Crystal structure of the Anderson-type hetero­polyoxometalate; K₂[H₇Cr^IIIMo₆O₂₄]·8H₂O: a redetermination revealing the position of the extra H atom in the polyanion

K₂[H₇Cr^IIIMo₆O₂₄]·8H₂O contains a symmetric hydrogen bond in which the H atom does not lie on a crystallographic centre of symmetry. The structure has been redetermined in order to locate the position of the seventh H atom.

Key indicators

• Single-crystal X-ray study
• T = 446 K
• Mean [sigma](Mo-O) = 0.002 Å
• R factor = 0.024
• wR factor = 0.064
• Data-to-parameter ratio = 13.4

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT222_ALERT_3_B Large Non-Solvent  H     Uiso(max)/Uiso(min) ...        8.0 Ratio

Author Response: Because of H5. H5 on the psudo centre of O5b between O16b (-x+1, -y, -y+1).

Alert level C
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.35 Report
PLAT303_ALERT_2_C Full Occupancy H-Atom  H5     with # Connections       2.00 Check

Author Response: 'Explain in the Abstract & Comment. H5 on the psudo-centre/not centre of O5b between O16b (-x+1, -y, -y+1).'

PLAT354_ALERT_3_C Short   O-H (X0.82,N0.98A) O1C    -   H1     ...       0.70 Ang.

Author Response: Because of short HY bonding.

PLAT354_ALERT_3_C Short   O-H (X0.82,N0.98A) O13C   -   H13    ...       0.70 Ang.

Author Response: Because of short HY bonding.

PLAT417_ALERT_2_C Short Inter D-H..H-D       H3     ..  H31A    ..       2.11 Ang.

Author Response: Because of short HY bonding.

PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         25 Report
PLAT913_ALERT_3_C Missing # of Very Strong Reflections in FCF ....          1 Note
PLAT971_ALERT_2_C Check Calcd Residual Density  1.25A From     O1C       1.57 eA-3
PLAT975_ALERT_2_C Check Calcd Residual Density  1.00A From    O26W       1.03 eA-3
PLAT975_ALERT_2_C Check Calcd Residual Density  0.92A From    O26W       0.74 eA-3
PLAT975_ALERT_2_C Check Calcd Residual Density  0.77A From    O26W       0.71 eA-3
PLAT976_ALERT_2_C Check Calcd Residual Density  1.06A From    O30W      -0.54 eA-3
PLAT976_ALERT_2_C Check Calcd Residual Density  0.42A From    O29W      -0.45 eA-3

Alert level G
PLAT002_ALERT_2_G Number of Distance or Angle Restraints on AtSite         26 Note
PLAT004_ALERT_5_G Polymeric Structure Found with Maximum Dimension          2 Info
PLAT005_ALERT_5_G No _iucr_refine_instructions_details  in the CIF     Please Do !
PLAT083_ALERT_2_G SHELXL Second Parameter in WGHT Unusually Large.       6.31 Why ?
PLAT154_ALERT_1_G The su's on the Cell Angles are Equal ..........    0.00100 Degree
PLAT860_ALERT_3_G Number of Least-Squares Restraints .............         17 Note
PLAT912_ALERT_4_G Missing # of FCF Reflections Above STh/L=  0.600          4 Note

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

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

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S1. Chemical context

This redetermined structure of a typical Anderson-type heteropolyoxometalate (Anderson, 1937), K₂[H₇Cr^IIIMo₆O₂₄]·8H₂O reveals the position of the extra or seventh H atom in the [HCr^III(OH)₆Mo₆O₁₈]^2- polyanion. This has not only an extra H atom but this atom also forms a very short hydrogen bond [2.461 (3) Å]; however, the H atom that contributes to the short hydrogen bond does not lie on a crystallographic centre of symmetry.

An example of a relatively short hydrogen bond in which the H atom does lie on a crystallographic centre of symmetry in an Anderson-type polyanion was reported in the polyoxometalate, viz. K₇[H_4.5α-PtMo₆O₂₄]₂·11H₂O (Lee et al., 2010). In this compound, the two polyanions form a dimer, viz. [(H_4.5PtMo₆O₂₄)₂]^7- via seven hydrogen bonds, viz. four µ₃-O—H···µ₁–O (terminal Mo═O atom), two µ₂-O—H···µ₂-O and one central/symmetric µ₃-O···H···µ₃-O. The H atom of the central hydrogen bond in the compound lies on a crystallographic centre of symmetry (space group P1 : 1/2, 0, 1/2) with a µ₃-O···H···µ₃-O (1) distance of 2.553 (3) Å. In this way, the hydrogen bond is symmetric, O···H···O, and the donor and acceptor cannot be distinguished. The dimerization of the polyanion by these hydrogen bonds is possible because the µ₃-O atoms in the polyanion are only partially protonated. The location of the H atom in the central µ₃-O···H···µ₃-O unit was determined from a centrosymmetric electron density map around the H-atom position. This centrosymmetric inter­pretation of the hydrogen bond is strongly supported by the bond-valence sums (BVS; Brown & Altermatt, 1985; Brese & O'Keeffe, 1991). The sum around the strongly bonded µ₃-O atom is 1.92 valence units (v.u.) in the [(H_4.5PtMo₆O₂₄)₂]^7- polyanion. The reasonable BVS values of very short or very long O—H bond distances can be obtained from the graphical correlation (Brown, 2001).

However, the title compound belongs to the B-series Anderson-type polyanions (Tsigdinos, 1978) viz. [Xⁿ⁺(OH)₆MoO₁₈]^(12-n)- (X = heteroatom), in which such dimerization is impossible, because all six µ₃-O atoms are fully protonated. The polyanion structure in the title compound is shown in Fig. 1.

S2. Structural commentary

This study was carried out to identify the position of the seventh or extra H atom in the [HCr^III(OH)₆Mo₆O₁₈]^2- polyanion. After considering the electron density maps and BVS values of the protonated OB (O-bridged µ₂-O atom) atoms in the previously reported structure (Lee, 2007), we considered that the positional disorder model of the H atom was wrong. The electron density (Fig. 2) is not symmetric in the title compound, but we expect the H atoms to lie in the middle of the bond because of the short O···O distance of 2.461 (3) Å, which corresponds to a pseudosymmetric hydrogen bond. The description of the rest of the structure and the composition of the atoms in the polyanion are the same as in the previous report of the compound, viz. K₂[H₇Cr^IIIMo₆O₂₄]·8H₂O (Lee, 2007). The O atoms of the polyoxometalate are designated as OT (terminal Mo═O atom), OB, and OC (centre of two Mo and one Cr atom, µ₃-O atom), respectively.

In the present case, the O5B···H5 and O16Bⁱ···H5 distances are both 1.23 Å (Table 1). This hydrogen bond is considered to be a symmetric hydrogen bond because the O5B···O16Bⁱ distance, 2.461 (3) Å, is very short. However, since the H atom does not lie on a crystallographic centre of symmetry, the present structure is considered to be particularly significant. As a result, the H5 atom is co-shared as O5B···H5···O16Bⁱ, and the average equation of the polyanion is [Cr^III(µ₃-OH)₆{µ₂-O(0.5H)}₂Mo₆O₁₇]^2-.

The calculated BVS for the O5B and O16B atoms are 1.59 and 1.57 v.u., respectively, if the valence of the O—H bond is not included. Since the BVS value around the µ₂-O atom should be 2.0 v.u., the missing valences of O5B and O16B are 0.41 and 0.43 v.u., respectively, corresponding to the valence of the O—H bonds. The obtained graphical correlation valence of H5 from its distance, 1.232 (7) Å, is 0.41 v.u., which is sufficient to satisfy the sums around the O5B and O16B atoms. As a result, the valence sums around O5B and O16B are 2.00 and 1.98 v.u., respectively. The BVS around the unprotonated µ₂-O atoms, viz. O4B, O6B, O17B and O18B are 1.98, 1.96, 2.13 and 2.02 v.u., respectively.

The positional disordered model in the previous report (Lee, 2007) showed unreasonable BVS values. The calculated BVS for the O5B and O16B atoms are 1.62 and 1.57 v.u., respectively, if the valence of the O—H bond is not included. The obtained graphical correlation valences of H5 and H16 from its distances [O5B—H5 = 0.71 (8), H5···O16B = 1.79 (8) Å and O16B—H16 = 0.83 (8), H16···O5B = 1.65 (8) Å] are 0.24 and 0.26 v.u. Therefore, the total BVS values of O5B and O16B are 1.86 and 1.83 v.u., respectively.

As a result, we consider that the present model of the title compound is reasonable, and the one extra H atom is located at the mid-point between the O5B and O16B atoms, and shared equally by two discrete polyanions. All H atoms and hydrogen bonds were well-defined in the title compound (Table 1).

S3. Supra­molecular features

Two discrete polyanions A and B are linked into chains along [011] by two normal, and one strong and pseudosymmetric hydrogen bonds (Table 1 and Fig.3). The K⁺ ions are variously coordinated by O atoms as [K1(OT)₄(OW)₄]⁺ and [K2(OT)₄(OB)(OW)₃]⁺ in the distance range 2.722 (3)–3.075 (3) Å. Furthermore, the polyanions are three dimensionally linked via clusters of K···OT, OB and OW inter­actions. All water molecules form hydrogen bonds with polyanions except for the O30W and O31W water molecules.

S4. Synthesis and crystallization

The crude potassium salt of title compound was obtained from the reaction of Na₃[H₆CrMo₆O₂₄].8H₂O (Perloff, 1970) solution and excess KCl solution. The title compound was obtained by recrystallization of crude K₃[H₆CrMo₆O₂₄].8H₂O at pH 1.80.

S5. Refinement

All the H atoms in the polyanions and all water H atoms were positioned using difference Fourier maps. All H atoms in the polyanion were refined freely, but the H5 atoms were refined with a distance restraint of O5B—H5 and O16Bⁱⁱⁱ—H5 (Table 1) using the SADI command in SHELXL97 (Sheldrick, 2008); σ = 0.01, the distances between the first and second named bonds were restrained to be equal with an effective standard deviation sigma in order to locate the H5 atom on the pseudocentre between the O5B and O16B atoms. The H atoms of all water molecules (OW) were refined with a distance restraint of O—H = 0.95 (3) Å using the DFIX command, and were included in the refinement with U_iso(H) = 1.5U_eq(O). The highest peak in the difference map is 1.62 Å from O9T.

Related literature

For related literature, see: Brese & O'Keeffe (1991); Brown & Altermatt (1985); Lee (2007); Lee & Joo (2004); Perloff (1970); Sheldrick (2008); Tsigdinos (1978).

Computing details

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012), PLATON (Spek, 2009) and DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The polyanion structure in the title compound. Displacement ellipsoids are drawn at the 50% probability level for non-H atoms. H atoms are shown as small spheres of arbitrary radius. [Symmetry codes: (i) -x + 1, -y, -z + 2; (ii) -x + 1, -y + 1, -z + 1.]
	Fig. 2. Difference Fourier map around atom H5 where atom H5 is absent.
	Fig. 3. Polyhedral view of the heteropolyanion in (I), with O···O contacts of the inter-polyanion hydrogen bonds shown as dashed lines. [Symmetry codes; (i) -x + 1, -y, -z + 1; (ii) x , y, z - 1; (iii) -x + 1, -y + 1, -z + 1; (iv) x, y + 1, z; (v) -x + 1, -y + 1, -z + 2.]

Dipotassium heptahydrogen hexamolybdochromate(III) octahydrate

Crystal data

K2[H7CrMo6O24]·8H2O	Z = 2
Mr = 1241.02	F(000) = 1186
Triclinic, P1	Dx = 2.968 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 10.4588 (2) Å	Cell parameters from 9896 reflections
b = 10.8553 (2) Å	θ = 2.5–33.5°
c = 12.6287 (3) Å	µ = 3.42 mm^−1
α = 99.296 (1)°	T = 446 K
β = 94.469 (1)°	Block, purple
γ = 99.283 (1)°	0.18 × 0.11 × 0.09 mm
V = 1388.44 (5) Å^3

Data collection

Bruker SMART APEXII CCD diffractometer	6028 independent reflections
Radiation source: Rotating Anode	5893 reflections with I > 2σ(I)
Graphite multilayer monochromator	Rint = 0.025
Detector resolution: 10.0 pixels mm^-1	θmax = 27.0°, θmin = 1.6°
ϕ and ω scans	h = −13→13
Absorption correction: multi-scan (SADABS; Sheldrick, 2008)	k = −13→13
Tmin = 0.645, Tmax = 0.746	l = −16→16
23489 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.024	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.064	w = 1/[σ^2(Fo^2) + (0.0255P)^2 + 6.3059P] where P = (Fo^2 + 2Fc^2)/3
S = 1.11	(Δ/σ)max = 0.001
6028 reflections	Δρmax = 1.58 e Å^−3
450 parameters	Δρmin = −0.67 e Å^−3
17 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.00391 (16)

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.

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 > 2sigma(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
Cr1	0.5000	0.0000	1.0000	0.00813 (15)
Cr2	0.5000	0.5000	0.5000	0.00762 (15)
Mo1	0.23267 (3)	0.13627 (3)	0.99546 (2)	0.01127 (8)
Mo2	0.20792 (3)	−0.17249 (3)	0.90598 (2)	0.01086 (8)
Mo3	0.47636 (3)	−0.31129 (3)	0.92212 (2)	0.01051 (8)
Mo4	0.79232 (3)	0.42389 (3)	0.46268 (2)	0.00994 (8)
Mo5	0.52144 (3)	0.19391 (3)	0.43518 (2)	0.00938 (8)
Mo6	0.23147 (3)	0.27465 (3)	0.46825 (2)	0.00952 (8)
K1	0.06894 (8)	0.02275 (9)	0.66878 (7)	0.02014 (17)
K2	0.92835 (8)	0.58495 (9)	0.77823 (7)	0.02212 (18)
O1C	0.4157 (2)	0.1138 (2)	1.0986 (2)	0.0113 (5)
H1	0.414 (6)	0.100 (5)	1.151 (5)	0.033 (16)*
O2C	0.3526 (2)	0.0070 (2)	0.8952 (2)	0.0099 (5)
H2	0.362 (5)	0.029 (5)	0.842 (4)	0.028 (14)*
O3C	0.3916 (2)	−0.1598 (2)	1.0194 (2)	0.0109 (5)
H3	0.386 (5)	−0.166 (5)	1.083 (5)	0.034 (15)*
O4B	0.1720 (2)	−0.0378 (2)	1.0107 (2)	0.0137 (5)
O5B	0.3370 (2)	−0.2592 (2)	0.83029 (19)	0.0121 (5)
H5	0.334 (9)	−0.271 (9)	0.7314 (10)	0.12 (3)*
O6B	0.6225 (2)	−0.2660 (2)	1.0259 (2)	0.0131 (5)
O7T	0.1329 (3)	0.1463 (3)	0.8855 (2)	0.0196 (6)
O8T	0.1748 (3)	0.2124 (3)	1.1047 (2)	0.0201 (6)
O9T	0.1160 (3)	−0.1627 (3)	0.7911 (2)	0.0171 (5)
O10T	0.1270 (3)	−0.2975 (3)	0.9535 (2)	0.0192 (6)
O11T	0.3862 (3)	−0.4281 (3)	0.9735 (2)	0.0184 (5)
O12T	0.5387 (3)	−0.3860 (2)	0.8119 (2)	0.0158 (5)
O13C	0.4147 (2)	0.3516 (2)	0.3922 (2)	0.0099 (5)
H13	0.415 (5)	0.359 (5)	0.338 (4)	0.015 (12)*
O14C	0.3526 (2)	0.4487 (2)	0.5815 (2)	0.0100 (5)
H14	0.357 (5)	0.437 (5)	0.643 (4)	0.019 (12)*
O15C	0.3920 (2)	0.6197 (2)	0.4556 (2)	0.0096 (5)
H15	0.376 (5)	0.616 (5)	0.395 (5)	0.034 (15)*
O16B	0.6638 (2)	0.2882 (2)	0.36714 (19)	0.0110 (5)
O17B	0.8278 (2)	0.5773 (2)	0.56733 (19)	0.0113 (5)
O18B	0.3755 (2)	0.1934 (2)	0.5151 (2)	0.0116 (5)
O19T	0.8822 (3)	0.4581 (3)	0.3615 (2)	0.0179 (5)
O20T	0.8741 (3)	0.3335 (3)	0.5323 (2)	0.0187 (6)
O21T	0.6089 (2)	0.1094 (3)	0.5064 (2)	0.0165 (5)
O22T	0.4583 (3)	0.0957 (2)	0.3159 (2)	0.0157 (5)
O23T	0.1361 (2)	0.2368 (3)	0.5654 (2)	0.0155 (5)
O24T	0.1681 (3)	0.1718 (3)	0.3527 (2)	0.0176 (5)
O25W	0.8716 (3)	0.0732 (3)	0.5305 (2)	0.0206 (6)
H25A	0.783 (3)	0.069 (5)	0.535 (4)	0.031*
H25B	0.891 (5)	0.159 (3)	0.530 (4)	0.031*
O26W	0.8483 (3)	0.0653 (3)	0.7784 (2)	0.0235 (6)
H26A	0.863 (5)	0.051 (5)	0.847 (3)	0.035*
H26B	0.827 (5)	−0.012 (3)	0.735 (4)	0.035*
O27W	0.3568 (3)	0.1168 (3)	0.7134 (2)	0.0261 (7)
H27A	0.367 (6)	0.113 (5)	0.643 (2)	0.039*
H27B	0.337 (6)	0.194 (3)	0.739 (4)	0.039*
O28W	0.6802 (3)	0.4221 (3)	0.7521 (2)	0.0208 (6)
H28A	0.629 (4)	0.464 (5)	0.794 (4)	0.031*
H28B	0.669 (5)	0.345 (3)	0.770 (4)	0.031*
O29W	0.8747 (4)	0.5437 (4)	0.9821 (3)	0.0390 (8)
H29A	0.810 (5)	0.479 (5)	0.998 (5)	0.059*
H29B	0.851 (6)	0.611 (5)	0.948 (5)	0.059*
O30W	0.0221 (5)	0.3490 (4)	0.7849 (5)	0.0640 (14)
H30A	−0.019 (9)	0.333 (9)	0.716 (4)	0.096*
H30B	−0.022 (8)	0.268 (4)	0.786 (7)	0.096*
O31W	0.3602 (3)	0.8223 (3)	0.2192 (2)	0.0206 (6)
H31A	0.295 (4)	0.868 (5)	0.226 (4)	0.031*
H31B	0.432 (4)	0.870 (4)	0.261 (4)	0.031*
O32W	0.3044 (3)	0.3645 (3)	0.7732 (2)	0.0245 (6)
H32A	0.219 (3)	0.366 (5)	0.772 (4)	0.037*
H32B	0.346 (5)	0.392 (5)	0.839 (3)	0.037*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cr1	0.0082 (3)	0.0076 (4)	0.0084 (3)	0.0010 (3)	0.0006 (3)	0.0013 (3)
Cr2	0.0070 (3)	0.0074 (4)	0.0086 (3)	0.0013 (3)	0.0009 (3)	0.0015 (3)
Mo1	0.01095 (14)	0.01186 (15)	0.01156 (14)	0.00390 (11)	0.00131 (11)	0.00177 (11)
Mo2	0.00957 (14)	0.01067 (15)	0.01165 (14)	0.00013 (11)	0.00034 (10)	0.00198 (11)
Mo3	0.01252 (14)	0.00810 (15)	0.01083 (14)	0.00194 (11)	0.00182 (11)	0.00109 (11)
Mo4	0.00749 (13)	0.00962 (15)	0.01315 (14)	0.00208 (10)	0.00177 (10)	0.00245 (11)
Mo5	0.00942 (14)	0.00756 (14)	0.01113 (14)	0.00169 (10)	0.00103 (10)	0.00138 (10)
Mo6	0.00820 (14)	0.00838 (15)	0.01158 (14)	0.00012 (10)	0.00090 (10)	0.00201 (11)
K1	0.0189 (4)	0.0248 (4)	0.0182 (4)	0.0039 (3)	0.0019 (3)	0.0081 (3)
K2	0.0173 (4)	0.0303 (5)	0.0177 (4)	0.0012 (3)	0.0017 (3)	0.0040 (3)
O1C	0.0135 (12)	0.0115 (12)	0.0089 (12)	0.0027 (9)	0.0016 (9)	0.0011 (10)
O2C	0.0108 (11)	0.0116 (12)	0.0081 (11)	0.0022 (9)	0.0019 (9)	0.0036 (9)
O3C	0.0135 (12)	0.0103 (12)	0.0093 (11)	0.0018 (9)	0.0017 (9)	0.0024 (9)
O4B	0.0130 (12)	0.0148 (13)	0.0135 (12)	0.0022 (10)	0.0041 (9)	0.0022 (10)
O5B	0.0127 (12)	0.0128 (12)	0.0106 (11)	0.0036 (9)	0.0005 (9)	0.0004 (9)
O6B	0.0144 (12)	0.0117 (12)	0.0129 (12)	0.0024 (10)	−0.0009 (9)	0.0026 (9)
O7T	0.0159 (13)	0.0214 (15)	0.0212 (14)	0.0031 (11)	−0.0022 (10)	0.0058 (11)
O8T	0.0206 (14)	0.0200 (14)	0.0203 (13)	0.0046 (11)	0.0066 (11)	0.0019 (11)
O9T	0.0168 (13)	0.0182 (14)	0.0157 (13)	0.0024 (11)	−0.0004 (10)	0.0028 (10)
O10T	0.0184 (13)	0.0168 (14)	0.0230 (14)	0.0013 (11)	0.0040 (11)	0.0062 (11)
O11T	0.0199 (13)	0.0145 (13)	0.0219 (13)	0.0023 (11)	0.0037 (11)	0.0063 (11)
O12T	0.0198 (13)	0.0140 (13)	0.0136 (12)	0.0047 (10)	0.0029 (10)	0.0002 (10)
O13C	0.0118 (12)	0.0104 (12)	0.0073 (12)	0.0014 (9)	0.0006 (9)	0.0019 (9)
O14C	0.0086 (11)	0.0130 (12)	0.0088 (11)	0.0014 (9)	0.0007 (9)	0.0039 (9)
O15C	0.0110 (11)	0.0096 (12)	0.0082 (11)	0.0019 (9)	−0.0002 (9)	0.0021 (9)
O16B	0.0122 (11)	0.0120 (12)	0.0083 (11)	0.0014 (9)	0.0033 (9)	0.0003 (9)
O17B	0.0103 (11)	0.0106 (12)	0.0124 (11)	0.0013 (9)	−0.0005 (9)	0.0022 (9)
O18B	0.0112 (11)	0.0106 (12)	0.0140 (12)	0.0022 (9)	0.0029 (9)	0.0045 (9)
O19T	0.0144 (12)	0.0169 (14)	0.0225 (14)	0.0003 (10)	0.0089 (10)	0.0031 (11)
O20T	0.0147 (13)	0.0159 (14)	0.0263 (14)	0.0055 (10)	−0.0019 (11)	0.0055 (11)
O21T	0.0127 (12)	0.0150 (13)	0.0240 (14)	0.0046 (10)	0.0028 (10)	0.0075 (11)
O22T	0.0162 (12)	0.0136 (13)	0.0156 (12)	0.0005 (10)	0.0014 (10)	0.0001 (10)
O23T	0.0139 (12)	0.0150 (13)	0.0187 (13)	0.0008 (10)	0.0049 (10)	0.0065 (10)
O24T	0.0165 (13)	0.0187 (14)	0.0168 (13)	0.0050 (11)	−0.0018 (10)	0.0005 (10)
O25W	0.0178 (13)	0.0182 (14)	0.0278 (15)	0.0071 (11)	0.0016 (11)	0.0062 (12)
O26W	0.0302 (16)	0.0238 (16)	0.0165 (13)	0.0047 (13)	0.0058 (12)	0.0023 (12)
O27W	0.0351 (17)	0.0310 (17)	0.0174 (14)	0.0118 (14)	0.0055 (12)	0.0121 (13)
O28W	0.0271 (15)	0.0180 (14)	0.0195 (14)	0.0085 (12)	0.0042 (11)	0.0050 (11)
O29W	0.040 (2)	0.040 (2)	0.043 (2)	0.0083 (16)	0.0114 (16)	0.0201 (17)
O30W	0.046 (3)	0.038 (2)	0.117 (4)	0.015 (2)	0.013 (3)	0.030 (3)
O31W	0.0258 (15)	0.0192 (15)	0.0157 (13)	0.0010 (12)	0.0010 (11)	0.0034 (11)
O32W	0.0257 (15)	0.0305 (17)	0.0152 (13)	−0.0007 (13)	0.0019 (12)	0.0036 (12)

Geometric parameters (Å, º)

Cr1—O1C^i	1.970 (2)	Mo6—O18B	1.964 (2)
Cr1—O1C	1.970 (3)	Mo6—O14C	2.301 (2)
Cr1—O2C	1.971 (2)	Mo6—O13C	2.307 (3)
Cr1—O2C^i	1.971 (2)	K1—O25W^iii	2.722 (3)
Cr1—O3C^i	1.975 (2)	K1—O25W^iv	2.778 (3)
Cr1—O3C	1.975 (2)	K1—O9T	2.809 (3)
Cr2—O13C^ii	1.970 (2)	K1—O7T	2.825 (3)
Cr2—O13C	1.970 (2)	K1—O26W^iv	2.844 (3)
Cr2—O15C	1.972 (2)	K1—O23T	2.862 (3)
Cr2—O15C^ii	1.972 (2)	K1—O24T^v	2.950 (3)
Cr2—O14C^ii	1.976 (2)	K1—O27W	2.997 (3)
Cr2—O14C	1.976 (2)	K2—O29W	2.767 (4)
Mo1—O8T	1.696 (3)	K2—O17B	2.769 (3)
Mo1—O7T	1.699 (3)	K2—O19T^vi	2.799 (3)
Mo1—O4B	1.939 (3)	K2—O8T^vii	2.855 (3)
Mo1—O6B^i	1.962 (3)	K2—O28W	2.858 (3)
Mo1—O1C	2.299 (3)	K2—O10T^viii	2.891 (3)
Mo1—O2C	2.321 (2)	K2—O30W^ix	2.897 (4)
Mo2—O10T	1.701 (3)	K2—O9T^viii	3.074 (3)
Mo2—O9T	1.705 (3)	O1C—H1	0.70 (6)
Mo2—O4B	1.913 (3)	O2C—H2	0.76 (6)
Mo2—O5B	1.986 (2)	O3C—H3	0.82 (6)
Mo2—O3C	2.276 (2)	O5B—O16B^iii	2.461 (3)
Mo2—O2C	2.296 (3)	O5B—H5	1.232 (7)
Mo3—O11T	1.701 (3)	O13C—H13	0.70 (5)
Mo3—O12T	1.722 (3)	O14C—H14	0.81 (5)
Mo3—O6B	1.879 (2)	O15C—H15	0.76 (6)
Mo3—O5B	2.001 (2)	O16B—H5^iii	1.231 (7)
Mo3—O3C	2.233 (2)	O25W—H25A	0.92 (3)
Mo3—O1C^i	2.321 (3)	O25W—H25B	0.93 (3)
Mo4—O19T	1.698 (3)	O26W—H26A	0.91 (3)
Mo4—O20T	1.702 (3)	O26W—H26B	0.91 (3)
Mo4—O17B	1.916 (2)	O27W—H27A	0.90 (3)
Mo4—O16B	1.992 (2)	O27W—H27B	0.91 (3)
Mo4—O15C^ii	2.275 (2)	O28W—H28A	0.91 (3)
Mo4—O14C^ii	2.306 (2)	O28W—H28B	0.90 (3)
Mo5—O21T	1.703 (3)	O29W—H29A	0.95 (3)
Mo5—O22T	1.715 (3)	O29W—H29B	0.96 (3)
Mo5—O18B	1.894 (2)	O30W—H30A	0.92 (3)
Mo5—O16B	1.998 (2)	O30W—H30B	0.93 (3)
Mo5—O15C^ii	2.264 (2)	O31W—H31A	0.90 (3)
Mo5—O13C	2.301 (2)	O31W—H31B	0.92 (3)
Mo6—O23T	1.700 (3)	O32W—H32A	0.89 (3)
Mo6—O24T	1.703 (3)	O32W—H32B	0.89 (3)
Mo6—O17B^ii	1.919 (2)
O1C^i—Cr1—O1C	180.00 (13)	O23T—Mo6—O24T	106.46 (13)
O1C^i—Cr1—O2C	96.36 (11)	O23T—Mo6—O17B^ii	102.39 (12)
O1C—Cr1—O2C	83.64 (10)	O24T—Mo6—O17B^ii	98.17 (12)
O1C^i—Cr1—O2C^i	83.64 (10)	O23T—Mo6—O18B	95.85 (11)
O1C—Cr1—O2C^i	96.36 (11)	O24T—Mo6—O18B	100.31 (12)
O2C—Cr1—O2C^i	180.000 (1)	O17B^ii—Mo6—O18B	149.10 (10)
O1C^i—Cr1—O3C^i	96.40 (11)	O23T—Mo6—O14C	92.72 (11)
O1C—Cr1—O3C^i	83.60 (11)	O24T—Mo6—O14C	160.17 (11)
O2C—Cr1—O3C^i	96.11 (10)	O17B^ii—Mo6—O14C	72.22 (9)
O2C^i—Cr1—O3C^i	83.89 (10)	O18B—Mo6—O14C	82.29 (10)
O1C^i—Cr1—O3C	83.60 (11)	O23T—Mo6—O13C	158.88 (11)
O1C—Cr1—O3C	96.40 (11)	O24T—Mo6—O13C	92.55 (11)
O2C—Cr1—O3C	83.89 (10)	O17B^ii—Mo6—O13C	83.47 (10)
O2C^i—Cr1—O3C	96.11 (10)	O18B—Mo6—O13C	71.21 (9)
O3C^i—Cr1—O3C	180.0	O14C—Mo6—O13C	69.50 (9)
O13C^ii—Cr2—O13C	180.00 (11)	O25W^iii—K1—O25W^iv	76.62 (9)
O13C^ii—Cr2—O15C	83.38 (10)	O25W^iii—K1—O9T	103.15 (9)
O13C—Cr2—O15C	96.62 (10)	O25W^iv—K1—O9T	139.32 (9)
O13C^ii—Cr2—O15C^ii	96.62 (10)	O25W^iii—K1—O7T	153.61 (9)
O13C—Cr2—O15C^ii	83.38 (10)	O25W^iv—K1—O7T	123.85 (9)
O15C—Cr2—O15C^ii	180.00 (14)	O9T—K1—O7T	72.86 (8)
O13C^ii—Cr2—O14C^ii	83.45 (11)	O25W^iii—K1—O26W^iv	140.01 (9)
O13C—Cr2—O14C^ii	96.55 (10)	O25W^iv—K1—O26W^iv	68.70 (9)
O15C—Cr2—O14C^ii	96.19 (10)	O9T—K1—O26W^iv	91.09 (9)
O15C^ii—Cr2—O14C^ii	83.81 (10)	O7T—K1—O26W^iv	66.28 (8)
O13C^ii—Cr2—O14C	96.55 (10)	O25W^iii—K1—O23T	74.25 (8)
O13C—Cr2—O14C	83.45 (11)	O25W^iv—K1—O23T	64.14 (8)
O15C—Cr2—O14C	83.81 (10)	O9T—K1—O23T	156.00 (8)
O15C^ii—Cr2—O14C	96.19 (10)	O7T—K1—O23T	98.65 (8)
O14C^ii—Cr2—O14C	180.000 (1)	O26W^iv—K1—O23T	106.24 (9)
O8T—Mo1—O7T	106.84 (14)	O25W^iii—K1—O24T^v	91.73 (9)
O8T—Mo1—O4B	99.43 (12)	O25W^iv—K1—O24T^v	68.54 (8)
O7T—Mo1—O4B	100.45 (12)	O9T—K1—O24T^v	70.82 (8)
O8T—Mo1—O6B^i	101.16 (12)	O7T—K1—O24T^v	110.61 (8)
O7T—Mo1—O6B^i	96.54 (12)	O26W^iv—K1—O24T^v	57.72 (8)
O4B—Mo1—O6B^i	148.14 (11)	O23T—K1—O24T^v	132.52 (8)
O8T—Mo1—O1C	91.58 (12)	O25W^iii—K1—O27W	83.91 (9)
O7T—Mo1—O1C	160.03 (12)	O25W^iv—K1—O27W	134.40 (9)
O4B—Mo1—O1C	83.63 (10)	O9T—K1—O27W	84.97 (8)
O6B^i—Mo1—O1C	71.79 (10)	O7T—K1—O27W	69.83 (8)
O8T—Mo1—O2C	159.33 (12)	O26W^iv—K1—O27W	135.05 (9)
O7T—Mo1—O2C	93.25 (12)	O23T—K1—O27W	71.05 (8)
O4B—Mo1—O2C	71.53 (10)	O24T^v—K1—O27W	153.77 (8)
O6B^i—Mo1—O2C	80.83 (10)	O29W—K2—O17B	146.30 (10)
O1C—Mo1—O2C	69.32 (9)	O29W—K2—O19T^vi	137.95 (10)
O10T—Mo2—O9T	105.54 (13)	O17B—K2—O19T^vi	70.05 (8)
O10T—Mo2—O4B	98.88 (12)	O29W—K2—O8T^vii	67.52 (10)
O9T—Mo2—O4B	104.05 (12)	O17B—K2—O8T^vii	102.90 (8)
O10T—Mo2—O5B	98.79 (12)	O19T^vi—K2—O8T^vii	140.83 (9)
O9T—Mo2—O5B	95.15 (11)	O29W—K2—O28W	73.32 (10)
O4B—Mo2—O5B	149.26 (11)	O17B—K2—O28W	74.70 (8)
O10T—Mo2—O3C	93.09 (11)	O19T^vi—K2—O28W	121.69 (9)
O9T—Mo2—O3C	157.67 (11)	O8T^vii—K2—O28W	91.06 (9)
O4B—Mo2—O3C	84.69 (10)	O29W—K2—O10T^viii	63.77 (10)
O5B—Mo2—O3C	69.42 (9)	O17B—K2—O10T^viii	147.47 (8)
O10T—Mo2—O2C	161.78 (11)	O19T^vi—K2—O10T^viii	91.15 (8)
O9T—Mo2—O2C	92.28 (11)	O8T^vii—K2—O10T^viii	74.69 (8)
O4B—Mo2—O2C	72.55 (10)	O28W—K2—O10T^viii	137.05 (8)
O5B—Mo2—O2C	83.06 (10)	O29W—K2—O30W^ix	79.00 (15)
O3C—Mo2—O2C	70.46 (9)	O17B—K2—O30W^ix	107.05 (14)
O11T—Mo3—O12T	106.13 (13)	O19T^vi—K2—O30W^ix	66.13 (12)
O11T—Mo3—O6B	100.61 (12)	O8T^vii—K2—O30W^ix	146.33 (14)
O12T—Mo3—O6B	102.43 (12)	O28W—K2—O30W^ix	82.43 (11)
O11T—Mo3—O5B	100.44 (12)	O10T^viii—K2—O30W^ix	87.75 (13)
O12T—Mo3—O5B	92.82 (11)	O29W—K2—O9T^viii	110.89 (10)
O6B—Mo3—O5B	149.33 (11)	O17B—K2—O9T^viii	94.26 (7)
O11T—Mo3—O3C	92.56 (11)	O19T^vi—K2—O9T^viii	72.19 (8)
O12T—Mo3—O3C	156.92 (11)	O8T^vii—K2—O9T^viii	69.98 (8)
O6B—Mo3—O3C	86.90 (10)	O28W—K2—O9T^viii	155.67 (8)
O5B—Mo3—O3C	70.11 (9)	O10T^viii—K2—O9T^viii	53.95 (7)
O11T—Mo3—O1C^i	161.82 (11)	O30W^ix—K2—O9T^viii	121.81 (11)
O12T—Mo3—O1C^i	91.92 (11)	Cr1—O1C—Mo1	103.93 (11)
O6B—Mo3—O1C^i	72.66 (10)	Cr1—O1C—Mo3^i	101.37 (11)
O5B—Mo3—O1C^i	80.47 (10)	Mo1—O1C—Mo3^i	91.53 (9)
O3C—Mo3—O1C^i	70.51 (9)	Cr1—O2C—Mo2	102.54 (11)
O19T—Mo4—O20T	106.50 (14)	Cr1—O2C—Mo1	103.10 (10)
O19T—Mo4—O17B	104.09 (12)	Mo2—O2C—Mo1	92.00 (9)
O20T—Mo4—O17B	98.21 (12)	Cr1—O3C—Mo3	104.32 (11)
O19T—Mo4—O16B	94.09 (12)	Cr1—O3C—Mo2	103.08 (11)
O20T—Mo4—O16B	99.92 (12)	Mo3—O3C—Mo2	97.93 (10)
O17B—Mo4—O16B	149.41 (10)	Mo2—O4B—Mo1	119.12 (13)
O19T—Mo4—O15C^ii	156.61 (11)	Mo2—O5B—Mo3	117.13 (12)
O20T—Mo4—O15C^ii	93.29 (11)	Mo2—O5B—O16B^iii	121.72 (12)
O17B—Mo4—O15C^ii	84.78 (10)	Mo3—O5B—O16B^iii	121.01 (12)
O16B—Mo4—O15C^ii	69.81 (9)	Mo3—O6B—Mo1^i	118.98 (13)
O19T—Mo4—O14C^ii	91.56 (11)	Cr2—O13C—Mo5	102.58 (10)
O20T—Mo4—O14C^ii	161.32 (12)	Cr2—O13C—Mo6	103.49 (11)
O17B—Mo4—O14C^ii	72.15 (9)	Mo5—O13C—Mo6	92.48 (9)
O16B—Mo4—O14C^ii	83.13 (9)	Cr2—O14C—Mo6	103.53 (11)
O15C^ii—Mo4—O14C^ii	70.30 (9)	Cr2—O14C—Mo4^ii	102.33 (10)
O21T—Mo5—O22T	106.65 (13)	Mo6—O14C—Mo4^ii	91.61 (8)
O21T—Mo5—O18B	99.32 (12)	Cr2—O15C—Mo5^ii	103.82 (10)
O22T—Mo5—O18B	102.90 (12)	Cr2—O15C—Mo4^ii	103.53 (10)
O21T—Mo5—O16B	100.17 (11)	Mo5^ii—O15C—Mo4^ii	97.60 (9)
O22T—Mo5—O16B	93.06 (11)	Mo4—O16B—Mo5	117.72 (11)
O18B—Mo5—O16B	150.02 (10)	Mo4—O17B—Mo6^ii	118.91 (12)
O21T—Mo5—O15C^ii	93.02 (11)	Mo5—O18B—Mo6	119.24 (12)
O22T—Mo5—O15C^ii	156.22 (11)	H25A—O25W—H25B	96 (5)
O18B—Mo5—O15C^ii	86.51 (10)	H26A—O26W—H26B	107 (5)
O16B—Mo5—O15C^ii	69.93 (9)	H27A—O27W—H27B	108 (5)
O21T—Mo5—O13C	161.33 (11)	H28A—O28W—H28B	104 (5)
O22T—Mo5—O13C	91.69 (11)	H29A—O29W—H29B	121 (6)
O18B—Mo5—O13C	72.50 (10)	H30A—O30W—H30B	83 (7)
O16B—Mo5—O13C	81.93 (10)	H31A—O31W—H31B	107 (5)
O15C^ii—Mo5—O13C	70.11 (9)	H32A—O32W—H32B	112 (5)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1C—H1···O22T^x	0.70 (6)	2.11 (6)	2.789 (4)	164 (6)
O2C—H2···O27W	0.76 (6)	2.01 (6)	2.753 (4)	166 (6)
O3C—H3···O31W^xi	0.82 (6)	1.79 (6)	2.604 (4)	176 (6)
O5B—H5···O16B^iii	1.23 (1)	1.23 (1)	2.461 (3)	175 (5)
O13C—H13···O12T^iii	0.70 (5)	2.05 (5)	2.734 (4)	167 (5)
O14C—H14···O32W	0.81 (5)	2.01 (5)	2.776 (4)	158 (5)
O15C—H15···O28W^ii	0.76 (6)	1.87 (6)	2.619 (4)	170 (6)
O25W—H25A···O21T	0.92 (3)	1.96 (3)	2.838 (4)	157 (5)
O25W—H25B···O20T	0.93 (3)	1.92 (3)	2.819 (4)	162 (5)
O26W—H26A···O4B^i	0.91 (3)	1.89 (3)	2.748 (4)	158 (5)
O26W—H26B···O24T^iii	0.91 (3)	1.91 (3)	2.798 (4)	164 (5)
O27W—H27A···O18B	0.90 (3)	1.95 (4)	2.775 (4)	151 (5)
O27W—H27B···O32W	0.91 (3)	1.92 (3)	2.825 (5)	171 (5)
O28W—H28A···O12T^xii	0.91 (3)	2.00 (4)	2.785 (4)	144 (5)
O28W—H28B···O31W^ii	0.90 (3)	1.82 (3)	2.706 (4)	170 (5)
O29W—H29A···O11T^i	0.95 (3)	2.11 (4)	2.949 (5)	146 (6)
O29W—H29B···O8T^vii	0.96 (3)	2.18 (3)	3.126 (5)	169 (6)
O31W—H31A···O26W^ii	0.90 (3)	1.77 (3)	2.665 (4)	170 (5)
O31W—H31B···O27W^ii	0.92 (3)	2.18 (4)	2.952 (4)	141 (4)
O32W—H32A···O30W	0.89 (3)	2.06 (3)	2.947 (6)	171 (5)
O32W—H32B···O6B^i	0.89 (3)	2.39 (5)	3.000 (4)	126 (5)

Symmetry codes: (i) −x+1, −y, −z+2; (ii) −x+1, −y+1, −z+1; (iii) −x+1, −y, −z+1; (vii) −x+1, −y+1, −z+2; (x) x, y, z+1; (xi) x, y−1, z+1; (xii) x, y+1, z.