Related literature {#sec1}
==================

For further structural motifs and the luminescence properties of copper(I)iodide with substituted pyridine, see Cariati *et al.* ( 2005[@bb3]).  For the extinction correction, see: Becker & Coppens (1974[@bb1]). 

Experimental {#sec2}
============

 {#sec2.1}

### Crystal data {#sec2.1.1}

(C~12~H~28~N)~2~\[Cu~3.194~I~6~(C~5~H~5~N)~2~\]*M* *~r~* = 1495.3Triclinic,*a* = 8.8974 (2) Å*b* = 11.8076 (3) Å*c* = 12.2176 (2) Åα = 73.2442 (18)°β = 78.5398 (17)°γ = 81.4137 (18)°*V* = 1198.74 (5) Å^3^*Z* = 1Mo *K*α radiationμ = 5.29 mm^−1^*T* = 100 K0.47 × 0.17 × 0.13 mm

### Data collection {#sec2.1.2}

Oxford Diffraction Xcalibur3 diffractometer with a Sapphire-3 CCD detectorAbsorption correction: Gaussian (*CrysAlis RED*; Oxford Diffraction, 2008[@bb5]) *T* ~min~ = 0.209, *T* ~max~ = 0.62338326 measured reflections7574 independent reflections6526 reflections with *I* \> 3σ(*I*)*R* ~int~ = 0.020

### Refinement {#sec2.1.3}

*R*\[*F* ^2^ \> 2σ(*F* ^2^)\] = 0.023*wR*(*F* ^2^) = 0.068*S* = 1.027574 reflections219 parametersH-atom parameters constrainedΔρ~max~ = 1.05 e Å^−3^Δρ~min~ = −0.53 e Å^−3^

 {#d5e374}

Data collection: *CrysAlis CCD* (Oxford Diffraction, 2008[@bb5]); cell refinement: *CrysAlis RED* (Oxford Diffraction, 2008[@bb5]); data reduction: *CrysAlis RED*; program(s) used to solve structure: *SUPERFLIP* (Oszlányi & Sütő, 2004[@bb4]); program(s) used to refine structure: *JANA2000* (Petříček *et al.*,  2000[@bb6]); molecular graphics: *DIAMOND* (Brandenburg, 1999[@bb2]); software used to prepare material for publication: *JANA2000*. 

Supplementary Material
======================

Crystal structure: contains datablocks global, I. DOI: [10.1107/S1600536810010202/jh2137sup1.cif](http://dx.doi.org/10.1107/S1600536810010202/jh2137sup1.cif)

Structure factors: contains datablocks I. DOI: [10.1107/S1600536810010202/jh2137Isup2.hkl](http://dx.doi.org/10.1107/S1600536810010202/jh2137Isup2.hkl)

Additional supplementary materials: [crystallographic information](http://scripts.iucr.org/cgi-bin/sendsupfiles?jh2137&file=jh2137sup0.html&mime=text/html); [3D view](http://scripts.iucr.org/cgi-bin/sendcif?jh2137sup1&Qmime=cif); [checkCIF report](http://scripts.iucr.org/cgi-bin/paper?jh2137&checkcif=yes)

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: [JH2137](http://scripts.iucr.org/cgi-bin/sendsup?jh2137)). 

Financial support from the Swedish Research Council is gratefully acknowledged

Comment
=======

Due to the wide variation in molecular structure, halocuprates(I) exhibit a very interesting structural chemistry.  The most important factor to this structural diversity is the fact that Cu(I) can accept trigonal planar coordination, tetrahedral coordination as well as less defined intermediate arrangements.  The further linkage of these units, triangles by corner-sharing or edge-sharing, tetrahedra also by face sharing yields further structural flexibility.  Many different version of oligometric and polymeric species in Cu(I)X (X=Cl,Br, I) have been discovered in copper (I) halide based systems containing inflexible N- donor ligands.  Stoichiometry and connectivity are dependent on the size and the coordination number of the cation that participate in the structure.  The compound presented here 2\[(C~12~H~28~N)^+^ \[I~3~ Cu~1.597~ N C~5~ H~5~\]^-^ \] (I), is prepared from reaction between copper powder, copperoxide, tetra n-propylammoniumiodide, pyridine and hydroiodic acid.  The anion in (I) has a range of Cu--I distances \[ 2.5200 (3)--2.7752 (6) Å\] while the I--Cu--I angles spread over large range \[108.039 (16)--122.009 (14)°\].  One of the two independent Cu positions is clearly under-occupied (Cu2, occ ≈ 0.6).  This non-stoichiometry leads to local relaxations that can be seen as anomalously large and anisotropic thermal parameters on the surrounding I neighbours.  The compound is light yellow in color, and it is well known that Cu cannot attain the divalent oxidation state in direct contact with iodide, and therefore we conclude that all Cu is in the monovalent state.  The charge balance must instead be maintained by the protonation of either the pyridine unit or the Cu~4-x~I~6~ -cluster unit, a likely scenario since the synthesis is run at a low pH value. 

The attached pyridine unit is a typical pyridine with N--C and C--C ranges \[ 1.345 (3)--1.349 (3) Å and 1.359 (5)--1.398 (4)Å respectively\] The angle C--N--C is 119.2 (2)° while (N/)C--C--C the angles ranges \[ 118.4 (2)--120.8 (2)°\].  The cation is a regular tetra propylammonium ion with N--C and C--C distances range \[1.518 (3)--1.521 (3) Å and 1.516 (3)--1.542 (3)Å respectively\], and the C--N--C, (N/)C--C--C angels range between \[107.99 (16)--111.36 (15)° and 108.40 (19)--115.60 (18)°\]. 

Experimental {#experimental}
============

Copper powder (2.854 mmol), copper(I)oxide (2.827 mmol), hydroiodic acid (7.6 mmol) tetra n-propylammonium iodide (3.101 mmol) and pyridine (12.958 mmol) were put into an autoclave and heated at 165 °C for 19 h. It resulted in yellow crystals that luminesce vividly under UV light. 

Refinement {#refinement}
==========

The structures were solved by charge-flipping, giving the I, Cu, P and a major part of the C positions.  Subsequently the remaining C positions were found using difference Fourier analysis.  All non-hydrogen positions were refined using full matrix least squares.  The hydrogen atoms were located by geometrical methods and were allowed to ride, with C--H = 1.00 Å and *U*~eq~ = 1.2*U*~iso~(C). 

Figures
=======

![ Molecular structure with atom labelling scheme for the I---Cu-Pyridine anion and the tetrapropeylammonium cation in (I).  Non H atoms are shown as 50% probability displacement ellipsoids.](e-66-0m431-fig1){#Fap1}

Crystal data {#tablewrapcrystaldatalong}
============

  ------------------------------------------------- ----------------------------------------
  (C~12~H~28~N)~2~\[Cu~3.194~I~6~(C~5~H~5~N)~2~\]   *Z* = 1
  *M~r~* = 1495.3                                   *F*(000) = 708.8
  Triclinic, *P*1                                   *D*~x~ = 2.071 Mg m^−3^
  Hall symbol: -P 1                                 Mo *K*α radiation, λ = 0.71069 Å
  *a* = 8.8974 (2) Å                                Cell parameters from 27591 reflections
  *b* = 11.8076 (3) Å                               θ = 4.3--32.2°
  *c* = 12.2176 (2) Å                               µ = 5.29 mm^−1^
  α = 73.2442 (18)°                                 *T* = 100 K
  β = 78.5398 (17)°                                 Rodd, yellow
  γ = 81.4137 (18)°                                 0.47 × 0.17 × 0.13 mm
  *V* = 1198.74 (5) Å^3^                            
  ------------------------------------------------- ----------------------------------------

Data collection {#tablewrapdatacollectionlong}
===============

  ---------------------------------------------------------------------------- --------------------------------------
  Oxford Diffraction Xcalibur3 diffractometer with a Sapphire-3 CCD detector   7574 independent reflections
  Radiation source: Enhance (Mo) X-ray source                                  6526 reflections with *I* \> 3σ(*I*)
  graphite                                                                     *R*~int~ = 0.020
  Detector resolution: 16.5467 pixels mm^-1^                                   θ~max~ = 32.2°, θ~min~ = 4.3°
  ω scans                                                                      *h* = −13→13
  Absorption correction: gaussian (*CrysAlis RED*; Oxford Diffraction, 2008)   *k* = −17→17
  *T*~min~ = 0.209, *T*~max~ = 0.623                                           *l* = −18→18
  38326 measured reflections                                                   
  ---------------------------------------------------------------------------- --------------------------------------

Refinement {#tablewraprefinementdatalong}
==========

  ------------------------------------- ---------------------------------------------------------------------------------
  Refinement on *F*^2^                  Weighting scheme based on measured s.u.\'s *w* = 1/\[σ^2^(*I*) + 0.0025*I*^2^\]
  *R*\[*F*^2^ \> 2σ(*F*^2^)\] = 0.023   (Δ/σ)~max~ = 0.048
  *wR*(*F*^2^) = 0.068                  Δρ~max~ = 1.05 e Å^−3^
  *S* = 1.02                            Δρ~min~ = −0.53 e Å^−3^
  7574 reflections                      Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
  219 parameters                        Extinction coefficient: 2863
  H-atom parameters constrained         
  ------------------------------------- ---------------------------------------------------------------------------------

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å^2^) {#tablewrapcoords}
==================================================================================================

  ------ --------------- --------------- --------------- -------------------- -------------
         *x*             *y*             *z*             *U*~iso~\*/*U*~eq~   Occ. ( \<1)
  I1     0.975221 (18)   0.302248 (12)   0.020355 (12)   0.01742 (5)          
  I2     0.969321 (19)   0.432391 (12)   0.321865 (12)   0.01872 (5)          
  I3     1.283574 (19)   0.118445 (12)   0.272365 (13)   0.01893 (5)          
  Cu1    1.07925 (4)     0.28339 (3)     0.20757 (2)     0.01739 (9)          
  Cu2    0.91317 (6)     0.49932 (4)     0.10844 (4)     0.01871 (17)         0.5968 (16)
  N1a    0.8219 (2)      0.88100 (15)    0.30754 (15)    0.0131 (5)           
  C11    0.7234 (3)      0.96480 (18)    0.37333 (18)    0.0144 (6)           
  C12    0.7803 (3)      1.0861 (2)      0.3507 (2)      0.0222 (8)           
  C13    0.6638 (3)      1.1587 (2)      0.42004 (19)    0.0194 (7)           
  C21    0.7404 (3)      0.76914 (19)    0.33556 (19)    0.0154 (6)           
  C22    0.7369 (3)      0.69023 (19)    0.45874 (19)    0.0171 (7)           
  C23    0.6214 (3)      0.5995 (2)      0.4812 (2)      0.0210 (7)           
  C31    0.9801 (3)      0.85294 (18)    0.34363 (18)    0.0149 (6)           
  C32    1.0882 (3)      0.7620 (2)      0.29315 (19)    0.0174 (7)           
  C33    1.2416 (3)      0.7437 (2)      0.3369 (2)      0.0212 (8)           
  C41    0.8411 (3)      0.93675 (19)    0.17762 (17)    0.0155 (6)           
  C42    0.6926 (3)      0.9801 (3)      0.1284 (2)      0.0278 (9)           
  C43    0.7306 (3)      1.0288 (2)      −0.0044 (2)     0.0243 (8)           
  N2p    0.6819 (3)      0.53437 (19)    0.11898 (18)    0.0230 (7)           
  C1p    0.6020 (4)      0.4452 (2)      0.1892 (2)      0.0280 (9)           
  C2p    0.4469 (4)      0.4472 (2)      0.1989 (2)      0.0281 (9)           
  C3p    0.3675 (3)      0.5463 (3)      0.1331 (2)      0.0286 (9)           
  C4p    0.4470 (3)      0.6379 (2)      0.0616 (2)      0.0255 (8)           
  C5p    0.6058 (3)      0.6306 (2)      0.0556 (2)      0.0230 (8)           
  H111   0.709622        0.924955        0.458341        0.0172\*             
  H112   0.615337        0.975346        0.357609        0.0172\*             
  H121   0.788888        1.127677        0.266172        0.0267\*             
  H122   0.882603        1.075863        0.37637         0.0267\*             
  H131   0.700703        1.238077        0.407604        0.0233\*             
  H132   0.561853        1.169742        0.393671        0.0233\*             
  H133   0.652506        1.115708        0.504295        0.0233\*             
  H211   0.632751        0.791309        0.318782        0.0184\*             
  H212   0.788247        0.721678        0.279421        0.0184\*             
  H221   0.704259        0.740092        0.514669        0.0206\*             
  H222   0.841604        0.647834        0.467763        0.0206\*             
  H231   0.630117        0.539099        0.556794        0.0252\*             
  H232   0.514642        0.640855        0.484102        0.0252\*             
  H233   0.643691        0.559055        0.417381        0.0252\*             
  H311   1.030484        0.928078        0.324356        0.0178\*             
  H312   0.968261        0.826734        0.430099        0.0178\*             
  H321   1.106057        0.790999        0.206662        0.0209\*             
  H322   1.041211        0.684915        0.317545        0.0209\*             
  H331   1.307175        0.675529        0.313024        0.0255\*             
  H332   1.295805        0.817379        0.303006        0.0255\*             
  H333   1.222332        0.726026        0.423343        0.0255\*             
  H411   0.904564        0.879347        0.136488        0.0186\*             
  H412   0.907379        1.003709        0.156362        0.0186\*             
  H421   0.627616        0.912646        0.147852        0.0334\*             
  H422   0.635112        1.044646        0.162693        0.0334\*             
  H431   0.635019        1.06992         −0.035239       0.0292\*             
  H432   0.809874        1.086453        −0.024139       0.0292\*             
  H433   0.771582        0.96156         −0.039839       0.0292\*             
  H1p    0.659276        0.374425        0.236251        0.0336\*             
  H2p    0.391005        0.379349        0.251916        0.0337\*             
  H3p    0.253328        0.550155        0.13809         0.0343\*             
  H4p    0.391506        0.709479        0.014187        0.0306\*             
  H5p    0.664306        0.697485        0.003719        0.0276\*             
  ------ --------------- --------------- --------------- -------------------- -------------

Atomic displacement parameters (Å^2^) {#tablewrapadps}
=====================================

  ----- -------------- -------------- -------------- --------------- --------------- ---------------
        *U*^11^        *U*^22^        *U*^33^        *U*^12^         *U*^13^         *U*^23^
  I1    0.01901 (9)    0.01857 (7)    0.01591 (7)    −0.00176 (5)    −0.00510 (6)    −0.00505 (5)
  I2    0.02250 (10)   0.01667 (7)    0.01748 (7)    0.00238 (5)     −0.00558 (6)    −0.00593 (5)
  I3    0.02042 (9)    0.01691 (7)    0.02043 (7)    0.00264 (5)     −0.00814 (6)    −0.00554 (5)
  Cu1   0.01693 (16)   0.01716 (12)   0.01845 (13)   0.00008 (10)    −0.00438 (11)   −0.00525 (10)
  Cu2   0.0160 (3)     0.0189 (2)     0.0195 (2)     −0.00081 (17)   −0.00471 (19)   −0.00163 (17)
  N1a   0.0134 (10)    0.0132 (7)     0.0128 (7)     −0.0025 (6)     −0.0018 (7)     −0.0032 (6)
  C11   0.0146 (11)    0.0147 (8)     0.0134 (8)     −0.0022 (7)     0.0012 (7)      −0.0050 (7)
  C12   0.0211 (14)    0.0141 (9)     0.0298 (12)    −0.0046 (8)     0.0039 (10)     −0.0074 (8)
  C13   0.0239 (14)    0.0161 (9)     0.0188 (10)    −0.0013 (8)     −0.0012 (9)     −0.0073 (8)
  C21   0.0153 (12)    0.0148 (9)     0.0177 (9)     −0.0054 (8)     −0.0026 (8)     −0.0051 (7)
  C22   0.0209 (13)    0.0135 (9)     0.0175 (9)     −0.0043 (8)     −0.0041 (8)     −0.0029 (7)
  C23   0.0192 (13)    0.0158 (9)     0.0261 (11)    −0.0068 (8)     0.0024 (9)      −0.0042 (8)
  C31   0.0155 (12)    0.0140 (8)     0.0172 (9)     −0.0009 (7)     −0.0053 (8)     −0.0059 (7)
  C32   0.0170 (12)    0.0184 (9)     0.0186 (9)     −0.0001 (8)     −0.0039 (8)     −0.0077 (8)
  C33   0.0175 (13)    0.0243 (11)    0.0256 (11)    0.0025 (9)      −0.0080 (9)     −0.0116 (9)
  C41   0.0157 (12)    0.0179 (9)     0.0112 (8)     −0.0010 (8)     −0.0006 (8)     −0.0027 (7)
  C42   0.0184 (14)    0.0397 (14)    0.0193 (11)    0.0019 (11)     −0.0043 (10)    −0.0001 (10)
  C43   0.0270 (15)    0.0276 (12)    0.0154 (10)    −0.0001 (10)    −0.0048 (9)     −0.0014 (8)
  N2p   0.0187 (12)    0.0265 (10)    0.0237 (10)    0.0039 (8)      −0.0079 (8)     −0.0065 (8)
  C1p   0.0368 (17)    0.0232 (11)    0.0230 (11)    0.0038 (10)     −0.0124 (11)    −0.0030 (9)
  C2p   0.0383 (17)    0.0261 (12)    0.0217 (11)    −0.0126 (11)    −0.0096 (11)    −0.0013 (9)
  C3p   0.0220 (15)    0.0369 (14)    0.0267 (12)    −0.0053 (11)    −0.0081 (11)    −0.0042 (10)
  C4p   0.0203 (14)    0.0252 (11)    0.0268 (12)    0.0051 (9)      −0.0068 (10)    −0.0022 (9)
  C5p   0.0184 (13)    0.0252 (11)    0.0238 (11)    0.0023 (9)      −0.0056 (10)    −0.0047 (9)
  ----- -------------- -------------- -------------- --------------- --------------- ---------------

Geometric parameters (Å, °) {#tablewrapgeomlong}
===========================

  ---------------------- -------------- ------------------- -------------
  I1---Cu1               2.5737 (4)     C31---C32           1.515 (3)
  I1---Cu2               2.7752 (6)     C31---H311          1.000
  I2---Cu1               2.5223 (3)     C31---H312          1.000
  I2---Cu2               2.6239 (5)     C32---C33           1.526 (4)
  I3---Cu1               2.5200 (3)     C32---H321          1.000
  Cu1---Cu2              2.8208 (5)     C32---H322          1.000
  Cu2---N2p              2.023 (2)      C33---H331          1.000
  N1a---C11              1.521 (3)      C33---H332          1.000
  N1a---C21              1.521 (3)      C33---H333          1.000
  N1a---C31              1.520 (3)      C41---C42           1.518 (4)
  N1a---C41              1.518 (3)      C41---H411          1.000
  C11---C12              1.522 (3)      C41---H412          1.000
  C11---H111             1.000          C42---C43           1.542 (3)
  C11---H112             1.000          C42---H421          1.000
  C12---C13              1.527 (4)      C42---H422          1.000
  C12---H121             1.000          C43---H431          1.000
  C12---H122             1.000          C43---H432          1.000
  C13---H131             1.000          C43---H433          1.000
  C13---H132             1.000          N2p---C1p           1.345 (3)
  C13---H133             1.000          N2p---C5p           1.349 (3)
  C21---C22              1.522 (3)      C1p---C2p           1.359 (5)
  C21---H211             1.000          C1p---H1p           1.000
  C21---H212             1.000          C2p---C3p           1.398 (4)
  C22---C23              1.525 (4)      C2p---H2p           1.000
  C22---H221             1.000          C3p---C4p           1.368 (4)
  C22---H222             1.000          C3p---H3p           1.000
  C23---H231             1.000          C4p---C5p           1.391 (4)
  C23---H232             1.000          C4p---H4p           1.000
  C23---H233             1.000          C5p---H5p           1.000
                                                            
  Cu1---I1---Cu2         63.521 (13)    C22---C23---H233    109.5
  Cu1---I2---Cu2         66.443 (13)    H231---C23---H232   109.5
  I1---Cu1---I2          118.078 (12)   H231---C23---H233   109.5
  I1---Cu1---I3          119.911 (13)   H232---C23---H233   109.5
  I1---Cu1---Cu2         61.722 (14)    N1a---C31---C32     115.7 (2)
  I2---Cu1---I3          122.009 (14)   N1a---C31---H311    109.47
  I2---Cu1---Cu2         58.506 (13)    N1a---C31---H312    109.47
  I3---Cu1---Cu2         165.993 (17)   C32---C31---H311    109.47
  I1---Cu2---I2          108.039 (16)   C32---C31---H312    109.47
  I1---Cu2---Cu1         54.757 (12)    H311---C31---H312   102.4
  I1---Cu2---N2p         102.85 (8)     C31---C32---C33     109.6 (2)
  I1^i^---Cu2---I1       117.966 (18)   C31---C32---H321    109.47
  I1^i^---Cu2---I2       115.09 (2)     C31---C32---H322    109.5
  I1^i^---Cu2---Cu1      127.61 (2)     C33---C32---H321    109.5
  I1^i^---Cu2---Cu2^i^   61.601 (15)    C33---C32---H322    109.47
  I1^i^---Cu2---N2p      104.91 (6)     H321---C32---H322   109.4
  I1^i^---Cu2---C1p      130.33 (5)     C32---C33---H331    109.5
  I1^i^---Cu2---H1p      149.99 (2)     C32---C33---H332    109.5
  I2---Cu2---Cu1         55.051 (12)    C32---C33---H333    109.5
  I2---Cu2---Cu2^i^      135.09 (2)     H331---C33---H332   109.5
  I2---Cu2---N2p         106.60 (6)     H331---C33---H333   109.5
  Cu1---Cu2---N2p        127.48 (6)     H332---C33---H333   109.5
  C11---N1a---C21        107.99 (16)    N1a---C41---C42     115.60 (18)
  C11---N1a---C31        109.17 (19)    N1a---C41---H411    109.47
  C11---N1a---C41        111.12 (15)    N1a---C41---H412    109.5
  C21---N1a---C31        111.36 (15)    C42---C41---H411    109.5
  C21---N1a---C41        108.49 (19)    C42---C41---H412    109.47
  C31---N1a---C41        108.72 (16)    H411---C41---H412   102.6
  N1a---C11---C12        116.13 (18)    C41---C42---C43     109.5 (2)
  N1a---C11---H111       109.47         C41---C42---H421    109.5
  C12---C11---H112       109.47         C41---C42---H422    109.5
  H111---C11---H112      101.87         C43---C42---H421    109.5
  C11---C12---C13        108.40 (19)    C43---C42---H422    109.5
  C11---C12---H121       109.5          H421---C42---H422   109.4
  C11---C12---H122       109.47         C42---C43---H431    109.5
  C13---C12---H121       109.47         C42---C43---H432    109.5
  C13---C12---H122       109.5          C42---C43---H433    109.5
  H121---C12---H122      110.5          H431---C43---H432   109.5
  C12---C13---H131       109.5          H431---C43---H433   109.5
  C12---C13---H132       109.5          H432---C43---H433   109.5
  C12---C13---H133       109.47         Cu2---N2p---C1p     114.07 (17)
  H131---C13---H132      109.5          Cu2---N2p---C5p     126.45 (17)
  H131---C13---H133      109.5          C1p---N2p---C5p     119.2 (2)
  H132---C13---H133      109.5          N2p---C1p---C2p     122.8 (2)
  N1a---C21---C22        115.4 (2)      N2p---C1p---H1p     118.6
  N1a---C21---H211       109.47         C2p---C1p---H1p     118.6
  N1a---C21---H212       109.47         C1p---C2p---C3p     118.4 (2)
  C22---C21---H211       109.47         C1p---C2p---H2p     120.8
  C22---C21---H212       109.47         C3p---C2p---H2p     120.8
  H211---C21---H212      102.9          C2p---C3p---C4p     119.5 (3)
  C21---C22---C23        108.7 (2)      C2p---C3p---H3p     120.2
  C21---C22---H221       109.47         C4p---C3p---H3p     120.2
  C21---C22---H222       109.47         C3p---C4p---C5p     119.3 (2)
  C23---C22---H221       109.5          C3p---C4p---H4p     120.3
  C23---C22---H222       109.47         C5p---C4p---H4p     120.3
  H221---C22---H222      110.3          N2p---C5p---C4p     120.8 (2)
  C22---C23---H231       109.5          N2p---C5p---H5p     119.6
  C22---C23---H232       109.5          C4p---C5p---H5p     119.6
  ---------------------- -------------- ------------------- -------------

Symmetry codes: (i) −*x*+2, −*y*+1, −*z*.