Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536802016008/br6058sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536802016008/br6058Isup2.hkl |
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (O-N) = 0.004 Å
- R factor = 0.038
- wR factor = 0.106
- Data-to-parameter ratio = 20.0
checkCIF results
No syntax errors found ADDSYM reports no extra symmetry
The title compound was prepared by slow evaporation at room temperature of an approximately neutral aqueous solution containg dissolved HNO3, K2CrO4, KOH, ZrCl4 and Co(II)(OH)2. It formed yellow transparent thin platelets with indistinct to pseudohexagonal outline. The platelets were arranged in rosette-shaped to spheroidal aggregates, and accompanied by large prismatic to blocky crystals of yellow K2CrO4 [synthetic tarapacáite], minor colourless KNO3, and uninvestigated lilac grainy aggregates of a Co-compound.
Data collection: COLLECT (Nonius, 2002); cell refinement: HKL SCALEPACK (Otwinowski & Minor 1997); data reduction: HKL DENZO, SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ATOMS (Shape Software, 1999); ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).
CrK4N2O10 | F(000) = 776 |
Mr = 396.42 | Dx = 2.466 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 3227 reflections |
a = 10.143 (2) Å | θ = 2.0–30.0° |
b = 11.149 (2) Å | µ = 2.68 mm−1 |
c = 9.837 (2) Å | T = 293 K |
β = 106.31 (3)° | Thin platelet, pale yellow |
V = 1067.6 (4) Å3 | 0.20 × 0.10 × 0.01 mm |
Z = 4 |
Nonius KappaCCD diffractometer | 3107 independent reflections |
Radiation source: fine-focus sealed tube | 2139 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.027 |
ψ and ω scans | θmax = 30.1°, θmin = 2.1° |
Absorption correction: multi-scan (HKL SCALEPACK; Otwinowski & Minor, 1997) | h = −14→14 |
Tmin = 0.617, Tmax = 0.974 | k = −15→15 |
6048 measured reflections | l = −13→13 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.038 | w = 1/[σ2(Fo2) + (0.053P)2 + 0.430P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.106 | (Δ/σ)max < 0.001 |
S = 1.01 | Δρmax = 0.52 e Å−3 |
3107 reflections | Δρmin = −0.84 e Å−3 |
155 parameters | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.0020 (4) |
CrK4N2O10 | V = 1067.6 (4) Å3 |
Mr = 396.42 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 10.143 (2) Å | µ = 2.68 mm−1 |
b = 11.149 (2) Å | T = 293 K |
c = 9.837 (2) Å | 0.20 × 0.10 × 0.01 mm |
β = 106.31 (3)° |
Nonius KappaCCD diffractometer | 3107 independent reflections |
Absorption correction: multi-scan (HKL SCALEPACK; Otwinowski & Minor, 1997) | 2139 reflections with I > 2σ(I) |
Tmin = 0.617, Tmax = 0.974 | Rint = 0.027 |
6048 measured reflections |
R[F2 > 2σ(F2)] = 0.038 | 155 parameters |
wR(F2) = 0.106 | 0 restraints |
S = 1.01 | Δρmax = 0.52 e Å−3 |
3107 reflections | Δρmin = −0.84 e Å−3 |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. The structure is strongly hypercentric. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
K1 | 0.35921 (5) | 0.12280 (5) | 0.03356 (5) | 0.02566 (15) | |
K2 | 0.36336 (5) | 0.87896 (5) | 0.53445 (6) | 0.02938 (15) | |
K3 | 0.09503 (6) | 0.62574 (5) | 0.61292 (6) | 0.02560 (14) | |
K4 | 0.08402 (6) | 0.12720 (5) | 0.60806 (5) | 0.02717 (15) | |
Cr | 0.20415 (4) | 0.88240 (3) | 0.80931 (4) | 0.01722 (12) | |
N1 | 0.1539 (2) | 0.37197 (17) | 0.7980 (2) | 0.0214 (4) | |
N2 | 0.5070 (2) | 0.63781 (19) | 0.7679 (2) | 0.0261 (5) | |
O1 | 0.15608 (18) | 0.46875 (16) | 0.86197 (18) | 0.0296 (4) | |
O2 | 0.14715 (18) | 0.27453 (15) | 0.85857 (18) | 0.0287 (4) | |
O3 | 0.15162 (19) | 0.37247 (15) | 0.66926 (18) | 0.0291 (4) | |
O4 | 0.3974 (3) | 0.5874 (3) | 0.7275 (3) | 0.0819 (10) | |
O5 | 0.5486 (3) | 0.7099 (2) | 0.6946 (3) | 0.0620 (7) | |
O6 | 0.4216 (3) | 0.1246 (2) | 0.6065 (2) | 0.0508 (6) | |
O7 | 0.37171 (18) | 0.8941 (2) | 0.8475 (2) | 0.0433 (5) | |
O8 | 0.15907 (19) | 0.75791 (15) | 0.87380 (18) | 0.0291 (4) | |
O9 | 0.14067 (17) | 0.88209 (14) | 0.63575 (16) | 0.0242 (4) | |
O10 | 0.14221 (17) | 0.99815 (15) | 0.87589 (17) | 0.0238 (4) |
U11 | U22 | U33 | U12 | U13 | U23 | |
K1 | 0.0186 (3) | 0.0294 (3) | 0.0277 (3) | −0.0019 (2) | 0.0043 (2) | −0.0008 (2) |
K2 | 0.0246 (3) | 0.0332 (4) | 0.0318 (3) | −0.0004 (2) | 0.0104 (2) | 0.0011 (2) |
K3 | 0.0340 (3) | 0.0200 (3) | 0.0251 (3) | −0.0029 (2) | 0.0120 (2) | −0.0012 (2) |
K4 | 0.0404 (3) | 0.0192 (3) | 0.0209 (3) | 0.0034 (2) | 0.0070 (2) | 0.0002 (2) |
Cr | 0.0178 (2) | 0.0173 (2) | 0.01624 (19) | 0.00061 (14) | 0.00418 (13) | 0.00013 (14) |
N1 | 0.0272 (11) | 0.0188 (10) | 0.0193 (10) | −0.0031 (8) | 0.0085 (8) | −0.0013 (8) |
N2 | 0.0256 (12) | 0.0279 (12) | 0.0257 (11) | 0.0032 (8) | 0.0087 (9) | 0.0005 (9) |
O1 | 0.0378 (10) | 0.0202 (9) | 0.0297 (9) | −0.0037 (7) | 0.0078 (8) | −0.0067 (7) |
O2 | 0.0345 (10) | 0.0217 (9) | 0.0303 (10) | 0.0034 (7) | 0.0099 (8) | 0.0062 (7) |
O3 | 0.0356 (10) | 0.0304 (10) | 0.0254 (9) | −0.0005 (7) | 0.0153 (7) | 0.0007 (7) |
O4 | 0.0421 (15) | 0.102 (2) | 0.104 (2) | −0.0279 (15) | 0.0245 (15) | −0.0573 (19) |
O5 | 0.0910 (19) | 0.0566 (15) | 0.0531 (14) | 0.0181 (13) | 0.0442 (14) | 0.0178 (13) |
O6 | 0.0642 (15) | 0.0468 (14) | 0.0357 (12) | −0.0108 (10) | 0.0047 (11) | −0.0043 (10) |
O7 | 0.0157 (9) | 0.0647 (15) | 0.0466 (12) | −0.0019 (8) | 0.0039 (8) | −0.0052 (10) |
O8 | 0.0425 (11) | 0.0197 (9) | 0.0271 (9) | −0.0012 (7) | 0.0130 (8) | 0.0041 (7) |
O9 | 0.0275 (9) | 0.0261 (9) | 0.0181 (8) | −0.0003 (7) | 0.0049 (7) | −0.0016 (7) |
O10 | 0.0291 (9) | 0.0201 (9) | 0.0231 (8) | 0.0022 (6) | 0.0087 (7) | −0.0030 (7) |
K1—O7i | 2.657 (2) | K4—N1 | 3.271 (2) |
K1—O10ii | 2.6952 (18) | K4—N1iii | 3.319 (2) |
K1—O3iii | 2.7923 (19) | K4—Crxii | 3.3908 (9) |
K1—O5iv | 2.834 (2) | Cr—O7 | 1.6395 (19) |
K1—O2v | 2.8934 (19) | Cr—O8 | 1.6434 (17) |
K1—O6iii | 2.931 (2) | Cr—O9 | 1.6468 (16) |
K1—O4iii | 2.978 (3) | Cr—O10 | 1.6494 (16) |
K1—O7ii | 3.162 (2) | Cr—K4vii | 3.3908 (9) |
K1—O5i | 3.178 (3) | Cr—K3xiii | 3.4656 (10) |
K1—N2i | 3.360 (2) | Cr—K1xiv | 3.5461 (9) |
K1—Crii | 3.5461 (9) | Cr—K2xiii | 3.7409 (9) |
K1—K3iii | 4.0796 (9) | N1—O1 | 1.246 (2) |
K2—O8vi | 2.698 (2) | N1—O2 | 1.250 (2) |
K2—O9 | 2.7129 (18) | N1—O3 | 1.261 (3) |
K2—O5 | 2.811 (3) | N2—O4 | 1.209 (3) |
K2—O6vii | 2.849 (2) | N2—O5 | 1.231 (3) |
K2—O1vi | 2.8598 (19) | N2—O6xv | 1.253 (3) |
K2—O6i | 2.895 (3) | N2—K2xiii | 3.343 (2) |
K2—O7 | 3.061 (2) | O1—K2xiii | 2.8598 (19) |
K2—O4vi | 3.156 (3) | O1—K4xvi | 2.921 (2) |
K2—N2vi | 3.343 (2) | O1—K4x | 3.089 (2) |
K2—Cr | 3.5173 (10) | O2—K1xvii | 2.8934 (19) |
K2—Crvi | 3.7409 (9) | O2—K4xvi | 2.918 (2) |
K2—K2viii | 4.0600 (12) | O2—K3ix | 3.0416 (19) |
K3—O10ix | 2.8239 (18) | O3—K1xvi | 2.7923 (19) |
K3—O10vi | 2.8637 (18) | O3—K3xi | 3.172 (2) |
K3—O8 | 2.8710 (19) | O4—K1xvi | 2.978 (3) |
K3—O9 | 2.8939 (18) | O4—K2xiii | 3.156 (3) |
K3—O3 | 2.9037 (19) | O5—K1xviii | 2.834 (2) |
K3—O8vi | 2.9148 (19) | O5—K1i | 3.178 (3) |
K3—O1 | 2.932 (2) | O6—N2xix | 1.253 (3) |
K3—O4 | 2.986 (3) | O6—K2xii | 2.849 (2) |
K3—O2x | 3.0416 (19) | O6—K2i | 2.895 (3) |
K3—O3xi | 3.172 (2) | O6—K1xvi | 2.931 (2) |
K3—N1 | 3.327 (2) | O7—K1i | 2.657 (2) |
K3—Cr | 3.4560 (8) | O7—K1xiv | 3.162 (2) |
K4—O9xii | 2.7900 (17) | O8—K2xiii | 2.698 (2) |
K4—O9xi | 2.808 (2) | O8—K4x | 2.9125 (19) |
K4—O3 | 2.8422 (19) | O8—K3xiii | 2.9148 (19) |
K4—O2 | 2.8800 (19) | O9—K4vii | 2.7900 (17) |
K4—O8ix | 2.9125 (19) | O9—K4xi | 2.808 (2) |
K4—O10xii | 2.9131 (18) | O10—K1xiv | 2.6952 (18) |
K4—O2iii | 2.918 (2) | O10—K3x | 2.8239 (17) |
K4—O1iii | 2.921 (2) | O10—K3xiii | 2.8637 (18) |
K4—O1ix | 3.089 (2) | O10—K4vii | 2.9131 (18) |
O7i—K1—O10ii | 142.06 (6) | O10ix—K3—O1 | 69.45 (5) |
O7i—K1—O3iii | 127.59 (7) | O10vi—K3—O1 | 110.37 (5) |
O10ii—K1—O3iii | 71.41 (5) | O8—K3—O1 | 67.53 (5) |
O7i—K1—O5iv | 81.18 (8) | O9—K3—O1 | 122.21 (5) |
O10ii—K1—O5iv | 96.82 (7) | O3—K3—O1 | 43.61 (5) |
O3iii—K1—O5iv | 146.38 (7) | O8vi—K3—O1 | 153.81 (6) |
O7i—K1—O2v | 143.47 (6) | O10ix—K3—O4 | 135.17 (8) |
O10ii—K1—O2v | 66.96 (6) | O10vi—K3—O4 | 81.35 (7) |
O3iii—K1—O2v | 74.87 (5) | O8—K3—O4 | 77.61 (7) |
O5iv—K1—O2v | 71.57 (7) | O9—K3—O4 | 89.26 (7) |
O7i—K1—O6iii | 80.56 (7) | O3—K3—O4 | 70.23 (7) |
O10ii—K1—O6iii | 136.18 (6) | O8vi—K3—O4 | 86.00 (8) |
O3iii—K1—O6iii | 90.27 (6) | O1—K3—O4 | 69.25 (8) |
O5iv—K1—O6iii | 76.58 (7) | O10ix—K3—O2x | 63.39 (5) |
O2v—K1—O6iii | 69.95 (6) | O10vi—K3—O2x | 131.46 (5) |
O7i—K1—O4iii | 74.30 (8) | O8—K3—O2x | 67.88 (5) |
O10ii—K1—O4iii | 84.32 (8) | O9—K3—O2x | 64.53 (5) |
O3iii—K1—O4iii | 71.84 (7) | O3—K3—O2x | 129.37 (5) |
O5iv—K1—O4iii | 139.88 (8) | O8vi—K3—O2x | 101.57 (5) |
O2v—K1—O4iii | 141.49 (7) | O1—K3—O2x | 103.60 (6) |
O6iii—K1—O4iii | 128.25 (8) | O4—K3—O2x | 144.46 (6) |
O7i—K1—O7ii | 89.68 (6) | O10ix—K3—O3xi | 64.28 (5) |
O10ii—K1—O7ii | 53.85 (5) | O10vi—K3—O3xi | 64.00 (5) |
O3iii—K1—O7ii | 116.76 (5) | O8—K3—O3xi | 134.73 (5) |
O5iv—K1—O7ii | 75.06 (6) | O9—K3—O3xi | 97.55 (5) |
O2v—K1—O7ii | 105.73 (6) | O3—K3—O3xi | 103.78 (5) |
O6iii—K1—O7ii | 151.10 (6) | O8vi—K3—O3xi | 65.84 (5) |
O4iii—K1—O7ii | 73.57 (8) | O1—K3—O3xi | 131.64 (5) |
O7i—K1—O5i | 69.40 (7) | O4—K3—O3xi | 143.62 (7) |
O10ii—K1—O5i | 141.86 (6) | O2x—K3—O3xi | 67.57 (5) |
O3iii—K1—O5i | 70.71 (6) | O9xii—K4—O9xi | 98.21 (5) |
O5iv—K1—O5i | 112.38 (5) | O9xii—K4—O3 | 152.98 (6) |
O2v—K1—O5i | 98.70 (6) | O9xi—K4—O3 | 107.82 (5) |
O6iii—K1—O5i | 40.36 (6) | O9xii—K4—O2 | 119.01 (5) |
O4iii—K1—O5i | 88.17 (8) | O9xi—K4—O2 | 133.14 (5) |
O7ii—K1—O5i | 155.54 (6) | O3—K4—O2 | 44.57 (5) |
O8vi—K2—O9 | 68.95 (5) | O9xii—K4—O8ix | 129.70 (5) |
O8vi—K2—O5 | 103.39 (8) | O9xi—K4—O8ix | 64.71 (5) |
O9—K2—O5 | 107.30 (6) | O3—K4—O8ix | 70.34 (5) |
O8vi—K2—O6vii | 139.54 (6) | O2—K4—O8ix | 69.56 (5) |
O9—K2—O6vii | 91.84 (6) | O9xii—K4—O10xii | 56.23 (5) |
O5—K2—O6vii | 116.48 (8) | O9xi—K4—O10xii | 131.60 (5) |
O8vi—K2—O1vi | 70.89 (6) | O3—K4—O10xii | 107.94 (5) |
O9—K2—O1vi | 70.19 (5) | O2—K4—O10xii | 64.40 (5) |
O5—K2—O1vi | 174.22 (7) | O8ix—K4—O10xii | 98.73 (5) |
O6vii—K2—O1vi | 69.10 (6) | O9xii—K4—O2iii | 111.22 (5) |
O8vi—K2—O6i | 105.65 (6) | O9xi—K4—O2iii | 67.21 (5) |
O9—K2—O6i | 173.28 (6) | O3—K4—O2iii | 73.74 (5) |
O5—K2—O6i | 77.53 (7) | O2—K4—O2iii | 117.19 (3) |
O6vii—K2—O6i | 90.04 (7) | O8ix—K4—O2iii | 104.66 (6) |
O1vi—K2—O6i | 104.55 (6) | O10xii—K4—O2iii | 155.43 (5) |
O8vi—K2—O7 | 114.85 (6) | O9xii—K4—O1iii | 68.26 (5) |
O9—K2—O7 | 54.59 (5) | O9xi—K4—O1iii | 67.09 (5) |
O5—K2—O7 | 69.40 (6) | O3—K4—O1iii | 115.23 (5) |
O6vii—K2—O7 | 75.61 (6) | O2—K4—O1iii | 150.54 (6) |
O1vi—K2—O7 | 111.84 (6) | O8ix—K4—O1iii | 130.33 (6) |
O6i—K2—O7 | 132.12 (6) | O10xii—K4—O1iii | 122.30 (5) |
O8vi—K2—O4vi | 77.24 (7) | O2iii—K4—O1iii | 43.57 (5) |
O9—K2—O4vi | 132.52 (6) | O9xii—K4—O1ix | 64.96 (5) |
O5—K2—O4vi | 112.34 (7) | O9xi—K4—O1ix | 65.67 (5) |
O6vii—K2—O4vi | 93.04 (8) | O3—K4—O1ix | 132.83 (5) |
O1vi—K2—O4vi | 67.76 (6) | O2—K4—O1ix | 103.67 (6) |
O6i—K2—O4vi | 40.89 (7) | O8ix—K4—O1ix | 64.95 (5) |
O7—K2—O4vi | 167.46 (8) | O10xii—K4—O1ix | 66.18 (5) |
O10ix—K3—O10vi | 97.34 (5) | O2iii—K4—O1ix | 131.30 (5) |
O10ix—K3—O8 | 101.84 (6) | O1iii—K4—O1ix | 104.90 (5) |
O10vi—K3—O8 | 158.09 (6) | O7—Cr—O8 | 111.21 (10) |
O10ix—K3—O9 | 127.88 (5) | O7—Cr—O9 | 108.43 (10) |
O10vi—K3—O9 | 118.68 (5) | O8—Cr—O9 | 109.16 (9) |
O8—K3—O9 | 55.43 (5) | O7—Cr—O10 | 109.43 (10) |
O10ix—K3—O3 | 68.14 (5) | O8—Cr—O10 | 109.22 (9) |
O10vi—K3—O3 | 67.48 (5) | O9—Cr—O10 | 109.37 (8) |
O8—K3—O3 | 110.22 (5) | O1—N1—O2 | 120.52 (19) |
O9—K3—O3 | 157.95 (6) | O1—N1—O3 | 119.75 (19) |
O10ix—K3—O8vi | 129.87 (6) | O2—N1—O3 | 119.64 (19) |
O10vi—K3—O8vi | 55.35 (5) | O4—N2—O5 | 123.1 (3) |
O8—K3—O8vi | 116.56 (3) | O4—N2—O6xv | 119.5 (3) |
O9—K3—O8vi | 63.65 (5) | O5—N2—O6xv | 117.1 (2) |
O3—K3—O8vi | 120.65 (5) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, y−1, z−1; (iii) x, −y+1/2, z−1/2; (iv) −x+1, y−1/2, −z+1/2; (v) x, y, z−1; (vi) x, −y+3/2, z−1/2; (vii) x, y+1, z; (viii) −x+1, −y+2, −z+1; (ix) −x, y−1/2, −z+3/2; (x) −x, y+1/2, −z+3/2; (xi) −x, −y+1, −z+1; (xii) x, y−1, z; (xiii) x, −y+3/2, z+1/2; (xiv) x, y+1, z+1; (xv) −x+1, y+1/2, −z+3/2; (xvi) x, −y+1/2, z+1/2; (xvii) x, y, z+1; (xviii) −x+1, y+1/2, −z+1/2; (xix) −x+1, y−1/2, −z+3/2. |
Experimental details
Crystal data | |
Chemical formula | CrK4N2O10 |
Mr | 396.42 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 293 |
a, b, c (Å) | 10.143 (2), 11.149 (2), 9.837 (2) |
β (°) | 106.31 (3) |
V (Å3) | 1067.6 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 2.68 |
Crystal size (mm) | 0.20 × 0.10 × 0.01 |
Data collection | |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | Multi-scan (HKL SCALEPACK; Otwinowski & Minor, 1997) |
Tmin, Tmax | 0.617, 0.974 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6048, 3107, 2139 |
Rint | 0.027 |
(sin θ/λ)max (Å−1) | 0.705 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.038, 0.106, 1.01 |
No. of reflections | 3107 |
No. of parameters | 155 |
Δρmax, Δρmin (e Å−3) | 0.52, −0.84 |
Computer programs: COLLECT (Nonius, 2002), HKL SCALEPACK (Otwinowski & Minor 1997), HKL DENZO, SCALEPACK (Otwinowski & Minor, 1997), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 1997), ATOMS (Shape Software, 1999); ORTEP-3 for Windows (Farrugia, 1997).
K1—O7i | 2.657 (2) | K3—O1 | 2.932 (2) |
K1—O10ii | 2.6952 (18) | K3—O4 | 2.986 (3) |
K1—O3iii | 2.7923 (19) | K3—O2ix | 3.0416 (19) |
K1—O5iv | 2.834 (2) | K3—O3x | 3.172 (2) |
K1—O2v | 2.8934 (19) | K4—O9xi | 2.7900 (17) |
K1—O6iii | 2.931 (2) | K4—O9x | 2.808 (2) |
K1—O4iii | 2.978 (3) | K4—O3 | 2.8422 (19) |
K1—O7ii | 3.162 (2) | K4—O2 | 2.8800 (19) |
K1—O5i | 3.178 (3) | K4—O8viii | 2.9125 (19) |
K2—O8vi | 2.698 (2) | K4—O10xi | 2.9131 (18) |
K2—O9 | 2.7129 (18) | K4—O2iii | 2.918 (2) |
K2—O5 | 2.811 (3) | K4—O1iii | 2.921 (2) |
K2—O6vii | 2.849 (2) | K4—O1viii | 3.089 (2) |
K2—O1vi | 2.8598 (19) | Cr—O7 | 1.6395 (19) |
K2—O6i | 2.895 (3) | Cr—O8 | 1.6434 (17) |
K2—O7 | 3.061 (2) | Cr—O9 | 1.6468 (16) |
K2—O4vi | 3.156 (3) | Cr—O10 | 1.6494 (16) |
K3—O10viii | 2.8239 (18) | N1—O1 | 1.246 (2) |
K3—O10vi | 2.8637 (18) | N1—O2 | 1.250 (2) |
K3—O8 | 2.8710 (19) | N1—O3 | 1.261 (3) |
K3—O9 | 2.8939 (18) | N2—O4 | 1.209 (3) |
K3—O3 | 2.9037 (19) | N2—O5 | 1.231 (3) |
K3—O8vi | 2.9148 (19) | N2—O6xii | 1.253 (3) |
O7—Cr—O8 | 111.21 (10) | O1—N1—O2 | 120.52 (19) |
O7—Cr—O9 | 108.43 (10) | O1—N1—O3 | 119.75 (19) |
O8—Cr—O9 | 109.16 (9) | O2—N1—O3 | 119.64 (19) |
O7—Cr—O10 | 109.43 (10) | O4—N2—O5 | 123.1 (3) |
O8—Cr—O10 | 109.22 (9) | O4—N2—O6xii | 119.5 (3) |
O9—Cr—O10 | 109.37 (8) | O5—N2—O6xii | 117.1 (2) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, y−1, z−1; (iii) x, −y+1/2, z−1/2; (iv) −x+1, y−1/2, −z+1/2; (v) x, y, z−1; (vi) x, −y+3/2, z−1/2; (vii) x, y+1, z; (viii) −x, y−1/2, −z+3/2; (ix) −x, y+1/2, −z+3/2; (x) −x, −y+1, −z+1; (xi) x, y−1, z; (xii) −x+1, y+1/2, −z+3/2. |
We are currently investigating and classifying crystal structure types of both natural and synthetic kröhnkite [Na2Cu(SO4)2·2H2O]-type oxysalts and related compounds (Fleck et al., 2002a,b). In our recent research we have also included chromate compounds (Fleck and Kolitsch, 2002), which are environmentally important because of the toxicity of hexavalent chromium. The title compound, the first chromate(VI)-nitrate to be reported, was obtained as an unexpected by- product during synthesis from aqueous solutions at room temperature. Because it crystallized from an approximately neutral aqueous solution and was accompanied by the synthetic analogue of tarapacáite (naturally occurring K2CrO4), it might also occur in K-rich natural environments.
The asymmetric unit of K4(CrO4)(NO3)2 contains four K, one Cr, two N and ten O atoms, all located on general positions. The structure is characterized by isolated CrO4 tetrahedra and NO3 groups which are linked together by K atoms (Figs. 1, 2). The latter show a layered arrangement approximately parallel to the (001) plane (Fig. 1). The overall linkage is weak, and explains the low hardness and tenacity of the compound.
The K atoms show coordination numbers between eight and ten, with a grand mean K—O distance of 2.905 Å. The unique CrO4 tetrahedron, although isolated, shows a slight angular distortion, with O—Cr—O angles ranging from 108.43 (10) to 111.21 (10)°. The oxygen ligands of the N2O3 group, O4, O5 and, to a lesser extent, O6, show somewhat increased displacement parameters (unlike those of the N1O3 group), and therefore indicate slight positional disorder.
The chemical composition of the title compound makes it unique. However, it is chemically related to the following four alkali sulfate nitrates, all with unknown crystal structures: K(NH4)3(SO4)(NO3)2 (ICDD-PDF 20–853), K2(NH4)2(SO4)(NO3)2 (ICDD-PDF 20–852), K4H2(NO3)2(SO4)2 (Orlova et al., 1986; ICDD-PDF 39–722), and Na2CrO2F2(NO3)2 (Brown & Gard, 1973; ICDD-PDF 30–1179). The first two of these compounds might be isostructural with the title compound, if one considers their equivalent stoichiometries.