

-1) 91 57 -12 245 226

-11 62 56 -10 129 -124

2 105 -93

14.10.1

-I) 29. -26

-12 28* 27

-11 174 155 -10 74 -69

-9 27* -29

-9 194 199

-7 172 162

-4 79 -89

-5 70 -70

-4 115 119

-3 64 69

-2 127 -119

-I 65 51

0 132 149

14. 10.

-1) 135 -119

-12 60 57

-II 69 59 -10 97 -98

-9 53 -62

-8 103 101 -7 28* 21 -6 175 -169

-5 2 8* 12 -4 227 224

-3 73 37 18.10.1

-10 107 -102

-9 113 -115

-6 91 7) -7 46 40

1 , 11.1

-10 82 -77

-9 108 109

-9 118 109

-7 .99 -10)

-4 4) 35

-5 54 46

-4 36 25 -3 24. -27

-2 24. -0

-1 132 126

3,11,1.

-11 46 -22

-10 12) -109

-9 104 10)

-8 47 37 -7 23* -10

-4 57 -44 -5 12? 123

-4 24* 12 -3 112 -108

-2 87 -81

-1 173 172

0 90 96

1 71 -44

2 161 -176

3 159 130

4 139 139

5 26« -9

4 24* 2

7 80 71

9 43 39 3.11,t

-11 59 -34

-10 104 -97

-9 133 125

-8 26* -6

-7 110 -86

-6 267 -250

-3 216 205

-4 10? 101 -3 39 -3)

-2 134 -124

-1 76 68

0 80 -70

1 53 -41

2 85 -75

3 94 95

4 41 -20

5 59 -42

6 1)7 -1)9

7 130 130 7.U.L

-12 30 44

-11 92 -59

-10 69 -56

-9 91 94

-8 10? 91

4 27* -7

5 112 -113

9 , 11 ,

-12 116 86

-11 51 -34

-10 28* -2 -9 27* 44

-6 35 47

-7 100 -69

-4 44 29 -3 97 92 -4 141 142 -3 192 -19) -2 95 -94

-l 88 84 0 79 76

1 110 -100

2

110 -100

3 50 *4

11 . 11.1 -12 16) 1)3 -11 164 -156

-li 54 -44

-9 74 71 -8 90 89 -7 159 -146

-6 39 20 -3 74 71 -4 139 114 -3 76 -74

-2 26« -4

-1 27* -12

0 174 169

1 96 -65

2 46 -49

13,11,1. -12 6) 50 -11 10 ) -83

-10 57 -3)

-9 41 3) -8 149 1)7 -7 99 -63

-6 112 -102 -5 27* -9

-4 52 45 -3 7) -70

-4 80 74

0 , 12,1

-1 7? 70

0 30* 20

1 82 -70

2 26* 21

3 104 91

4 94 -92

5 150 -1)7

6 29* 14

7 187 184

9 53 -42

2.12.

L -9 74 76

-8 29 • -33

-7 120 -10?

-4 49 5) -3 50 -41

-4 88 -94

-3 164 -150

-2 23 • 14 -l 10? 107

0 65 -54

1 235 -219

2 26 • -16

3 145 146

4 40 37

5 191 -171

6 53 4)

7 51 37

4.12.

L -9 51 49

-8 28 • - 2 ) -7 127 -118

-4 26 • 3 -3 152 154 -4 26 • -9 -3 246 -230

-2 50 45

-l 72 74

0 100 -89

1 178 -167

2 5) 43

3 34 32

4 52 -51

3 94 -90

-3 44 -37

-2 107 105

-1 120 99

0 27* -33

1 79 -81

2 49 53

3 59 55

4 29* -19

9.12.1

-10 12) 99

-9 141 13)

-6 29* -*)

-7 27* -33

-4 113 119 -5 119 104 -4 39 24

-3 63 -64

-2 31 -43

-1 190 179

0 27* 21

1 8? -87

2 87 77

10 . 12 .

-10 53 31 -9 92 86

-6 26 • 3 -7 61 -62

-4 50 58

-5 169 164

-4 29> 17 -3 132 -1)4

-2 62 64

-1 1)2 135

0 29. -5

12. 12.1 -9 84 81

-8 42 -30

-7 17) -165

-4 49 31 -5 80 75

-4 77 -64 -3 74 -55

-2 96 92

1.13.1

5 52 -28

3.13.1

-7 44 -2

-4 144 12?

-5 74 -68

-4 97 -77 -3 99 -87

-2 114 97

-l 91 -75

0 60 -84

1 40 -1?

2 53 52

3 8) -66

4 70 -65

-7 59 -34

-6 5) 46 -5 26* -13

-4 42 -23

-3 *0 28 -2 170 156

-1 100 -89

0 121 -115

1 28* -19

2 132 126

7.13.L -7 62 46

-6 9) 90 -5 29* -22

-4 115 -106

-3 5) 44 -2 8) 71 -l 46 31

0 59 -5C

1 29* 22

9. 1 3.

-6 102 79 -5 57 33 -4 94 -47

-3 28» -l

-2 29» 21

0. 14,

3 3) -42

15,9.1

-15 121 104

-14 28« 24 -I) 121 -1)7 -12 49 -3)

-11 122 1)1 -10 40 -40 -9 75 -80

-12 61 86

-11 101 80

-16 104 -91

-9 26 * -22

-6 202 196

-7 18) 182

-4 96 -98

-5 60 -100

-4 179 176

-3 197 19)

2 169 -174 1 185 -192

0 8) 80

1 60 69

2 216 -211

3 67 -76

4 64 70

5 27» 25

6 215 -207

7 29. -3

25» -1 125 12)

1)3 123

74 -70

46 -47

9b 95 216 211

26* -19

99 -99

176 174

9) 91

0 179 176 79 -76 24* 19 149 149

228 214

142 -1)3

81 -76

111 100

82 79 28* -7

-7 80 -71

-6 144 -126

-5 39 4)

-4 42 -25

-3 6 ) -63

-2 146 -144

-I 152 147

0 23 * 3 ?

1 13) -105

2 54 -59

3 91 99

-2 28* 6 -1 127 116

15, 11 .L

-10 1)9 -129 -9 69 75 -8 43 49 -7 89 -6*

-6 75 -74 -5 134 141

4 31 15

6 . 12.1

79 41 171 149 27* -10

142 -1)9 27. -2)

169 159

49 -4)

-4 124 109 -5 73 -70

-4 204 -16)

-3 27« 24 -2 67 8?

-1 60 -38

0 102 -86

1 29* -24

2 64 64

3 51 -2)

4 77 -56

-1 114 -102

0 67 -57

1 127 102

2, 14,

-2 54 40

-1 29* -34

0 29* -14
- 8-

The large correlation coefficients are 0.25 between

the scale and the Ca J3j_ x anistropic temperature factor,

Q®75 between the Ca and g 1 a anisotropic temperature

factors, 0.68 between the Na x and z parameters and 0.78

between the Na ^3 and J3 X 3 thermal parameters. Most coefficients are, however, much less than 0 . 04 .

The atomic parameters are given in Table 3. The

hydrogen positions are those from the final least-squares

refinement and are recognized as being only approximate.

Discussion of the Structure of Gaylussite

The calcium environment .—The immediate Ca environment

is summarized in Table 4 and in Figure 1. Since the

strongest electrostatic attraction in the crystal is between

Ca2+ and C0§~, it is not surprising that both C03 “groups are

coordinated ( via 0(2) and 0(3) ) to Ca, which lies on a to be

twoTMfold axis, to form what may be considered/an ion triplet,

0C0s =-Ca-03 e0. The coordination of Ca is completed by four

water molecules, 0(5), 0(^), 0(6) and 0(6^). The Ca-to-0

distances are within the normal range. The strongest possible electrostatic repulsion in the structure, the Ca-Ca

interaction, is minimized by the Ca ions being widely

separated from one another (Ca-to«~Ca>4.5 A) .
Atomic

Parameters

of

Gaylussite -9-

TQ oo in ID in in 0)

x- wx "—xN

X c

C3 CD rH 1 1 O cD CN •H

(V i-H rH CDO o O CN

CQ 0 0 -p 3 i | i | rg 3 o tr> 0

X*-^ xx-^ 0)

p

rH ro in in CO

m

u

n v^x* >—

'*— " •*

— •>

—X V—' >«-x d)

CD 1 1 CN LO 00 O' CD oo CD r3 1 1 CD rH CO 1 1 00 rCQ 0 0 ^5 3

r-H rH 1 1 c rC

rd Eh

J T3 oo m "vl* Ct in in Q)

v_x- n-x* *»—* •'W'

v—^ 4-) CD CD i—

CD 1 1 o 00 0 O o OO O 1

1 1—1 ’Cf 3 o

0Q 0 0 O' 0 1 1 rH

COCD ii ,x-^ X—

X-—s

xX ^ X

X X^v x—

P

CN 00 cD cD in

m OO in

m 3 x—

N-x'

* 'w-' «* >—«* > * (T> 3

CD CD i" CO

m o Gc CN o o O o o o •H •rl

CD CO CD 1 1 CO a> Gc CN o m o o CN o o mh CLi CQ 0

rH 1 1 i—1 CN i—1 rH rH 1—1 rH rH rH •p

p 3 -p 3 0

CJ

w

•H •rH

xx—*x—

X s y—^

X s x s x—>X—^ CP '—

CM oo CD CD in in 00 CD CD •H >—

"—

x >—

' x C DQ

CD CN CO CO gc r- o o CN o o o o o iji

CD CN OO r-H CO o Gc CC o O o o CD o o •H +J

cq • 0 t 0 0 0 0 0 0 0 0 0 0 0 CO 3 r—1 i—1 i—1 CN CN 1 1 rH i—1 CN rH rH CN rH 1—1 -p -P

CO 3 3 3

x—

x—

x

V x—.X—*. X—-V x-»v

X s rH •P rH oo CD in CO in in 3

•X

**—

* ' -x 1* x 3

U) 3

CO CD CD st* 'cf o o o CN o o •H -p 0 0 LIO in OO <N o oc 00 o o o 1 1 o o p 3 3

CQ

m (D -P I—

rH i—

1—

f—

i—f—

1—

rH -H i—

P E , -P 3 0 Q) 00 Or E p G CN 3 •rH p

•H 0 X

x^ x-^x s X>

V X—

X— 3 O 0

rH CN CN rH 1—

CN CN CL) 3 p ' ’ * **—

x—

' X—>N .x—

x—X—

TG P II P Qj o r- * 1 oo Gc 00 o oo CO ro 00 Cc ro oo P 3 a

N o o CD oo 1 1 o >

1 CN

—

v

—1 O

— 3

CO 3 oj 2f 3

in rH 1 1 cD r~ 1 1 in rO

m 'sf rH o r- rrt t3 CL) rHO E0P<

rl O) (N

M C\| fO CN CN wcM^^HinHnin^noof'im

CN CN CO o 00 G^ oc ro 3^ ra ^ P 3 d 3

CTi CO CN 0^ o O o O'! i—

CO

O 3* GC 3

1-1 0 E P

rH rH o o o O CO CO CN CN ro 31 3’ 00

m

V

ip 3 rH 3 3 ^ P 3 P 1 1 ^ 'll P 3 E 3

+J * 0 Cl P E 3 p 3 fu X-^ x^-s. x—. x—

x-^. 3 2 p rH r3

p 1—

CN rH 1 1 1 1 rH 1—

P 6 3 3 P 3 1—

X—

X—«* xX-X X— (0 . V E d o rH oo CN oo CO o CN CD CN CN t" CN CN p p 3 o CO uo in 00 in o OC CD cp 3 3 rH o 00 00 CO o CD o in CD O rH 3* O CO d ^

•H ^

•H r3 CO 3 o o i—

CN 1—

i—

o o O rH i—

rH CN 1—

E P 0 3 W ® 3 P 0 P T3 •H 3 ^ 3 0 P * P •p Co r3 •H * 3 3 3 3 3

X—

x s X s x—* x—s .X—H X—X

K .X—S, X—N,

x—

Co 5 P P rH 0 1 1 CN 00 rH in CN oo CD 3- in •H H 3 •H rH d 3 3 "—

E > 3 C U u O O O o E o E E O E E * < E * O

>1 CL) 0 u3 P

to CO 3 p

rH 3

-p

COp

0) p

0)

are

only
-10 -

TABLE 4

The Calcium Environment in Gaylussite

atoms distance.

Ca # 0 (2) 2.573 (2)

Ca,Q (3) 2.385(1)

Ca,0(5) 2.484(2)

Ca,0 (6) 2.420(2)

Ca # 0 (4) 3.783(2)

Ca # 0 (4) 3.997(2)

*In all distance and angles quoted in this paper the values

computed

in parentheses are the/standard errors in the last significant

figures
- 11 -

The carbonate group . —The C03 group is essentially planar

with an average C-to-0 distance of 1.288^. Its dimensions

and environment are summarized in Table 5 and Figure 2.

Oxygen 0(1) is bonded electrostatically to Na (2.314^) and

is hydrogen bonded to water oxygens 0(5) (2.847A) via H(3)

(~2.0A) and 0(6) (2.667A) via H(5) (~2.0$). Oxygen 0(2)

is bonded electrostatically to Ca (2.573A), Na (2.400A), and

Na (2.610A) and is hydrogen bonded to 0(5) (2.852A) via H(2)

O (~2 # 1A). Oxygen 0(3) is electrostatically bonded to Ca

(2.385A) and Na (2. 331 A) and is hydrogen bonded to 0(6) (2.666A)

O via H(4) (~1.8A). The observed C-to-0 bond distances correlate qualitatively with the oxygen environments. Oxygens 0(2)

and 0(3), which are under strong anisotropic cationic attraction, have longer bond distances to the carbon than does 0(1).

Similarly, the 0(2)-C-0(3) bond angle, 118.1°, is less than

120° because coordination with the Ca pulls these oxygens

together

The two C03 groips coordinated to Ca are also coordinated to two Na ions (Figure 1) which cause a dihedral angle

of 134.3° between the planes of the two C03 groups instead

of the expected 180°. This coordination is instrumental in

making the 0(2)-to-0(3) vector in one C03 group very nearly

parallel to the 0 (2 '

-to-0 (3*) vector in the other C03 group.
- 12 -

TABLE 5

The Carbonate Anion and Environment in Gaylussite

O Atoms distance, A

C,0(1) 1.280(3)

C, 0 (2) 1.291(2)

C, 0 ( 3) 1.293 (3)

0(1) ,0(2) 2.247 (2)

0(1) ,0(3) 2.229(3)

0(2) ,0(3) 2.216(2)

Coordinated

atoms angle, deg

0(1) ,C, 0(2) 121.8 (2)

0(1) ,C,0(3) 120.1(2)

0(2) ,C,0(3) 118.1(2)

0(1) Environment

Atoms

O distance, A

0(1) ,0(5) 2.847 (2)

0(1) , H ( 3) 2.05 (2)

0 (1) ,Na 2.341(2)

0(1) ,0(6) 2.667 (3)

0(1) , H (5) 2.02(4)

0(2) Environment

Atoms 0 O distance, A

0(2) , Ca 2.573 (2)

0 (2) ,Na 2.400 (2)

0(2) , Na 1 2.610 (2)

0(2) ,0(5) 2.852 (2)

0(2) ,0(6) 3.364 (2)

0(2) ,0(4) 3.285 (2)

0(2) , H ( 2) 2.11(3)
-13-

TABLE 5

(continued)

0(3) Environment

Atoms

0(3) , Ca

0(3) ,0(5)

0(3) ,0(4)

0 (3) ,Na

0(3) ,0(6)

0(3) , H (4)

distanceA

2.385 (1)

3.096(3)

3.204(2)

2.331(2)

2 . 666 ( 2 ) 1.83 (2)
-14-

The Ca ion is 0.69A below the intersection of the planes of

these C03 groups.

The Na environment .--The sodium ion is coordinated

(Table 6 and Figure 3) approximately octahedrally by 0(1),

0 ( 2 ), 0(2'), 0(3), all in different C03 groups, and by the

0(4) and 0(5) waters. The repulsion arising from the Ca-toO Na closest approach of 3.626A is reduced by their sharing 0(2)

and 0(3') (Figure 1). These atoms are in the two C03 groups

bonded to the Ca. The next closest Ca-to-Na approach,

3.83lA, is stabilized by the intervening pair 0(2) and 0(5').

The Na-to-Na approaches are 3.903^. and 4.305A, and the small

stabilization required is provided by the intervening octahedral edges 0(2)-0(5) and 0(2) -0(2').

The water environments .—The water environments are

summarized in Table 7 and Figure 4. The 0(6) water is bonded

to 0(1) of one C03 group via a hydrogen bond H(5) to 0(1),

where H(5) to 0(1) ~2.0A, 0(6) to 0(1) = 2.667A, and to 0(3)

of the next C03 group (generated by the c glide) by a hydrogen

bond H (4) to 0(3), where H(4) to 0(3) ~1.8A, 0(6) to 0(3) =

O 2.666A. 0(6) is in the coordination octahedron of the Ca
-15-

TABLE 6

The Sodium Environment in Gaylussite

O Atoms distance, A

Na,0(2‘) 2.400 (2)

Na, 0(2) 2.610(2)

Na / 0(3') 2.331(2)

Na, 0 (4) 2.408(1)

Na, 0 (5) 2.475 (2)

Na ,0(1) 2.341 (2)
-16-

TABLE 7

The Water Environments in Gaylussite

H ( 1) ^(1)

1) the 0(4) water environment N 0 (4)

Atoms distance, &

0(4) ,H(1) 0.82(3)

0(4) ,0(6) 2.774(2)

0 (4) , Na 2.408(1)

H ( 1) ,0(6) 1.96(3)

H ( 1) , H ( 1) 1.14(4)

Coordinated

atoms angle, deg

H ( 1) ,0(4) , H ( 1 ’ ) 88. (3)

0(6) ,0(4) ,0(6') 79.37 (8)

0(4) , H (1) ,0(6) 174. (2)

H ( 3)

the 0(5) water environment \)(5

Atoms distance, A

0(5) , H (2

0.81(3)

0(5) , H (3) 0.81(2)

0(5) , Ca 2.484(2)

0(5) ,0(1) 2.847(2)

0(5) ,0(2) 2.852 (2)

0(5) ,Na 2.475 (2)

H (2) , H ( 3) 1.35(4)

H (2) ,0(2) 2.11(3)

H ( 3) ,0(1) 2.05 (2)

Coordinated

atoms angle, deg

H (2) ,0(5) , H ( 3) 113. (2)

0(1) ,0(5) ,0(2) 122.36(6)

0(5) ,H(2) ,0(2) 152. (4)

0(5) , H ( 3) ,0(1) 172. (4)
-17-

TABLE 7

( continued)

H (4) H ( 5

3) the 0(6) water environment x0(6)

Atoms

O distance, A

0(6) ,H(4) 0.84(2)

0(6) # H(5) 0.67 (4)

0(6) ,Ca 2.420 (2)

0(6) ,0(4) 2.774(2)

0(6) ,H(1) 1.96(3)

0(6) ,0(3) 2.666 (2)

0(6) ,0(1) 2.667 (3)

H (4) , H (5) 1.28(4)

H ( 4) ,0(3) 1.83(2)

H ( 5 ) ,0(1) 2.02 (4)

Coordinated

atoms angle, deg

H (4) ,0(6) , H ( 5

115. (3)

0(3) ,0(6) ,0(1) 106.87 (8)

0(6) , H (4) ,0(3) 171. (4)

0(6) , H ( 5) ,0(1) 162. (3)
-18-

ion and is the oxygen acceptor of a hydrogen bond from the

water molecule 0(4) on the two-fold axis. The distances in

these hydrogen bonds are H(l) -to-0 (6) ~2.0&, 0(4)- to -0 (6) =

O 2.774A. Besides linking two 0(6) waters to each other, the

0(4) water serves to separate two Na ions (Figures 1 and 4).

The 0(5) water connects 0(1) in one C0 3 group to 0(2) in the

C03 group related by a two-fold screw axis. The hydrogen

bonds thus used are 0 (5) —H( 3) . . . . .0 (1) , where H(3)-to0(1) -2.0A, 0(5)-to-0(l) = 2.847A, and 0 ( 5

) -H ( 2 ) 0(2),

where H(2)-to-0(2) -2.1A and 0(5)-to-0(2) = 2.852A. Also 0(5)

is in an edge which is shared between neighboring Na coordination octahedra.

Determination of the Crystal Structure of Pirssonite

We determined the crystal structure of synthetic pirssonite,

CaNa2 (C03 ) 2 *2H2 0, before the recent work of Corazza and

Sabelli4 came to our attention. There are enough differences

in the two procedures to warrant a brief description of our

determination. They used a mineral specimen ground to a

sphere of 0.616 mm diameter, measured 481 reflections of

observable intensity from integrated films with a microdensitometer, corrected for absorption, and refined using

block-diagonal least squares.
-19-

In the present work, good crystals of synthetic pirssonite were grown at 50 °C from a solution of 27% by weight of

Na 3 C03 and 5% NaOH in water in contact with powdered calcite. 5

A small crystal, maximum dimension 0.20 mm (uMo = 10.6 cm

-1

)

was selected. The cell dimensions* were determined to be

a = 11.340 ± .004, b = 20.096 ± .005 and c = 6.034 ± .002 A from

20 values of axial reflections observed on a diffractometer.

Evans1 2 reported the dimensions a. = 11.32 ± .02, b = 20.06 ±

.02 and _c = 6.00 ± . 02A, and that the space group is Fdd2.

Our values, which were calculated using the weighted mean value

for Mq Kaj. , a 2 radiation (X = .71069 $ are systematically larger

than these reported by Evans.

Over 2200 reflections from two octants of the reciprocal

lattice were measured on a diffractometer 7 with the peak

height procedure used for gaylussite. These data were merged

into a unique set of 1141 reflections, 1079 of which were

of observable intensity. The R value between reflections

accepted as equivalent was 0.027 based on F's. The quasiunitary structure-factor statistics are given in Table 8

and confirm that the space group is acentric. Weights based

on the counting statistics were used in the full-matrix

least-squares refinements. The atomic scattering

*The uncertainties quoted on cell dimensions are estimates

based on experience with the technique iBed for measurement

and in the authors' opinion may be treated as standard errors.
- 20-

TABLE 8

Quasi-Unitary Structure -Factor Statistics for Pirssonite

^ |e | y ( \e 2 |> ^|e2 -i |>

all reflections .879 1.000 .731

3-dimens ional

reflections only

.875 .968 .694

Theoretical centric

Theoretical acentric

.798

.886

1.000

1.000

.968

.736

obs. centric acentric

Fraction of E's > 1.0 .394 .317 .368

« o

CN .014 .046 .018

3.0 .0002 .003 .0001

Number of reflections 1140

Suggested overall temperature factor 0.65
-21-

factors used for gaylussite were also used for pirssonite.

No corrections for absorption were made.

All atoms other than the water molecule were found from

the sharpened Patterson map. The oxygen of the water molecule

was found from an F 0 Fourier synthesis. The structure was

refined isotropically to R w = 0.059 and then anisotropically

to R w = 0.042. These hydrogens were found from a difference

synthesis and were included with fixed thermal parameters

(B h = 1.0A2 ). The structure was then refined anisotropically

to R w = 0.029, R a= 0.044. The largest correlation coefficients are about 0.2 and are between the scale factor and

some of the anisotropic temperature factors, between some of

the anisotropic factors themselves, and between the x and y

parameters of most atoms. Most of the remaining coefficients

are less than 0.05. The observed and calculated structure

factors are given in Table 9.
22

TABLE 9

Observed and Calculated Structure Factors for Pirssonite

Columns are l, 10F0 , 10F C and phase in millicylces

?? re 1*3

13 106 110

ft *00 )** 90*

7 *71 *6* 7*3

16 >23 >22 20 2*0 2*2

2* 122 126

3* 19* 10*

21 101 100 112 l) 2*3 2*1

6 101 109 *90

0 19* 13* 0*0

10 129 130 *61

12 3*0 333 *3*

13 1*7 1*3 709 l* 13 3 *22

17 207 212 200 16 1* 13 692

l* 19* 16* **0 20 132 133 *70

21 *7 ** *99 22 2* 22 97* 29 *3 *2 762 2* 103 103 *7*

20 >0 *37 16 2*

111 11? *9*

32 31 *11

*7 *2 29*

1 220 222 *22 2* 36

3 1*3 1*6 107 26 10*

*9 97 8*6 27 102 ** 637

63 6*2 17 1*3

137 136 131 16* 167 072

110 116 7*1

113 116 169

2 2*0 23* 731

6 170 1*7 963

1* 106 109 697

16 100 112

72 6* 36 29

10* 106 830 31 *9 73* 32 137 121 *60

96 *9 939

22 116 127 62* 17 59 26 132 1*1 6*

30 130 1*3 **3

19 111 10* 116

2 2*0 299

197 197 121 208 210 60 10 383 *00

12 1*0 136 263

16 222 230 2* 7* 66 *0

2 167 177 *91 30

6 1*1 1** *?* 32

10 293 306 *72 i*

12 218 220 300

1 160 130 1«*

J 323 326 *73

3

' 73 7* 7*1

7 2*9 2*3 3*3

02 67 63*

69 67 937

2 126 120 *79

* 22 23 392

*3 *7 9*3

2 371 369

12* 132 300

12 55 37 *07 16 199 199 0 1* 100 102 113 20 126 138 900

16 21 12 *62 22 *0 96 0

10 1*6 1*6 *60 2* lie 3 0 20 22 21 301 26 1*3 136

198 30 28 30

63 62 900 13 82 62 27'

21 123 120 917 26 67 63 *97 32

23 126 126 116 20 I

77 72 191

71 63 800

0 126 129 107

2 111 113 *33

* 127 120 *39

2 168 167 663 29 52

* *36 *38 *31

80 70 279

317 9*7 12 *0 101 *99

7 131 13* 736

22 123 l 22 2* 10* 106

30 128 11*

7 *0* 16 66 *7 220

0 677 *89

2 *96 300 *2* 100 102 069

177 166 812 17 135 133 2*3

10 196 206 967 23 12* 12* 6*1

12 126 12? *10 23 *6 *6 268

11 136 1)7 *06 20 6) 60 *3 20 102 10* W 1*8 131 83 22 !*• 2 829 22 36 *3 2* 106 110

*7 *6? 30 *0 36 2*0 21 97

22 13 *?* l* 17* 16* *0 27

10 107 113

20 *7 *3 *31

16 207 206

39 *7 *0*

97 100 *76 31 61 20 1** l** *77

2* 100 102

6 120 II*

37 *98 32 66 61 995 130 136 126

110 107 1*6 2*7 2*6 *1?

289 283 325

1*0 1*8 *7*

*2 ** 22*

10* 108 762

3 2*3 293 955

3 152 153 638

* 222 227 052

11 139 163 9*1

179 15 21 22 *6*

161 15* *31

55 33 128

17 2)3 238 22 13* 132

* 2?) 26* 20 10 187 192 *72

71 70 1*3 23 32

11 171 17*

1) 5* 60 03*

13 299 301 10*

1* 1*9 151

31 30* 27 62 92 *2

23 123 119 896 32 39 31 68*

41 192 1)9 829

2) 13* 1)7 1*3

23 31 3* 689

*0 97 32*

97 103 975

*1 20 3* *0 320

22 1*2 138

33 11* 100 692

1 *3 100 239 33 33 28 125

72 70 *9)

27 53 36 268 20 30

61 62 989

90 123 32

30 129 11?

39 *2 81 13*

65 66 905

53 35 10 69 66 600

71 73 275

71 70 979

70 76 96*

38 36 780

w 260 290 9*3

2 209 218 ***

* 110 119 223

6 87 90 98*

0 21* 223 9*7

10 6* 60 **S

12 91 09 127

11 102 109 839 1* 116 121 893

1 01 09 165

9 206 281 9*6

3 96* 3*9 *2

7 220 227 7*5

3 263 266 837

9 29 28 162

9 160 173 202

11 210 207 936

19 111 117

17 113 117

56 36 285

10 36 63 *62

16 31 *7 52*

«* 2* 107 132

20 70 *0 996

30 39 )» 037

21 70 70 662 23 33 29 166 23 107 101 06) 27 93 90 1)0

120 120 *7*

2* 30 * 53 65 162 7* 75 768

80 6* 6) 11 106 116 95?

9? 98 9*6

23 25 3*3

1* 62 65 27

l?0 1?* *9*

19* 191 970

*1 *3 300

117 120 939

1)3 1)3 962

9) *6 9*3 22 1)7 1)3

900 19 93 90 500 21 8? 66

6 2*9 307

6 327 333

23 10) 102 767

23 16 135 139 966 10 25* 291 900 29 61 63 61

15 272 262 87*

21 190 197 60 2* 61 61 23 138 107 803

25 7* 7* 1 22 28 89

27 3) *7 9*7

29 00 02 *9

!*• 20 710

10* 100 010

1 3 3 92 67*

9 3* 98 99*

9 239 2*0 8*6

2 118 123 *97

*2 98 88*

18 *6 *7 500

20 3* 23 500

22 2* 2* 900

2* 100 10? 0 2* 11* 1 o 28 1)9 1** 0 )0 ** 36 300

33 101 65 173

3 207 216 107

*6 105 29 20

10 1*6 1*9

72 7* >99

112 118 165 1* 3* 98 9* *62 16 *3

11 83 *1 231 16 11* 122 3 13 ISO 1*2 92* 20 2* 21 809

13 1** 1*8 90 22 9* *8 99*

17 106 112 979 2* 2* 19 *02

1* >9 32 33

11 1*1 1*5 9 3* 39 2? 0 IS 109 11* 97*

19 *6 *8 29) *.R»2 17 12* 119 831

l* 10* 107 *2

2 3)3 9*0 96 21 107 109 13

* 2* 26 39* 23 *8 95 1*3

* 226 23* 9*6 23 *1 36 766

21 123 122 886

23 80 7* 192 29 76 01 778

27 32 2? 76

29 01 76 902

31 10* 9* 189

l 191 139 170

3 ? 2 70 966

9 90 10? 13)

T 03 67 096

1 00 92 86

11 60 *9 939

12 *0 92 *90

l* 179 183 961

16 90 63 57

* 160 13?

1 260 2*3

17 107 103 V76

19 102 101 812

21 *6 *6 169 9* 9* 9)7

3# 53 921

* 126 131 2?0 27) 927 99 63 99*

1) 1)0 1*0 923 12 76

32 30 1*1

17 120 127 902

19 101 100 156

90 89 99Q

91 716 20 8*3 23 67 79 953 2* ?

11 115 112 107

13 *9 90 11) 29 9 9 13 27 29 181 31 73

10) 102 066

1)1 132 119

100 106 6**

>6 32 *09

i 06 10) *66

19* 197 225

1*3 131 700

1)9 1*1 96)

*7 52 129

11 107 106 036

1)3 1)7 6*0

107 109 8*6

110 10* 16?

61 3* 1666) 11 120 120

151 1*7 30 29

6 2*1 2*6 993

8 )6 36 62?

10 110 110 69*

12 27 26 366

1* 196 196 931

16 30 23 926 1J 76 7? )**

10 33 96 216 19 62 60 919

20 5* 5* 9*0 17 0? 90 27 22 113 129 67* 19 61 60 87) 2* ll» 7 *3* 21 75 72 l?8 50 9*0 28 36 *6 371

62 62 9)8

18 111 107 999 32 29

30 106 101 9)3

22 *2 *3 979

63 6) 225

1)9 1)9 *10

120 12* 99)

6 37 59 *49

0 112 113 393

3* 39 |?9

*2 38 819

90 II 199

1* 12* 1)3

16 110 11* 993 20

19 19 22 2*2 22

69 20 129 12*

0 108 122

10 2*3 2*3

20 Ct 19 22 1*0 159 358 2* 17 2*

99 103 30 22 2* 20 1** 26

10 162 30

* 4? 30 9*1 26 97 83 33

6 29 28 9** 29 2* 22 39

0 92 102 20 30 31 *7 686

10 S* 35 *9? 32 23 19 *16

12 90 99 961 3* 109 91 30

I* 69 69 975

9.1,7 3 128 131 *68 2* 9)

? 111 117 95 2* 13*

l 92 93 3 9 327 3)6 190 28 5*

3 110 113 92V 11 212 222 926 30 16*

5 ** *? 215 1) 75 72 582

7 122 127 777 13 60 56 67 0,1 9 11* 11* 1*2

11 107 10? 922

17 159 15* 171 19 129 131 0)3

19 30 31 01* 2) 21 17 96*

17 127 122 139 29 109 101 160 19 109 10? 821 27 95 10 196 159 991

* 2)8 2*7 965

* 19* 19* 492

0 1*5 152 111

10 107 110 91* 119 120 900

io) toe 86? 876 26* 226

13 589 29 *5 *5 2*7 *5 052 >1 *3 *2 086 l* 13* 1*0 990

*71 29 80 70 128 >3 ?7 61 122 62 37 900

69 *6 99)

67 7* 26

101 100 916

1*9 1*9 V60

1*6 1*6 97)

33 32 090

22 30 22 «*)

25 32 639

71 71 965

0 132 13*

•6 92 668

39 *9 13*

7) 76 827

1 1*2 1)6 107 21 97 97 76)

3 11* 12 692 2) 92 §6 90

75 79 910

39 52 2*7

3 1*0 1*2 771

» 91 9* 30

7 10) 105 9*9

9 9* *3 177

11 70 71 781

1) 1)2 129 120

19 2) 20 9*1

21 99 69 122

2) 11* 10) 622

*2 5* *22

13* 13* 19)

92 9 ) fso

112 10* 713

*0 9) 227

30 9* 91*

117 111 20 17 69 07 6*3

99 *2 290

*5 *7 796 79 76 91 79 02 09)

6* 63 900

13 *2 »* 120 *3 *2 079

70 01 173 90 *3 6)6

7 121 12) 66*

9 68 71 192

11 2) 2* 76?

2 192 19?

62 9*) 80 128 It* 900 1* 90 99
23

TABLE 9

( continued)

16,*,0

16 16 11 500

16 156 161 0 20 !)• 2 500

22 61 76 0 26 IS# 16 500

26 60 T6 0

16 ,K , 2

0 12 T 1)6 99)

2 60 65 TT7

6 52 56 725

6 )1 35 16)

6 157 15) 9 10 17 11 69)

12 76 82 666

16 33 32 592

16 66 8) 3 7 16 2» 22 316

20 60 60 906

22 16* 16 911

26 56 56 5

16,*,

2 113 11) 65

6 26 27 )72

6 101 10) 56

6 30 18 525

10 66 6) 65

12 52 50 697

16 86 60 51

16 6) 39 69)

18 96 61 15 20 61 56 976

22 92 86 27

16, K,

0 156 157 955

2 35 36 177

6 62 36 69

6 65 60 816

6 17) 166 950

10 26 25 667

12 86 77 30 16 27 17 1)7

16 96 96 938

13,*.

1 63 66 220

3 90 88 626

5 77 71 106

912

878

715 99) 866

152 962

910

I 13* 16 163

J. 61 56 783

5 97 67 53

7 66 65 866

9 66 37 362

11 60 36 93)

1) 89 81 126

15 70 70 778

17 16* 16 21

15,

K,

1 56 53 890

3 70 69 207

5 63 56 976

7 63 37 86

16.

K.0

0 219 226 0

2 70 71 500

6 20 0 0

6 96 96 0

6 126 128 0

10 33 30 500

12 55 66 0 16 13* 16 0

16 91 83 0

16 16* 3 0 20 100 96 0

16, K,

2 86 69 981

6 23 19 670

6 76 75 35

6 32 30 572

10 1)9 139 972

12 26 16 881

16 3) 35 937

1 6 12* 11 696

18 109 98 39

20 36 30 75,7

16, K,

0 63 59 0 2 13* 6 206

6 96 100 986

6 32 29 0

B 52 30 26

10 31 23 391 12 61 62 37

16 16» 10 180 16 66 77 979

16 32 26 3*0

16,*,

57

6198

17,*,

56 6 82 6 96 9 26 26)6

631

112 876

69

756

16)

680

70

1 13* 3 738

3 66 79 952

3 117 116 106

7 26 20 659

9 67 65 610

11 77 7) 966

13 77 76 66

15 39 31 665

17 5) 66 302

17,*,

1 62 39 962

3 77 72 100

3 1)0 116 671

7 3* 6) 223

9 29 26 736

11 86 66 95

18 ,* ,0

2 39 62 0

6 30 29 500

6 60 60 0

6 39 36 0

10 101 9) 0 12 72 7) 500

16 13* 10 0 16 25 16 0

16,*,

2 33 36 667

6 106 109 970

6 23 26 106

8 79 79 93

10 2) 2) 679

12 79 62 6 16 67 62 113

16 76 71 36

16, K.

2 61 76 966

6 13* 20 692

6 63 36 933

6 16# 9 360

10 121 111 936

16,6,

1 51 37 157

3 75 71 696

3 71 71 93

7 30 36 766

9 66 62 60

11 72 68 901

1) 30 36 62

19,

*,)

1 39 36 1

3 61 71 961

3 63 33 7)6

7 6) 33 306

9 3) 67 976

20,

R,0

0 30 66 0

2 33 21 500

6 66 86 0

6 13# 0 0

6 8) 60 0

20 . 1,2

2 67 62 12

6 13# II 711

0 117 119 90
-24-

The atomic parameters obtained by us, as well as those

of Corazza and Sabelli, 4 are given in Table 10. The agreement between the two sets of parameters is excellent. All

positional parameters for atoms other than hydrogens are

within 2 a when our estimated standard errors' are used;

four of the 18 parameters differ by more than 2a when the

estimates of Corazza and Sabelli 4 are used. Their estimates

of errors, which are about 60% as large as ours, were derived

from the block-diagonal least-squares approximation using

only 481 observed reflections and are probably too small.

The placement of the hydrogen atoms from our refinements

is recognized as being only approximate. Corazza and Sabelli

apparently assumed that the 0 (4) -H ( 1) . . . . . 0 ( 1) and 0(4)-H(2)

.....0(1') hydrogen bonds are linear in placing the hydrogen

atoms. This is reasonable since the 0 (1) -0 (4) -0 (1 ' ) angle

is 108.7 ± .4°.
- 25 - oH

03<

Eh

CD -P •Hco

COpP

•H

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4-1o

COP

CD -P

(D6

rdp

rd 03oH

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CD CM co co CO ro

cv

V *—

CQ i o o CM

O CM i 1 o o O O O o * 0 1 *

CSO CD CD CO Oo

cvH CO CO CM CM CM

c-

—

CQ i O rH co co o ro i 1 1 1 sf sf CM co cD r 1 ‘

CV rH CM CM CM CM CM CM v—

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03 o O

O 1 1 1 1 CD i 1 o O o o O o O 1 1

co CD o 1—t CO CD

co CD 1 1 co co CM ro co

cq

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->

1 O CM 40 co 40 (M 40 CO 40 CM o CD o o 1 1 pH 1 1 rH rH

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cv CO CM co CM CM CM ro

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co Do 40 rH 40 Oo

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CD 00 o 00 CM 00 o o

CM 1—

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CM s 'sf CO 00 o 40 o 40 00 o

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N o o r- r- Do CM i—

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CM 'cd

— o o o o o O O 1 1 rH CM CM 'Ct CD CD co o CM o o 01 o o O1 01 O 1 1 1 1 rHi 1 1 1 O O o o CM CM

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S ' " ^ ^ 

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X o o co co 1—1 go

H CM CM r- i—1 co CO rH 1 1 o o in 40 co CD 40 40 0

oo Oo CO d- 1 1 o o CD CD 00 CO i—

rH o O CM CM

O o CD CM CM rH o o 40 40 o o 1—1 i—1 o O 1 1 1 1 CD CD 40 40 CD CD

X

c/a co 1 1 CM ^d CM 1 1 4- rd rd • ' ^ • E 6 u S3 CD O o O o X K O X

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X < •X

•X

X N. ^ N

X X—

03 1—1 CM co rH CM

4- (X5 rd 'W' p u X u o O o O ffi X

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CDD>op

>i

.G

CD x:

Eh•

CV • CM < CM o • • rH II

II CD i—

, . CD u >i •H CD X0 P p CO -p rd 0 H

CO •H P — 0

ip P P

-P 0

rd

pp

-P CD C \rd -P -P cp

co •H C rQ 0 CO o

CD -p Do •H Dh rd

•rH

H <u P i—

i—

rV! CD i—

<U >

0) rQ <D <

rQ rd

p

rd co <u co • 'O CD TS a CO -P C rd p rd

rd CD E

rd •P •H

rd

N CD

X

N

N E 0 N rd rd p

rd P P X u 0 rd X 0 U O, rd u

>i

H 3P

CO rQ rd 1—

+ E C u c P 0

Cl) CD I. > rQ CD •H -p P p Do rd o Q

CQ CD co

Cr>p

m cp 0 CD •H 0 P -P & T) CD -p n Sp E

a) XI rd - 3 p

CQ i—

1—

id + rd 1—

X P > <

•X -X •X * **
- 26-

Discussion of the Structure of Pirssonite

The calcium environment.—As in gaylussite and CaC03

•

6H2 0, 13 the Ca ions lie on two-fold axes. Their immediate

environment in pirssonite is summarized in Table 11 and

Figure 5. In these tables we have numbered the atoms in the

C03 group to correspond to gaylussite. The correspondence

between our numbering scheme and that of Corazza and Sabelli

is shown in Table 10. The strong electrostatic attraction

between Ca2

and CO|“ forces the formation of 0C02 -Ca-02 C0

ion triplets as in gaylussite, but, since there are only two

water molecules present, further coordination of C0| _ groups

to neighboring triplets is necessary to complete the Ca

environment. This is a step towards the coordination in

calcite and aragonite where each oxygen in a C03 group is

and three respectively

coordinated to two/different Ca ions/and the coordination

of Ca is octahedral. In calcite and aragonite, no C03 group

has two oxygens bonded to the same Ca. In gaylussite and

pirssonite, however, the Ca coordination comprises two C03 edges and four other oxygens. In pirssonite only two of the

latter are water molecules; the other two are C03 apexes

(Figure 5) . The two C03 groups coordinated to Ca by their
-27-

TABLE 11

Ca Environment in Pirssonite

O Atoms distance, A

03,0(1) 2.428(9)

Ca,0 (2) 2.461(7)

Ca, 0 (3) 2.536(7)

Ca, 0 (4) 2.483(10)
28-

edges are at a dihedral angle of 95.5° to one another, and have

twisted around to allow the close approach to Ca of the apexes

of the other C03 groups,, The Ca lies O.XA away from the intersection of the planes of the C03 groups coordinated edgewise.

The carbonate group .—The C03 group is planar and trigonal within experimental error with an average c-to-0

O distance of 1.286A. Its dimensions and environment are summarized in Figure 6 and Table 12. Oxygen 0(1) is bonded

electrostatically to Ca (2.428A) and forms two hydrogen bonds,

0(1) —to—H (1) -2.2A, 0(1) -to-0 (4) = 2.716A, and 0(l)-to-H(2)

o c ~1„8A, 0(1) -to -0(4) = 2.865A, with neighboring water molecules.

O Oxygen 0(1) is too far from Na (2.945A) for Na to be its

primary coordination. Oxygen 0(2) may form a very weak hydroO gen bond with H(X) (2.4A) but its primary coordination is

o electrostatically to Ca (2.461A) and to the 'chain' of Na

ions (2.299A, 2.302A) formed above it by the d glide (Figure

7). Oxygen 0(3) is not hydrogen bonded but is electrostatically

bonded to Ca (2.536A) and to a 'chain' of Na ions (2.351,

2.392A) formed below it by the d glide. The C-to-0 (2) and

C-to-0 (3) distances are shorter (1.28A) and C-to-0 (1)
-29-

TABLE 12

Carbonate Group Dimensions

Atoms

C—0 (1)

C-0 (2)

C-0 (3)

Coordinated

atoms

0(1) ,0(2)

0(1) ,0(3)

0(2) ,0(3)

0(1) Environment

Atoms

0 (1) , Ca

0(1) ,0(4)

0(1) , H ( 2)

0(1) ,0(4')

0(1) , H ( 1)

0 (1) ,Na

0(2) Environment

Atoms

0(2) , Ca

0(2) ,H ( 1)

0(2) ,0(4)

0(2) ,Na

0(2) ,Na'

and Environment in Pirssonite

O distance, A

1.300(12)

1.276 (14)

1.281(14)

angle, deg

120.5(1.1)

120 . 1 ( 1 . 1 ) 119. 4( .9)

O distance, A

2.428(9)

2.716(15)

1.8(2)

2.865(11)

2.2(1)

2.945 (10)

distance, A

2.461(7)

2.4(1)

3.118(11)

2.299(12)

2.302(9)
-30-

TABLE 12

(continued)

0(3) Environment

Atoms

O distance, A

0 (3) , Ca

0(3) ,Na

0(3) , Na 1 0(3) ,0(1')*

0(3) # 0 (1") **

2.536(7)

2.351(12)

2.392(9)

3.023(10)

3.177 (10)

*both coordinated to same Ca

**separated by d glide
-31-

o (1.30A), the reverse of that in gaylussite, and the 0(2)—

C-0(3) angle is essentially 120°. Presumably this, if a

real difference, is due to the moderating influence of the

coordinated 'chain' of Na ions, producing forces at right

angles to those produced by the Ca ion, and to the fact that

0 (1) is coordinated to a Ca ion at a Ca-to-0 distance

slightly less than those of 0(2) and 0(3).

The Na environment . —The Na ion is coordinated approximately octahedrally . Its coordination is summarized in

Table 13 and Figure 7. The repulsion associated with the

0 Na-Na" and Na-Na' closest approaches of 3.255A is reduced by

the intervening 'octahedral' edges 0(2') -0(4) and 0(2) -0(3'),

which are the most closely coordinated oxygens of the Na

octahedron. Na, Na ' and Na" are all related by the d glide.

The water molecules, which complete the coordination of Na,

are primarily coordinated to Ca.

The low charges of the Na and the atoms in the water

molecule, together with the A dependence of electrostatic

energy, allow the water molecule to coordinate to Na with

a the large Na-to-0 distance of 2.722A, where, other things

0 being equal, 2.3A is expected.
-32-

TABLE 13

The Na Environment in Pirssonite

Atoms distance.

Na, 0 (3) 2.351(12)

Na, 0 (2) 2.299(12)

Na, 0 (2 '

2.302 (9)

Na , 0 ( 3

'

2.392(9)

Na, 0 (4) 2.722(10)

Na, 0(4') 2.751(10)

Na,Na 1 3.255 (8)

Na,Na" 3.255 (8)
-33-

The water environment .—The geometry of the unique

water molecule and its environment are summarized in Table

14. Through its two hydrogens , the water molecule links

two C03 groups together (Figure 6) and is also coordinated

C electrostatically (2.483A) to Ca. The water molecule is

. ° o also coordinated to two Na 10ns (2.722A, 2.751A), and reduces

their mutual repulsion. It appears in the coordination of

Na twice (Figure 7) . In forming hydrogen bonds in the

pirssonite structure, the hydrogens of the water define a

plane which is approximately perpendicular to the configuration Na-0(4)-Na (angle = 164°) , using the two Na 1 s mentioned

above.

Acknowledgement . —Collection of the diffractometer data

was made possible with the advice and help of F. A. Mauer

and the cooperation of E. C. Prince in using the SDS 921

computer. We acknowledge the extensive cooperation of J. M.

Stewart in using the x-ray 63 system of crystallographic

computing programs
“34TM

TABLE 14

The Water Environment in Pirssonite

Hn H2 \/o'

Atoms

O distance, A

0(4) ,H(1)

0(4) ,H(2)

H (1) , H( 2)

.8(1)

1.0(2)

1.5(2)

0(4) ,0(1)

0(4) ,0(1‘)

0(4) , Ca

2.716 (15)

2.865 (11)

2.483 (10)

0 (4) ,Na

0(4) ,Na

2.722(10)

2.751(10)

Coordinated

atoms angle, deg

H ( 1) ,0(4) ,H (2)

0(1) ,0(4) ,0(1)

0(4) , H ( 1) ,0(1')

0(4) ,H(2) ,0(1)

118. (15)

108.7(4)

147. (13)

153. (11)
- 55-

References

1. W. E. Brown and B. Dickens, submitted to Science.

2. C. Palache, H. Berman and C. Frondel, Dana's System

of Mineralogy, 7th ed., Vol. II, p. 234, (1951).

3. Reference 2, p. 232

4. E. Corazza and C. Sabelli, Acta Cryst., 2_3, 763 (1967).

5. C. R. Bury and R. Redd, J. Chem. Soc., 1160 (1933).

6. R. Brooks, L. M. Clark and E. F. Thurston, Phil. Trans. Roy.

Soc., A243 , 145 (1951).

7. F. A. Mauer and A. L. Koenig, paper #10, Summer meeting

of American Crystallographic Association, August 1967,

University of Minnesota, Minneapolis, Minnesota.

8. International Tables for Crystallography, The Kynoch

Press (1962)

9. See C. Dickinson, J. M. Stewart and J. R. Holden,

Acta, Cryst., 21 , 663 (1966) for the method used in

estimating the quasi-normalized structure factors.
-36-

10. Reference 8, Vol. Ill, p. 202.

11. R. McWeeney, Acta Cryst., 513 (1951).

12. H. T. Evans, Amer. Min., 35 , 26l (19^8).

15. B. Dickens and W. B. Brown, In prsparatlon.
^ • Th© calcium ion environment

in gaylussite. Primed atoms are related to unprimed atoms by the two- fold axis.
Pig. 2. The carbonate anion environ

ment in gayluasite.
O Ca

a

Pig. 3. The sodium ion environment in

gaylussite.
© Ca

© Na

Pig. 4. The water en¥ironments and

hydrogen bonding in gaylussite.
Pig. 5. The calcium ion environment

in pirssonite.
Pig. 6. The environments of the CO,

anion and water molecule in pirssonlte.
2

1

pirssonit

TM8 SOdlU” l0n envlronment in


I