Redetermination of metarossite, CaV⁵⁺₂O₆·2H₂O

The redetermination of metarossite, CaV⁵⁺₂O₆·2H₂O, based on modern single-crystal diffraction data confirms the previous study based on precession photographs, however, with the H atoms located and all atoms refined with anisotropic displacement parameters.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](V-O) = 0.002 Å
• R factor = 0.036
• wR factor = 0.076
• Data-to-parameter ratio = 18.4

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full value Low .      0.964 Note
PLAT031_ALERT_4_C Refined Extinction Parameter within Range ......      2.500 Sigma
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         42 Report
PLAT975_ALERT_2_C Check Calcd Residual Density  0.93A From      O7       0.51 eA-3
PLAT976_ALERT_2_C Check Calcd Residual Density  1.06A From      O4      -0.49 eA-3
PLAT976_ALERT_2_C Check Calcd Residual Density  1.00A From     Ow8      -0.45 eA-3
PLAT976_ALERT_2_C Check Calcd Residual Density  0.97A From      O1      -0.42 eA-3
PLAT976_ALERT_2_C Check Calcd Residual Density  0.88A From      O1      -0.41 eA-3

Alert level G
PLAT004_ALERT_5_G Polymeric Structure Found with Maximum Dimension          1 Info
PLAT042_ALERT_1_G Calc. and Reported MoietyFormula Strings  Differ     Please Check
PLAT154_ALERT_1_G The s.u.'s on the Cell Angles are Equal ..(Note)      0.004 Degree
PLAT199_ALERT_1_G Reported _cell_measurement_temperature ..... (K)        293 Check
PLAT200_ALERT_1_G Reported   _diffrn_ambient_temperature ..... (K)        293 Check
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          2 Note
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600         44 Note
PLAT933_ALERT_2_G Number of OMIT records in Embedded RES .........          2 Note

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   8 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   8 ALERT level G = General information/check it is not something unexpected

   4 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   6 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

---

Computing details

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: XtalDraw (Downs & Hall-Wallace, 2003); software used to prepare material for publication: publCIF (Westrip, 2010).

Calcium vanadium (V) oxide dihydrate

Crystal data

CaV2O6·2H2O	Z = 2
Mr = 273.99	F(000) = 268
Triclinic, P1	Dx = 2.814 Mg m^−3
a = 6.2059 (4) Å	Mo Kα radiation, λ = 0.71073 Å
b = 7.0635 (4) Å	Cell parameters from 1255 reflections
c = 7.7516 (5) Å	θ = 2.7–29.8°
α = 93.166 (4)°	µ = 3.68 mm^−1
β = 96.548 (4)°	T = 293 K
γ = 105.883 (4)°	Platy, pale yellow
V = 323.36 (4) Å^3	0.07 × 0.07 × 0.06 mm

Data collection

Bruker APEXII CCD area-detector diffractometer	1508 reflections with I > 2σ(I)
φ and ω scan	Rint = 0.037
Absorption correction: multi-scan (SADABS; Bruker, 2004)	θmax = 31.5°, θmin = 2.7°
Tmin = 0.669, Tmax = 0.746	h = −9→8
5576 measured reflections	k = −10→10
2075 independent reflections	l = −11→11

Refinement

Refinement on F^2	Hydrogen site location: difference Fourier map
Least-squares matrix: full	Only H-atom coordinates refined
R[F^2 > 2σ(F^2)] = 0.036	w = 1/[σ^2(Fo^2) + (0.0318P)^2 + 0.0696P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.076	(Δ/σ)max < 0.001
S = 1.01	Δρmax = 0.77 e Å^−3
2075 reflections	Δρmin = −0.58 e Å^−3
113 parameters	Extinction correction: SHELXL2014 (Sheldrick, 2015b), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.005 (2)

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

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

	x	y	z	Uiso*/Ueq
Ca	0.76199 (10)	0.46286 (9)	0.14933 (8)	0.01285 (14)
V1	0.44824 (9)	0.10219 (7)	0.33438 (6)	0.01068 (13)
V2	0.37329 (8)	0.58264 (7)	0.34629 (6)	0.01004 (13)
O1	0.4051 (4)	0.8480 (3)	0.4170 (3)	0.0137 (4)
O2	0.5250 (3)	0.3869 (3)	0.3867 (3)	0.0106 (4)
OW3	0.8519 (5)	0.7632 (4)	0.3671 (4)	0.0236 (6)
O4	0.1030 (3)	0.4726 (3)	0.3330 (3)	0.0157 (5)
O5	0.1896 (4)	0.0684 (3)	0.2322 (3)	0.0207 (5)
O6	0.6214 (4)	0.1115 (3)	0.1910 (3)	0.0232 (5)
O7	0.4308 (4)	0.5998 (3)	0.1408 (3)	0.0155 (5)
OW8	0.0045 (4)	0.7225 (3)	0.0059 (3)	0.0164 (5)
H1	0.937 (8)	0.747 (6)	0.444 (6)	0.040*
H2	0.900 (8)	0.856 (7)	0.332 (6)	0.040*
H3	0.078 (8)	0.808 (7)	0.066 (6)	0.040*
H4	−0.069 (7)	0.766 (6)	−0.073 (6)	0.040*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ca	0.0120 (3)	0.0142 (3)	0.0116 (3)	0.0024 (2)	0.0017 (2)	0.0017 (2)
V1	0.0140 (3)	0.0077 (2)	0.0094 (2)	0.00209 (19)	0.00032 (18)	0.00023 (18)
V2	0.0124 (2)	0.0082 (2)	0.0087 (2)	0.0026 (2)	−0.00078 (18)	−0.00002 (18)
O1	0.0216 (11)	0.0084 (10)	0.0098 (10)	0.0030 (9)	−0.0002 (8)	0.0005 (8)
O2	0.0116 (10)	0.0092 (10)	0.0109 (10)	0.0032 (8)	−0.0001 (8)	0.0002 (8)
OW3	0.0237 (13)	0.0201 (13)	0.0243 (14)	0.0026 (11)	0.0011 (10)	0.0030 (11)
O4	0.0131 (10)	0.0160 (11)	0.0162 (11)	0.0021 (9)	−0.0006 (8)	0.0013 (9)
O5	0.0211 (12)	0.0136 (11)	0.0232 (13)	0.0024 (9)	−0.0075 (9)	0.0003 (9)
O6	0.0347 (14)	0.0147 (11)	0.0204 (12)	0.0027 (11)	0.0151 (10)	0.0004 (9)
O7	0.0188 (11)	0.0170 (11)	0.0113 (10)	0.0064 (9)	0.0007 (8)	0.0020 (9)
OW8	0.0196 (13)	0.0132 (12)	0.0130 (11)	0.0005 (10)	−0.0014 (9)	0.0006 (9)

Geometric parameters (Å, º)

Ca—O7^i	2.381 (2)	V1—O1^iii	1.899 (2)
Ca—O4^ii	2.394 (2)	V1—O2	1.943 (2)
Ca—OW8^ii	2.441 (2)	V1—O1^iv	2.004 (2)
Ca—O6	2.448 (2)	V1—V1^v	3.1033 (10)
Ca—O2	2.476 (2)	V1—V2^iv	3.1187 (7)
Ca—O7	2.496 (2)	V2—O4	1.633 (2)
Ca—OW3	2.530 (3)	V2—O7	1.675 (2)
Ca—OW8^i	2.554 (2)	V2—O1	1.874 (2)
V1—O6	1.623 (2)	V2—O2	1.895 (2)
V1—O5	1.655 (2)	V2—O2^iv	2.075 (2)
O7^i—Ca—O4^ii	145.60 (8)	O6—Ca—OW8^i	71.80 (7)
O7^i—Ca—OW8^ii	79.03 (8)	O2—Ca—OW8^i	133.65 (7)
O4^ii—Ca—OW8^ii	84.88 (8)	O7—Ca—OW8^i	149.58 (7)
O7^i—Ca—O6	89.84 (8)	OW3—Ca—OW8^i	135.12 (8)
O4^ii—Ca—O6	88.49 (8)	O6—V1—O5	109.11 (13)
OW8^ii—Ca—O6	148.85 (8)	O6—V1—O1^iii	105.21 (11)
O7^i—Ca—O2	116.63 (7)	O5—V1—O1^iii	97.89 (11)
O4^ii—Ca—O2	93.49 (7)	O6—V1—O2	94.99 (10)
OW8^ii—Ca—O2	145.90 (8)	O5—V1—O2	97.89 (10)
O6—Ca—O2	64.79 (7)	O1^iii—V1—O2	148.57 (9)
O7^i—Ca—O7	72.07 (8)	O6—V1—O1^iv	114.83 (11)
O4^ii—Ca—O7	140.72 (7)	O5—V1—O1^iv	135.88 (11)
OW8^ii—Ca—O7	97.51 (8)	O1^iii—V1—O1^iv	74.72 (9)
O6—Ca—O7	106.65 (8)	O2—V1—O1^iv	75.01 (8)
O2—Ca—O7	63.17 (7)	O4—V2—O7	106.24 (11)
O7^i—Ca—OW3	131.12 (9)	O4—V2—O1	105.17 (10)
O4^ii—Ca—OW3	72.51 (9)	O7—V2—O1	100.84 (10)
OW8^ii—Ca—OW3	76.53 (8)	O4—V2—O2	106.81 (10)
O6—Ca—OW3	129.97 (8)	O7—V2—O2	93.48 (10)
O2—Ca—OW3	70.58 (8)	O1—V2—O2	139.47 (9)
O7—Ca—OW3	70.05 (8)	O4—V2—O2^iv	102.14 (10)
O7^i—Ca—OW8^i	77.53 (7)	O7—V2—O2^iv	151.38 (10)
O4^ii—Ca—OW8^i	69.34 (7)	O1—V2—O2^iv	74.79 (8)
OW8^ii—Ca—OW8^i	77.39 (8)	O2—V2—O2^iv	74.69 (9)

Symmetry codes: (i) −x+1, −y+1, −z; (ii) x+1, y, z; (iii) x, y−1, z; (iv) −x+1, −y+1, −z+1; (v) −x+1, −y, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
OW3—H1···O4^iv	0.78 (5)	2.37 (5)	2.965 (4)	133 (4)
OW3—H2···O5^vi	0.72 (4)	2.25 (5)	2.900 (3)	150 (5)
OW8—H3···O5^vii	0.75 (4)	2.09 (5)	2.810 (3)	162 (5)
OW8—H4···O5^viii	0.84 (4)	1.97 (5)	2.794 (3)	166 (4)

Symmetry codes: (iv) −x+1, −y+1, −z+1; (vi) x+1, y+1, z; (vii) x, y+1, z; (viii) −x, −y+1, −z.