α-Cs₂Cr₃O₁₀

The title compound, dicaesium trichromium(VI) oxide, is the orthorhombic (space group Pbca) modification of Cs₂Cr₃O₁₀. The compound is isotypic with its NH₄ and Rb trichromate analogues. The structure contains discrete [Cr₃O₁₀]²⁻ anions [Cr—O—Cr = 136.58 (11) and 140.30 (12)°] linked via two non-equivalent irregularly 11-coordinated Cs⁺ cations [d_av(Cs—O) = 3.224 and 3.272 Å]. All atoms are in general positions.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](Cr-O) = 0.002 Å
• R factor = 0.019
• wR factor = 0.052
• Data-to-parameter ratio = 29.7

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.96
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ....        Cr1
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ....        Cr2
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ....        Cr3

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: COLLECT (Nonius, 2003); cell refinement: HKL SCALEPACK (Otwinowski & Minor 1997); data reduction: HKL DENZO (Otwinowski & Minor, 1997) and SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ATOMS (Shape Software, 1999); ORTEP-3 for Windows (Farrugia, 1997).

dicesium trichromium(VI) oxide

Crystal data

Cs2Cr3O10	F(000) = 2096
Mr = 581.82	Dx = 3.449 Mg m^−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 4564 reflections
a = 11.887 (2) Å	θ = 2.0–32.6°
b = 9.671 (2) Å	µ = 9.29 mm^−1
c = 19.493 (4) Å	T = 293 K
V = 2240.9 (8) Å^3	Tabular, orange
Z = 8	0.10 × 0.10 × 0.05 mm

Data collection

Nonius KappaCCD diffractometer	4071 independent reflections
Radiation source: fine-focus sealed tube	3587 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.011
ψ and ω scans	θmax = 32.6°, θmin = 2.7°
Absorption correction: multi-scan HKL SCALEPACK (Otwinowski & Minor, 1997)	h = −17→17
Tmin = 0.457, Tmax = 0.654	k = −14→14
7678 measured reflections	l = −29→29

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.019	w = 1/[σ^2(Fo^2) + (0.028P)^2 + 1.72P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.053	(Δ/σ)max = 0.002
S = 1.05	Δρmax = 0.59 e Å^−3
4071 reflections	Δρmin = −0.87 e Å^−3
137 parameters	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.00197 (7)

Special details

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. 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cs1	0.551246 (12)	0.646114 (15)	0.416422 (7)	0.02978 (5)
Cs2	0.225573 (12)	0.774086 (15)	0.320165 (8)	0.03163 (5)
Cr1	0.31124 (3)	0.50625 (4)	−0.024272 (17)	0.02531 (7)
Cr2	0.37664 (3)	0.69456 (4)	0.112922 (17)	0.02531 (7)
Cr3	0.49513 (3)	0.50362 (4)	0.232628 (18)	0.02427 (7)
O1	0.3544 (3)	0.3499 (2)	−0.02371 (13)	0.0629 (7)
O2	0.18390 (17)	0.5129 (2)	−0.05239 (11)	0.0441 (5)
O3	0.38996 (17)	0.6022 (2)	−0.07125 (10)	0.0439 (4)
O4	0.31084 (17)	0.5724 (2)	0.06318 (9)	0.0395 (4)
O5	0.28273 (17)	0.7574 (3)	0.16140 (11)	0.0491 (5)
O6	0.42874 (19)	0.8151 (2)	0.06763 (11)	0.0442 (4)
O7	0.48350 (16)	0.6242 (2)	0.16099 (9)	0.0368 (4)
O8	0.62195 (16)	0.5187 (2)	0.26009 (11)	0.0413 (4)
O9	0.40740 (15)	0.54400 (19)	0.29248 (9)	0.0345 (4)
O10	0.4713 (2)	0.34858 (19)	0.20758 (11)	0.0480 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cs1	0.03058 (8)	0.03135 (8)	0.02740 (7)	−0.00003 (5)	−0.00390 (5)	0.00029 (5)
Cs2	0.03385 (8)	0.02909 (8)	0.03193 (8)	0.00131 (5)	−0.00477 (5)	−0.00476 (5)
Cr1	0.03152 (17)	0.02517 (16)	0.01923 (15)	0.00092 (13)	−0.00251 (12)	−0.00123 (11)
Cr2	0.02894 (16)	0.02843 (16)	0.01856 (14)	−0.00166 (13)	−0.00057 (12)	−0.00149 (12)
Cr3	0.02743 (16)	0.02293 (15)	0.02244 (15)	−0.00145 (12)	0.00058 (12)	−0.00026 (11)
O1	0.100 (2)	0.0376 (11)	0.0507 (13)	0.0266 (12)	−0.0015 (13)	0.0015 (9)
O2	0.0371 (9)	0.0575 (12)	0.0377 (10)	−0.0115 (9)	−0.0107 (8)	0.0051 (9)
O3	0.0414 (10)	0.0545 (12)	0.0359 (9)	−0.0095 (9)	0.0059 (8)	0.0033 (9)
O4	0.0481 (10)	0.0456 (10)	0.0247 (8)	−0.0112 (9)	−0.0030 (7)	−0.0082 (7)
O5	0.0398 (11)	0.0665 (15)	0.0411 (11)	0.0041 (9)	0.0071 (8)	−0.0213 (10)
O6	0.0536 (11)	0.0353 (9)	0.0436 (11)	−0.0017 (9)	0.0020 (9)	0.0123 (8)
O7	0.0379 (9)	0.0442 (10)	0.0282 (8)	−0.0016 (8)	−0.0045 (7)	0.0089 (7)
O8	0.0302 (8)	0.0461 (10)	0.0476 (11)	0.0011 (8)	−0.0061 (7)	0.0127 (9)
O9	0.0373 (9)	0.0359 (9)	0.0304 (8)	−0.0005 (7)	0.0070 (7)	−0.0031 (7)
O10	0.0753 (14)	0.0296 (9)	0.0393 (10)	−0.0112 (9)	0.0108 (10)	−0.0103 (7)

Geometric parameters (Å, º)

Cs1—O1^i	3.084 (2)	Cs2—O2^ii	3.265 (2)
Cs1—O3^ii	3.108 (2)	Cs2—O10^vi	3.289 (2)
Cs1—O9	3.1203 (19)	Cs2—O8^i	3.366 (2)
Cs1—O10^i	3.1222 (19)	Cs2—O1^v	3.406 (3)
Cs1—O4^iii	3.192 (2)	Cs2—O10^i	3.714 (3)
Cs1—O6^iv	3.225 (2)	Cr1—O1	1.597 (2)
Cs1—O2^v	3.2479 (19)	Cr1—O3	1.605 (2)
Cs1—O6^ii	3.309 (2)	Cr1—O2	1.6111 (19)
Cs1—O5^iii	3.321 (2)	Cr1—O4	1.8209 (18)
Cs1—O2^iii	3.342 (2)	Cr2—O5	1.584 (2)
Cs1—O8	3.393 (2)	Cr2—O6	1.588 (2)
Cs2—O9^vi	3.0990 (19)	Cr2—O4	1.7168 (18)
Cs2—O3^ii	3.119 (2)	Cr2—O7	1.7190 (18)
Cs2—O9	3.1487 (18)	Cr3—O10	1.6021 (18)
Cs2—O8^vii	3.172 (2)	Cr3—O8	1.6063 (19)
Cs2—O5	3.173 (2)	Cr3—O9	1.6128 (17)
Cs2—O7^vii	3.2430 (19)	Cr3—O7	1.8243 (18)
O1—Cr1—O3	111.36 (13)	O6—Cr2—O7	107.79 (10)
O1—Cr1—O2	110.01 (14)	O4—Cr2—O7	111.84 (10)
O3—Cr1—O2	109.30 (11)	O10—Cr3—O8	110.63 (12)
O1—Cr1—O4	109.09 (11)	O10—Cr3—O9	109.45 (10)
O3—Cr1—O4	109.42 (10)	O8—Cr3—O9	110.10 (11)
O2—Cr1—O4	107.58 (10)	O10—Cr3—O7	110.57 (10)
O5—Cr2—O6	108.96 (13)	O8—Cr3—O7	105.56 (9)
O5—Cr2—O4	106.26 (11)	O9—Cr3—O7	110.48 (9)
O6—Cr2—O4	111.63 (11)	Cr2—O4—Cr1	140.30 (12)
O5—Cr2—O7	110.34 (11)	Cr2—O7—Cr3	136.58 (11)

Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (ii) x, −y+3/2, z+1/2; (iii) x+1/2, y, −z+1/2; (iv) −x+1, y−1/2, −z+1/2; (v) −x+1/2, −y+1, z+1/2; (vi) −x+1/2, y+1/2, z; (vii) x−1/2, y, −z+1/2.