# Borate chloride

The borate chlorides are chemical compounds that contain both borate ions and chloride ions. They are mixed anion compounds. Many of them are minerals. Those minerals that crystallise with water (hydrates) may be found in evaporite deposits formed when mineral water has dried out.

## List

| | Chemical formula | Molar mass (g/mol) | Crystal system | Space group | Unit cell (Å) | Volume (Å$^3$) | Density (g/cm$^3$) | Comment |
| Teepleite | Na$_2$[B(OH)$_4$]Cl | | tetragonal | P4/nmm | a = 7.25, c = 4.84 | 254.4 | 2.076 | Colourless, white or light beige crystals, with a vitreous, greasy, or dull lustre. Uniaxial (-) n$_ω$ = 1.519 n$_ε$ = 1.503 Max birefringence δ = 0.016 |
| Boracite | Mg$_3$(B$_7$O$_{13}$)Cl | | orthorhombic | Pca2$_1$ | a = 8.577, b = 8.553, c = 12.09 Z=4 | 992.5 | 2.95 | Green, dark green (ferroan), blue, colourless, grey or white crystals with an adamantine, vitreous lustre if transparent. Biaxial (+) n$_α$ = 1.658 - 1.662 n$_β$ = 1.662 - 1.667 n$_γ$ = 1.668 - 1.673 2V 82° Max birefringence δ = 0.010 - 0.011 |
| Karlite | Mg$_7$(BO$_3$)$_3$(OH,Cl)$_5$ | | orthorhombic | | a = 17.92, b = 17.6, c = 3.1 | 978 | 2.80 | White to light green crystals with a silky lustre. Biaxial (-) n$_α$ = 1.589 n$_β$ = 1.632 n$_γ$ = 1.634 2V 24° Max birefringence δ = 0.045 |
| Shabynite | Mg$_5$(BO$_3$)(OH)$_5$(Cl,OH)$_2$·4H$_2$O | | monoclinic | | | | 2.32 | Colourless or white crystals with a silky lustre. Biaxial (-) n$_α$ = 1.543 n$_β$ = 1.571 n$_γ$ = 1.577 2V 49° Max birefringence δ = 0.034 |
| Satimolite | KNa$_2$Mg$_2$Al$_5$[B$_{12}$O$_{18}$(OH)$_{12}$](OH)$_6$Cl$_4$·4H$_2$O | | trigonal | R3m | a = 15.1431, c = 14.456 Z=3 | | 2.1 | White to colorless crystals with a vitreous or dull lustre. Biaxial (-) n$_α$ = 1.535 n$_β$ = 1.552 n$_γ$ = 1.553 2V 26° Max birefringence δ = 0.018 |
| Kalborsite | K$_6$Al$_4$BSi$_6$O$_{20}$(OH)$_4$Cl | | Tetragonal | | a = 9.85, c = 13.06 | 1,267 | 2.5 | Colorless with a slight rose-brownish tint crystals with a vitreous or pearly lustre. Uniaxial (+) n$_ω$ = 1.525 n$_ε$ = 1.525 ? Max birefringence δ = 0.000 |
| Hilgardite | Ca$_2$B$_5$O$_9$Cl·H$_2$O | | triclinic | P1 | a=6.463 b=6.564 c=6.302 α = 61°38', β = 118°46', γ = 105°47' Z=1 | 205.8 | 2.67 to 2.71 | Colorless, light pink crystals with a vitreous lustre. |
| Solongoite | Ca$_2$(H$_3$B$_3$O$_7$)(OH)Cl | | monoclinic | | a = 7.93, b = 7.26, c = 12.54 β = 94° | 720 | 2.514 | Colourless crystals with a vitreous lustre. Biaxial (+) n$_α$ = 1.510 n$_β$ = 1.510 n$_γ$ = 1.545 Max birefringence δ = 0.035 |
| Ekaterinite | Ca$_2$(B$_4$O$_7$)(Cl,OH)$_2$·2H$_2$O | | hexagonal | | a = 11.86, c = 23.88 | 2,909 | 2.440 | White or white with slight rose tint crystals with a pearly lustre. Uniaxial (-) n$_ω$ = 1.577 n$_ε$ = 1.574 Max birefringence δ = 0.003 |
| Chelkarite | CaMgB$_2$O$_4$(Cl,OH)$_2$·5H$_2$O or near Cl:OH = 3:1 | | orthorhombic | | a = 13.69, b = 20.84, c = 8.26 | 2,357 | 2.21 | Colorless crystals. Biaxial (+) n$_α$ = 1.520 n$_γ$ = 1.558 Max birefringence δ = 0.038 |
| Sakhaite | Ca$_{48}$Mg$_{16}$(BO$_3$)$_{32}$(CO$_3$)$_{16}$·2(H$_2$O,HCl) | | isometric | Fd3m | a = 14.685 Z=4 | 3166.8 | 2.78 - 2.83 | Colourless, gray to grayish white crystals with a greasy lustre. |
| Hydrochlorborite | Ca$_4$B$_8$O$_{15}$Cl$_2$·21H$_2$O | | monoclinic | | a = 22.78, b = 8.74, c = 17.06 β = 96.7° | 3373 | 1.83 - 1.85 | Colorless crystals with a vitreous, dull lustre. Biaxial (+) n$_α$ = 1.499 n$_β$ = 1.502 n$_γ$ = 1.521 2V 45° Max birefringence δ = 0.022 |
| Heidornite | Na$_2$Ca$_3$B$_5$O$_8$(OH)$_2$(SO$_4$)$_2$Cl | | monoclinic | C2/c | a = 10.19, b = 7.76, c = 18.81 β = 93.33° Z=4 | 1,485 | 2.753 | Colorless crystals with a vitreous lustre. Biaxial (+) n$_α$ = 1.579 n$_β$ = 1.588 n$_γ$ = 1.604 2V 63° to 77° Max birefringence δ = 0.025 |
| Volkovskite | KCa$_4$[B$_5$O$_8$OH]$_4$[B(OH)$_3$]$_2$Cl·4H$_2$O | | triclinic | P1 | a = 6.57, b = 23.92, c = 6.52 α = 90.58°, β = 119.1°, γ = 95.56° | 889.2 | 2.27 | Colourless or pink; varying from pale to deep orange crystals with a vitreous lustre. Biaxial (+) n$_α$ = 1.523 - 1.539 n$_β$ = 1.539 - 1.540 n$_γ$ = 1.596 - 1.605 2V 14.6° Max birefringence δ = 0.073 |
| Kurgantaite | CaSr[B$_5$O$_9$]Cl·H$_2$O | | triclinic | P1 | a = 6.5732, b = 6.4445, c = 6.3693, α = 60.995°, β = 61.257°, γ = 77.191° Z=1 | | 2.99 | Colourless to white crystals with a vitreous lustre. |
| Chambersite | (Mn$^{2+}$)$_3$(B$_7$O$_{13}$)Cl | | orthorhombic | Pca2$_1$ | a = 8.68, b = 8.68, c = 12.26 Z=4 | 924 | 3.49 | Colorless to deep purple crystals with a vitreous lustre. Biaxial (+) n$_α$ = 1.732 n$_β$ = 1.737 n$_γ$ = 1.744 2V 83° Max birefringence δ = 0.012 |
| Ericaite | (Fe$^{2+}$)$_3$(B$_7$O$_{13}$)Cl | | orthorhombic | | a = 8.58, b = 8.65, c = 12.17 | 903 | 3.17 - 3.27 | Red, green, purple, brown or black crystals. Biaxial (-) n$_α$ = 1.731 n$_β$ = 1.755 n$_γ$ = 1.755 Max birefringence δ = 0.024 |
| Congolite | (Fe$^{2+}$,Mg)$_3$[B$_7$O$_{13}$]Cl | | trigonal | R3c | a = 8.62, c = 21.05 | 1355 | 3.58 | Pale red or pink crystals. Uniaxial (-) n$_ω$ = 1.755 n$_ε$ = 1.731 Max birefringence δ = 0.024 |
| Trembathite | (Mg,Fe$^{2+}$)$_3$[B$_7$O$_{13}$]Cl | | trigonal | | a = 8.57, c = 20.99 | 1335 | 2.84 - 3.34 | Colourless to pale blue transparent crystals with a vitreous lustre. Uniaxial (-) n$_ω$ = 1.684 n$_ε$ = 1.668 Max birefringence δ = 0.016 |
| Bandylite | Cu$^{2+}$[B(OH)$_4$]Cl | | tetragonal | P4/nmm | a = 6.19 Å, c = 5.61 Z=2 | 214.9 | 2.81 | Deep blue crystals with greenish portions; cendre blue to Italian blue, becoming greener with atacamite inclusions, with a vitreous or pearly lustre. Uniaxial (-) n$_ω$ = 1.691 - 1.692 n$_ε$ = 1.640 - 1.641 Max birefringence δ = 0.051 |
| | Li$_3$B$_8$O$_{13}$Cl | 350.75 | Otrhorhombic | Pca2$_1$ | a=17.229 b=9.3827 c=6.6452 Z=4 | 1074.25 | 2.169 | birefringence 0.094 at 1064 nm |
| | Na$_4$[B$_6$O$_9$(OH)$_3$](H$_2$O)Cl | | Otrhorhombic | Pca2$_1$ | a=15.4867 b=8.6867 c=8.8551 Z=2 | 1191.3 | 2.260 | SHG 0.4 × KDP |
| | Mg$_3$B$_7$O$_{13}$Cl | 392.05 | orthorhombic | Pca2$_1$ | a=8.5319 b=8.5282 c=12.0730 Z=4 | 878.45 | 2.964 | NLO |
| | KZn$_2$BO$_3$Cl$_2$ | | trigonal | R32 | | | | NLO SHG 1.3 × KDP |
| | Ag$_4$B$_7$O$_{12}$Cl | 734.6 | triclinic | P1 | a=8.7394 b=8.7881 c=9.1381 α=65.625° β=77.269° γ=61.173° Z=2 | 562 | | |
| | RbZn$_2$BO$_3$Cl$_2$ | 345.92 | trigonal | R32 | a=4.965 c=27.21 | | | NLO SHG 1.17 × KDP |
| | Sn$_3$B$_3$O$_7$Cl | | orthorhombic | Pna2$_1$ | a=9.5239 b=7.5804 c=12.3065 Z=4 | 1825 | 4.007 | SHG 0.5 × of KDP |
| | Sn$_3$B$_{10}$O$_{17}$Cl$_2$ | | orthorhombic | Pbcn | a =19.1905 b=10.3893 c=8.5164 | | | UV cutoff 280 nm; birefringence 0.125 at 546 nm |
| | Ba$_6$BO$_3$Cl$_9$ | 1201.90 | monoclinic | P2$_1$/n | a=8.229 b=12.259 c=19.080 β=90.20 Z=4 | 1924.7 | 4.418 | colourless |
| | NaBa$_4$Al$_2$B$_8$O$_{18}$Cl$_3$ | | tetragonal | P4$_2$nm | a = 12.048, c = 6.817 | | | NLO |
| | NaBa$_4$(GaB$_4$O$_9$)$_2$Cl$_3$ | 1192.62 | tetragonal | P4$_2$nm | a=12.1033 c=6.8329 Z=2 | 1001.0 | 3.957 | SHG 1.5xKDP |
| | Rb$_4$Ba$_{2.5}$B$_{20}$O$_{34}$Cl | 1481.10 | triclinic | P1 | a=6.756 b=11.086 c=11.288 α=99.07° β=90.60° γ=100.38° Z=1 | 820.6 | 2.9965 | colourless |
| | La(BO$_2$)$_2$Cl | | triclinic | | | | | |
| | Cs$_2$La$_2$B$_{10}$O$_{17}$Cl$_4$ | 1065.54 | monoclinic | Cm | a=8.6904 b=20.92 c=6.4231 β =104.003 Z=2 | 1126.15 | 3.142 | SHG 2.1xKDP |
| | Ce(BO$_2$)$_2$Cl | | triclinic | P1 | a = 4.2174; b = 6.5763; c = 8.1221 α = 82, 152; β = 89, 206; γ = 72.048°; Z = 2 | | | |
| | Ce$_3$[BO$_3$]$_2$Cl$_3$ | | hexagonal | P6$_3$/m | a = 9.2008, c = 5.8079; Z = 2 | | | |
| | Pr(BO$_2$)$_2$Cl | | triclinic | | | | | |
| | Sm$_4$[B$_{16}$O$_{26}$(OH)$_4$(H$_2$O)$_3$Cl$_4$] | | | | | | | |
| | Eu$_4$[B$_{16}$O$_{26}$(OH)$_4$(H$_2$O)$_3$Cl$_4$] | | | | | | | |
| | Gd$_4$[B$_{16}$O$_{26}$(OH)$_4$(H$_2$O)$_3$Cl$_4$] | | | | | | | |
| | Pb$_6$BO$_4$Cl$_7$ | 1566 | triclinic | P1 | a=8.001 b=8.054 c=13.116 α=89.52 β=89.66 γ=69.942 | 793.9 | 6.551 | colourless |
| | Pu[B$_4$O$_6$(OH)$_2$Cl] | | monoclinic | Cc | a=6.4898 b=11.174 c=9.6183 β=105.15° | | | |
| | Pu$_2$[B$_{13}$O$_{19}$(OH)$_5$Cl$_2$(H$_2$O)$_3$] | | monoclinic | P2$_1$/n | a=8.0522 b=14.568 c=9.82 β=90.12° | | | |
| | Pu$_4$[B$_{16}$O$_{26}$(OH)$_4$(H$_2$O)$_3$Cl$_4$] | | | | | | | |
| | Am[B$_9$O$_{13}$(OH)$_4$]·H$_2$O | | monoclinic | P2$_1$/n | a=7.703Å b=16.688Å c=9.872 β=90.073° | | | |
| | Am$_4$[B$_{16}$O$_{26}$(OH)$_4$(H$_2$O)$_3$Cl$_4$] | | | | | | | |
| | Cm$_2$[B$_{14}$O$_{20}$(OH)$_7$(H$_2$O)$_2$Cl] | | monoclinic | P2$_1$/n | a=7.9561 b=14.212 c=9.836 β=90.013° | | | |
| | Cm$_4$[B$_{16}$O$_{26}$(OH)$_4$(H$_2$O)$_3$Cl$_4$] | | | | | | | |
| | Cf$_4$[B$_{16}$O$_{26}$(OH)$_4$(H$_2$O)$_3$Cl$_4$] | | | | | | | |