The alluaudite-type crystal structures of Na2(Fe/Co)2Co(VO4)3 and Ag2(Fe/Co)2Co(VO4)3.

Single crystals of the title compounds, disodium di(cobalt/iron) cobalt tris-(orthovanadate), Na2(Fe/Co)2Co(VO4)3, and disilver di(cobalt/iron) cobalt tris-(orthovanadate), Ag2(Fe/Co)2Co(VO4)3, were grown from a melt consisting of stoichiometric mixtures of three metallic cation precursors and vanadium pentoxide. The difficulty to distinguish between cobalt and iron by using X-ray diffraction alone forced us to explore several models, assuming an oxidation state of +II for Co and +III for Fe and a partial cationic disorder in the Wyckoff site 8f containing a mixture of Co and Fe with a statistical distribution for the Na compound and an occupancy ratio of 0.4875:0.5125 (Co:Fe) for the Ag compound. The alluaudite-type structure is made up from [10-1] chains of [(Co,Fe)2O10] double octa-hedra linked by highly distorted [CoO6] octa-hedra via a common edge. The chains are linked through VO4 tetra-hedra, forming polyhedral sheets perpendicular to [010]. The stacking of the sheets defines two types of channels parallel to [001] where the Na(+) cations (both with full occupancy) or Ag(+) cations (one with occupancy 0.97) are located.

Chemical context

The needs of the society on the ‘energy front’ is one of the greatest challenges for present and future times. Materials with three-dimensional framework structures delimiting channels, as built of transition metal cations and polyanions (XO4), have become a subject of very intensive research worldwide since the discovery of the electrochemical activity of LiFePO4 (Padhi et al., 1997a ▸,b ▸). Hence, new transition metal-based materials adopting open three-dimensional framework structures have been synthesized and investigated by us over the last years. Thereby our attention has focused on the synthesis and characterization of new materials belonging to the family of alluaudites that, according to Moore (1971 ▸), has the general formula A(1)A(2)M(1)M(2)2(XO4)3. The A sites may be occupied by larger mono- and/or divalent cations, while the M sites correspond to bi- or trivalent transition metal cations in an octa­hedral environment. Alluaudite-like compounds, having open-framework structures, allow a certain prediction of physical properties and promising practical applications in several fields. For instance, alluaudite-like compounds exhibit electronic and/or ionic conductivity, as has been shown by Warner et al. (1993 ▸, 1994 ▸), which make them worthy of investigating their electrochemical performance. Mainly, several alluaudite-like phosphates have been tested as anode and/or cathode materials in Li-ion and/or Na-ion batteries. For example, Li0.78Na0.22MnPO4 was proposed by Kim et al. (2014 ▸) as a promising new positive electrode for Li-ion batteries. The sulfates Na2.44Mn1.79(SO4)3 (Dwibedi et al., 2015 ▸) and Na2+2Fe2−(SO4)3 (Dwibedi et al., 2016 ▸) were tested as electroactive materials for Na-ion batteries. In this context, we have investigated pseudo-ternary A 2O/MO/P2O5, pseudo-quaternary A 2O/MO/Fe2O3/P2O5, and more recently, A 2O/MO/Fe2O3/V2O5 systems synthesized via hydro­thermal or solid-state routes, resulting in new alluaudite-like phosphates AgMg3(HPO4)2PO4 (Assani et al., 2011 ▸), NaMg3(HPO4)2PO4 (Ould Saleck et al., 2015 ▸), Na2Co2Fe(PO4)3 (Bouraima et al., 2015 ▸), Na1.67Zn1.67Fe1.33(PO4)3 (Khmiyas et al., 2015 ▸), and most lately, the first alluaudite-like vanadate (Na0.70)(Na0.70Mn0.30)(Fe3+/Fe2+)2Fe2+(VO4)3 (Benhsina et al., 2016 ▸). As a continuation of our studies of phases with alluaudite-like structures, the present work reports details of the synthesis and crystal structures of the compounds M 2(Fe/Co)2Co(VO4)3 (M = Na, Ag).

Structural commentary

The two alluaudite-like vanadates, Na2(Fe/Co)2Co(VO4)3 and Ag2(Fe/Co)2Co(VO4)3, are isotypic. In the structure of Na2(Fe/Co)2Co(VO4)3 all sites are fully occupied and only the cationic site on Wyckoff position 8f shows disorder with a statistical distribution of Co and Fe, assuming oxidation state +II for Co and +III for Fe. In the structure of Ag2(Fe/Co)2Co(VO4)3 a small deficit in the Ag2 site was considered (occupancy 0.97) that is compensated by a slight excess of Fe (occupancy 0.51) compared with Co (occupancy 0.49) in the 8f mixed site, again under the assumption of oxidation state +II for Co and +III for Fe. The (Fe1,Co1) and Co2 sites have octa­hedral environments while the vanadium atoms are located in tetra­hedral environments. The sequence of different polyhedra forming the principal building units are shown in Figs. 1 ▸ and 2 ▸. The mixed-occupied sites containing the (Fe1,Co1) atoms form [(Co,Fe)2O10] dimers through edge-sharing of a single octa­hedron and are linked by highly distorted [CoO6] octa­hedra. The linkage of alternating [CoO6] octa­hedra and [(Co,Fe)2O10] double octa­hedra leads to the formation of infinite chains along the [10] direction (Fig. 3 ▸). The connection of these chains through VO4 tetra­hedra makes up sheets perpendicular to [010], as shown in Fig. 4 ▸. The stacking of these sheets defines an open three-dimensional framework delimiting two types of channels parallel to [001] where the M + cations (M = Na, Ag) are situated (Fig. 5 ▸). In the sodium compound, the Na1 site is coordinated by eight oxygen atoms with Na1—O distances in the range between 2.4118 (14) and 2.8820 (15) Å, while Na2 is surrounded by six oxygen atoms in a range between 2.4347 (14) and 2.780 (2) Å. In the silver compound, the Ag1 site is coordinated by six oxygen atoms in a range between 2.4244 (12) and 2.5960 (13) Å, whereas the Ag2 site is surrounded by four oxygen atoms in a range between 2.4708 (14) and 2.4779 (14) Å.

Figure 1

The principal building units in the structure of Na2(Fe/Co)2Co(VO4)3. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (i) x, −y + 1, z + ; (ii) −x + , −y + , −z + 2; (iii) x, y, z + 1; (iv) −x + , −y + , −z + 1; (v) −x + 1, y, −z + ; (vi) x, y, z − 1; (vii) −x + 1, y, −z + ; (viii) x − , −y + , z − ; (ix) −x + 1, −y + 1, −z + 1; (x) x, −y + 1, z − ; (xi) −x + 2, y, −z + ; (xii) −x + 2, −y + 1, −z + 1.]

Figure 2

The principal building units in the structure of Ag2(Fe/Co)2Co(VO4)3. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (i) x, −y + 1, z + ; (ii) −x + , −y + , −z + 2; (iii) x, y, z + 1; (iv) −x + , −y + , −z + 1; (v) −x + 1, y, −z + ; (vi) x, y, z − 1; (vii) −x + 1, y, −z + ; (viii) x − , −y + , z − ; (ix) −x + 1, −y + 1, −z + 1; (x) x, −y + 1, z − ; (xi) −x + 2, y, −z + ; (xii) −x + 2, −y + 1, −z + 1.]

Figure 3

Edge-sharing octa­hedra forming an infinite zigzag chain running along [10]. Data from Na2(Fe/Co)2Co(VO4)3.

Figure 4

A sheet perpendicular to [010], resulting from the connection of individual chains via VO4 tetra­hedra. Data from Na2(Fe/Co)2Co(VO4)3.

Figure 5

Polyhedral representation of Na2(Fe/Co)2Co(VO4)3 showing sodium cations in the channels extending along [001].

Synthesis and crystallization

The target compounds were obtained by solid-state reactions. A starting mixture of metallic iron (+ a few drops of HNO3), Co(CH3COO)2·4H2O, NH4VO3 and NaNO3 or AgNO3 was mixed in molar ratios M: Co: Fe: V = 2: 2: 1: 3 (M = Na or Ag). The mixture was placed in a platinum crucible and then heated gradually until melting (1253 K). Single crystals were obtained by cooling the molten product to room temperature at rate of 5 Kh−1. The resulting mixtures contained pink crystals (for M = Na) or green crystals (for M = Ag) of a suitable size for the X-ray diffraction study. The powder X-ray diffraction patterns are in good agreement with the simulated patterns, generated from the final structure models of the two compounds (see supplementary material).

Refinement

Crystal data, data collection and structure refinement details for both structures are summarized in Table 1 ▸.

Table 1

Experimental details

	(I)	(II)
Crystal data
Chemical formula	Na2(Co0.5Fe0.5)2Co(VO4)3	Ag1.97(Co0.49Fe0.51)2Co(VO4)3
M r	564.51	730.96
Crystal system, space group	Monoclinic, C2/c	Monoclinic, C2/c
Temperature (K)	296	296
a, b, c (Å)	11.7258 (2), 12.7819 (2), 6.8264 (1)	11.7846 (4), 12.8314 (4), 6.8064 (2)
β (°)	111.069 (1)	111.001 (1)
V (Å3)	954.73 (3)	960.85 (5)
Z	4	4
Radiation type	Mo Kα	Mo Kα
μ (mm−1)	7.85	11.60
Crystal size (mm)	0.32 × 0.25 × 0.19	0.34 × 0.22 × 0.17
Data collection
Diffractometer	Bruker X8 APEX	Bruker X8 APEX
Absorption correction	Multi-scan (SADABS; Bruker, 2009 ▸)	Multi-scan (SADABS; Bruker, 2009 ▸)
T min, T max	0.572, 0.747	0.439, 0.747
No. of measured, independent and observed [I > 2σ(I)] reflections	17675, 2094, 1893	15366, 2113, 1987
R int	0.047	0.039
(sin θ/λ)max (Å−1)	0.806	0.806
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.022, 0.054, 1.10	0.018, 0.041, 1.14
No. of reflections	2094	2113
No. of parameters	95	104
Δρmax, Δρmin (e Å−3)	0.88, −1.00	0.80, −1.66

Computer programs: APEX2 and SAINT (Bruker, 2009 ▸), SHELXT2014 (Sheldrick, 2015a ▸), SHELXL2014 (Sheldrick, 2015b ▸), ORTEP-3 for Windows (Farrugia, 2012 ▸), DIAMOND (Brandenburg, 2006 ▸) and publCIF (Westrip, 2010 ▸).

As a matter of fact, the distinction between cobalt and iron by X-ray diffraction is nearly impossible. Therefore we have examined several crystallographic models during crystal structure refinements of the title compounds. Based on the stoichiometric ratio of 1:2 for iron and cobalt in the starting materials, we assumed the same ratio in the crystal structures with oxidation states of +II for cobalt and and +III for iron. In the final model, Fe1 and Co1 atoms are constrained to share the same general position 8f of the space group C2/c. Electrical neutrality and bond valence sum calculations of all atoms (Brown & Altermatt, 1985 ▸) in the structures are in reasonable agreement with the final models. Bond valence sums (in valence units) for Na2(Fe/Co)2Co(VO4)3 are 1.07 for Na1, 0.86 for Na2, 2.24 for Co1, 1.97 for Co2, 2.69 for Fe1, 5.01 for V1, and 4.99 for V2. Values of the bond valence sums calculated for all oxygen atoms are between 1.90 and 2.07. Bond valence sums for Ag2(Fe/Co)2Co(VO4)3 are 1.01 for Ag1, O.72 for Ag2, 2.27 for Co1, 1.98 for Co2, 2.72 for Fe1, 4.99 for V1, and 4.94 for V2. The values of the O atoms are in the range 1.94 to 2.03. A very similar cationic distribution was observed by Yakubovich et al. (1977 ▸) in the alluaudite-type phosphate Na2(Fe3+/Fe2+)2Fe2+(PO4)3.

Refinement of Na2(Fe/Co)2Co(VO4)3: Co1 and Fe1 were constrained to share the same site in a statistical occupation with common displacement parameters. Reflection (132) probably was affected by the beam-stop and was omitted from the refinement. The remaining electron densities (max/min) in the final Fourier map were 0.46 Å and 0.71 Å away from atoms Na1 and Na2, respectively.

Refinement of Ag2(Fe/Co)2Co(VO4)3: The coordinates and displacement factors of Co1 and Fe1 atoms were refined independent from each other. An underoccupation of the Ag2 site was modelled with an occupancy of 0.97 which made it necessary to constrain the occupancies of the Co1 site (0.4875) and Fe1 site (0.5125) for electroneutrality. The remaining electron densities (max/min) in the final Fourier map were 0.61 Å and 0.66 Å away from Ag2.

Crystal structure: contains datablock(s) I, II, global. DOI: 10.1107/S2056989016009981/wm5292sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989016009981/wm5292Isup2.hkl

Structure factors: contains datablock(s) II. DOI: 10.1107/S2056989016009981/wm5292IIsup3.hkl

CCDC references: 1486597, 1486596

Additional supporting information: crystallographic information; 3D view; checkCIF report

Na2(Co·Fe)2Co(VO4)3	F(000) = 1068
Mr = 564.51	Dx = 3.927 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 11.7258 (2) Å	Cell parameters from 2094 reflections
b = 12.7819 (2) Å	θ = 2.5–35.0°
c = 6.8264 (1) Å	µ = 7.85 mm−1
β = 111.069 (1)°	T = 296 K
V = 954.73 (3) Å3	Block, pink
Z = 4	0.32 × 0.25 × 0.19 mm

Bruker X8 APEX diffractometer	2094 independent reflections
Radiation source: fine-focus sealed tube	1893 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.047
φ and ω scans	θmax = 35.0°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −17→18
Tmin = 0.572, Tmax = 0.747	k = −20→20
17675 measured reflections	l = −10→10

Refinement on F2	95 parameters
Least-squares matrix: full	0 restraints
R[F2 > 2σ(F2)] = 0.022	w = 1/[σ2(Fo2) + (0.0186P)2 + 2.754P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.054	(Δ/σ)max = 0.001
S = 1.10	Δρmax = 0.88 e Å−3
2094 reflections	Δρmin = −1.00 e Å−3

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.

	x	y	z	Uiso*/Ueq	Occ. (<1)
Fe1	0.79142 (2)	0.66131 (2)	0.88043 (4)	0.00595 (6)	0.5
Co1	0.79142 (2)	0.66131 (2)	0.88043 (4)	0.00595 (6)	0.5
Co2	0.5000	0.73184 (3)	0.2500	0.00727 (7)
V1	0.77138 (3)	0.61298 (2)	0.38340 (4)	0.00555 (6)
V2	0.5000	0.70722 (3)	0.7500	0.00629 (8)
Na1	0.5000	0.5000	0.5000	0.0123 (2)
Na2	1.0000	0.50245 (14)	0.7500	0.0257 (3)
O1	0.84286 (13)	0.67273 (11)	0.6264 (2)	0.0102 (2)
O2	0.62045 (12)	0.60248 (11)	0.3329 (2)	0.0116 (2)
O3	0.78619 (13)	0.68309 (11)	0.1758 (2)	0.0113 (2)
O6	0.61413 (13)	0.62261 (11)	0.7671 (2)	0.0120 (2)
O5	0.53637 (12)	0.77735 (11)	0.9853 (2)	0.0104 (2)
O4	0.84074 (13)	0.49296 (11)	0.4032 (2)	0.0108 (2)

	U11	U22	U33	U12	U13	U23
Fe1	0.00562 (10)	0.00715 (11)	0.00541 (10)	−0.00056 (7)	0.00237 (7)	−0.00051 (7)
Co1	0.00562 (10)	0.00715 (11)	0.00541 (10)	−0.00056 (7)	0.00237 (7)	−0.00051 (7)
Co2	0.00669 (14)	0.00821 (15)	0.00752 (13)	0.000	0.00330 (11)	0.000
V1	0.00559 (12)	0.00635 (12)	0.00449 (11)	−0.00001 (9)	0.00155 (9)	−0.00011 (8)
V2	0.00700 (17)	0.00647 (17)	0.00459 (15)	0.000	0.00113 (12)	0.000
Na1	0.0208 (6)	0.0070 (5)	0.0074 (4)	−0.0057 (4)	0.0030 (4)	−0.0015 (3)
Na2	0.0097 (5)	0.0565 (10)	0.0105 (5)	0.000	0.0031 (4)	0.000
O1	0.0115 (6)	0.0116 (6)	0.0074 (5)	−0.0037 (5)	0.0031 (4)	−0.0016 (4)
O2	0.0077 (5)	0.0107 (6)	0.0158 (6)	−0.0008 (4)	0.0035 (5)	0.0004 (5)
O3	0.0138 (6)	0.0126 (6)	0.0080 (5)	−0.0004 (5)	0.0043 (4)	0.0006 (4)
O6	0.0092 (6)	0.0098 (6)	0.0148 (6)	0.0012 (4)	0.0015 (5)	−0.0019 (5)
O5	0.0075 (5)	0.0156 (6)	0.0082 (5)	−0.0017 (5)	0.0028 (4)	−0.0025 (4)
O4	0.0102 (6)	0.0092 (6)	0.0129 (6)	0.0002 (4)	0.0042 (5)	−0.0015 (4)

Fe1—O6	2.0021 (14)	V2—O6v	1.6917 (14)
Fe1—O1	2.0359 (14)	V2—O5	1.7531 (13)
Fe1—O4i	2.0451 (14)	V2—O5v	1.7531 (13)
Fe1—O5ii	2.0497 (14)	Na1—O6	2.4118 (14)
Fe1—O3iii	2.0581 (14)	Na1—O6ix	2.4119 (14)
Fe1—O3iv	2.1633 (14)	Na1—O2ix	2.4841 (14)
Co2—O5v	2.0831 (14)	Na1—O2	2.4841 (14)
Co2—O5vi	2.0831 (14)	Na1—O2i	2.5626 (14)
Co2—O2	2.1153 (14)	Na1—O2vii	2.5626 (14)
Co2—O2vii	2.1153 (14)	Na1—O6x	2.8820 (15)
Co2—O1iv	2.1159 (13)	Na1—O6v	2.8820 (15)
Co2—O1viii	2.1159 (13)	Na2—O4xi	2.4347 (14)
V1—O2	1.6823 (14)	Na2—O4	2.4347 (14)
V1—O4	1.7188 (14)	Na2—O4i	2.4472 (15)
V1—O3	1.7374 (14)	Na2—O4xii	2.4472 (15)
V1—O1	1.7428 (13)	Na2—O1	2.780 (2)
V2—O6	1.6917 (14)	Na2—O1xi	2.780 (2)
O6—Fe1—O1	105.84 (6)	O6—Na1—O2ix	104.36 (5)
O6—Fe1—O4i	90.98 (6)	O6ix—Na1—O2ix	75.63 (5)
O1—Fe1—O4i	88.38 (6)	O6—Na1—O2	75.64 (5)
O6—Fe1—O5ii	170.54 (6)	O6ix—Na1—O2	104.37 (5)
O1—Fe1—O5ii	78.91 (5)	O2ix—Na1—O2	180.0
O4i—Fe1—O5ii	97.39 (6)	O6—Na1—O2i	71.50 (5)
O6—Fe1—O3iii	91.12 (6)	O6ix—Na1—O2i	108.50 (5)
O1—Fe1—O3iii	161.29 (6)	O2ix—Na1—O2i	63.02 (6)
O4i—Fe1—O3iii	99.39 (6)	O2—Na1—O2i	116.98 (6)
O5ii—Fe1—O3iii	83.21 (5)	O6—Na1—O2vii	108.50 (5)
O6—Fe1—O3iv	81.17 (6)	O6ix—Na1—O2vii	71.50 (5)
O1—Fe1—O3iv	91.00 (5)	O2ix—Na1—O2vii	116.98 (6)
O4i—Fe1—O3iv	171.64 (6)	O2—Na1—O2vii	63.02 (6)
O5ii—Fe1—O3iv	90.67 (6)	O2i—Na1—O2vii	180.0
O3iii—Fe1—O3iv	83.72 (5)	O6—Na1—O6x	121.93 (6)
O5v—Co2—O5vi	147.57 (8)	O6ix—Na1—O6x	58.07 (6)
O5v—Co2—O2	108.15 (5)	O2ix—Na1—O6x	114.84 (4)
O5vi—Co2—O2	97.18 (6)	O2—Na1—O6x	65.16 (4)
O5v—Co2—O2vii	97.18 (6)	O2i—Na1—O6x	89.66 (4)
O5vi—Co2—O2vii	108.15 (5)	O2vii—Na1—O6x	90.34 (4)
O2—Co2—O2vii	77.17 (8)	O6—Na1—O6v	58.07 (6)
O5v—Co2—O1iv	85.04 (5)	O6ix—Na1—O6v	121.93 (6)
O5vi—Co2—O1iv	76.38 (5)	O2ix—Na1—O6v	65.16 (4)
O2—Co2—O1iv	86.67 (5)	O2—Na1—O6v	114.84 (4)
O2vii—Co2—O1iv	163.59 (6)	O2i—Na1—O6v	90.34 (4)
O5v—Co2—O1viii	76.38 (5)	O2vii—Na1—O6v	89.66 (4)
O5vi—Co2—O1viii	85.04 (5)	O6x—Na1—O6v	180.0
O2—Co2—O1viii	163.59 (6)	O4xi—Na2—O4	174.29 (11)
O2vii—Co2—O1viii	86.67 (5)	O4xi—Na2—O4i	91.26 (5)
O1iv—Co2—O1viii	109.60 (8)	O4—Na2—O4i	88.87 (5)
O2—V1—O4	112.22 (7)	O4xi—Na2—O4xii	88.87 (5)
O2—V1—O3	106.27 (7)	O4—Na2—O4xii	91.26 (5)
O4—V1—O3	109.96 (7)	O4i—Na2—O4xii	177.25 (11)
O2—V1—O1	109.92 (7)	O4xi—Na2—O1	121.82 (7)
O4—V1—O1	105.32 (7)	O4—Na2—O1	63.31 (5)
O3—V1—O1	113.29 (7)	O4i—Na2—O1	65.58 (5)
O6—V2—O6v	100.53 (10)	O4xii—Na2—O1	112.08 (6)
O6—V2—O5	109.75 (7)	O4xi—Na2—O1xi	63.31 (5)
O6v—V2—O5	108.41 (7)	O4—Na2—O1xi	121.82 (7)
O6—V2—O5v	108.42 (7)	O4i—Na2—O1xi	112.08 (6)
O6v—V2—O5v	109.75 (7)	O4xii—Na2—O1xi	65.58 (5)
O5—V2—O5v	118.49 (10)	O1—Na2—O1xi	76.92 (7)
O6—Na1—O6ix	180.0

Ag1.97(Co0.49Fe0.51)2Co(VO4)3	F(000) = 1350
Mr = 730.96	Dx = 5.053 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 11.7846 (4) Å	Cell parameters from 2113 reflections
b = 12.8314 (4) Å	θ = 2.4–35.0°
c = 6.8064 (2) Å	µ = 11.60 mm−1
β = 111.001 (1)°	T = 296 K
V = 960.85 (5) Å3	Block, green
Z = 4	0.34 × 0.22 × 0.17 mm

Bruker X8 APEX diffractometer	2113 independent reflections
Radiation source: fine-focus sealed tube	1987 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.039
φ and ω scans	θmax = 35.0°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −18→18
Tmin = 0.439, Tmax = 0.747	k = −20→20
15366 measured reflections	l = −9→10

Refinement on F2	0 restraints
Least-squares matrix: full	w = 1/[σ2(Fo2) + (0.0093P)2 + 2.3975P] where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.018	(Δ/σ)max = 0.001
wR(F2) = 0.041	Δρmax = 0.80 e Å−3
S = 1.14	Δρmin = −1.66 e Å−3
2113 reflections	Extinction correction: SHELXL2014 (Sheldrick, 2015b), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
104 parameters	Extinction coefficient: 0.00190 (7)

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.

	x	y	z	Uiso*/Ueq	Occ. (<1)
Ag1	0.0000	0.5000	0.0000	0.02187 (6)
Ag2	0.5000	0.50840 (2)	0.7500	0.02578 (6)	0.97
Co1	0.2919 (4)	0.6616 (4)	0.3791 (8)	0.0066 (12)	0.4875
Fe1	0.2923 (4)	0.6620 (4)	0.3814 (8)	0.0061 (12)	0.5125
Co2	0.0000	0.73364 (2)	0.7500	0.00755 (6)
V1	0.27106 (2)	0.38672 (2)	0.38255 (4)	0.00573 (5)
V2	0.0000	0.70581 (3)	0.2500	0.00609 (6)
O1	0.34160 (11)	0.32595 (9)	0.62391 (19)	0.0103 (2)
O2	0.28472 (11)	0.31626 (10)	0.17435 (19)	0.0109 (2)
O3	0.12124 (11)	0.39463 (10)	0.3352 (2)	0.0121 (2)
O4	0.33731 (12)	0.50845 (9)	0.3988 (2)	0.0123 (2)
O5	0.03699 (11)	0.77654 (10)	0.48520 (19)	0.0100 (2)
O6	0.11558 (11)	0.62338 (9)	0.2663 (2)	0.0114 (2)

	U11	U22	U33	U12	U13	U23
Ag1	0.03724 (13)	0.01563 (9)	0.01248 (9)	−0.01172 (8)	0.00860 (8)	−0.00330 (6)
Ag2	0.01181 (9)	0.04845 (15)	0.01618 (10)	0.000	0.00390 (8)	0.000
Co1	0.0072 (18)	0.0061 (17)	0.0085 (18)	0.0017 (12)	0.0052 (12)	−0.0004 (12)
Fe1	0.0059 (17)	0.0082 (18)	0.0032 (15)	−0.0027 (12)	0.0007 (11)	−0.0007 (11)
Co2	0.00710 (12)	0.00870 (12)	0.00779 (13)	0.000	0.00380 (10)	0.000
V1	0.00651 (10)	0.00586 (10)	0.00488 (10)	0.00018 (7)	0.00212 (8)	0.00004 (7)
V2	0.00679 (14)	0.00648 (13)	0.00465 (14)	0.000	0.00161 (11)	0.000
O1	0.0119 (5)	0.0111 (5)	0.0081 (5)	0.0027 (4)	0.0038 (4)	0.0013 (4)
O2	0.0129 (5)	0.0121 (5)	0.0083 (5)	−0.0007 (4)	0.0045 (4)	−0.0007 (4)
O3	0.0094 (5)	0.0113 (5)	0.0156 (6)	0.0007 (4)	0.0045 (4)	−0.0005 (4)
O4	0.0132 (5)	0.0087 (5)	0.0156 (6)	−0.0002 (4)	0.0060 (5)	0.0010 (4)
O5	0.0091 (5)	0.0136 (5)	0.0078 (5)	−0.0018 (4)	0.0036 (4)	−0.0019 (4)
O6	0.0088 (5)	0.0103 (5)	0.0137 (5)	0.0000 (4)	0.0024 (4)	−0.0021 (4)

Ag1—O6i	2.4244 (12)	Fe1—O1ii	2.040 (6)
Ag1—O6	2.4244 (12)	Fe1—O5vii	2.045 (5)
Ag1—O3ii	2.5051 (13)	Fe1—O2v	2.047 (5)
Ag1—O3iii	2.5051 (13)	Fe1—O2viii	2.154 (5)
Ag1—O3	2.5960 (13)	Co2—O5ix	2.0747 (12)
Ag1—O3i	2.5960 (13)	Co2—O5	2.0748 (12)
Ag2—O4	2.4708 (14)	Co2—O1x	2.1156 (12)
Ag2—O4iv	2.4709 (14)	Co2—O1xi	2.1156 (12)
Ag2—O4v	2.4779 (14)	Co2—O3xii	2.1197 (13)
Ag2—O4vi	2.4779 (14)	Co2—O3v	2.1197 (13)
Co1—O6	2.001 (5)	V1—O3	1.6804 (13)
Co1—O1ii	2.028 (6)	V1—O4	1.7319 (12)
Co1—O4	2.028 (5)	V1—O2	1.7363 (12)
Co1—O5vii	2.053 (5)	V1—O1	1.7375 (12)
Co1—O2v	2.061 (5)	V2—O6	1.6965 (12)
Co1—O2viii	2.157 (5)	V2—O6iii	1.6965 (12)
Fe1—O6	2.007 (5)	V2—O5iii	1.7539 (12)
Fe1—O4	2.033 (5)	V2—O5	1.7539 (12)
O6i—Ag1—O6	180.0	O6—Fe1—O5vii	170.5 (3)
O6i—Ag1—O3ii	105.99 (4)	O4—Fe1—O5vii	98.8 (2)
O6—Ag1—O3ii	74.01 (4)	O1ii—Fe1—O5vii	79.3 (2)
O6i—Ag1—O3iii	74.01 (4)	O6—Fe1—O2v	90.7 (2)
O6—Ag1—O3iii	105.99 (4)	O4—Fe1—O2v	100.2 (2)
O3ii—Ag1—O3iii	180.0	O1ii—Fe1—O2v	162.1 (3)
O6i—Ag1—O3	107.57 (4)	O5vii—Fe1—O2v	83.95 (17)
O6—Ag1—O3	72.43 (4)	O6—Fe1—O2viii	81.09 (17)
O3ii—Ag1—O3	116.87 (5)	O4—Fe1—O2viii	170.3 (2)
O3iii—Ag1—O3	63.13 (5)	O1ii—Fe1—O2viii	90.6 (2)
O6i—Ag1—O3i	72.43 (4)	O5vii—Fe1—O2viii	90.5 (2)
O6—Ag1—O3i	107.57 (4)	O2v—Fe1—O2viii	83.31 (18)
O3ii—Ag1—O3i	63.13 (5)	O5ix—Co2—O5	149.23 (7)
O3iii—Ag1—O3i	116.87 (5)	O5ix—Co2—O1x	85.91 (5)
O3—Ag1—O3i	180.0	O5—Co2—O1x	76.96 (5)
O4—Ag2—O4iv	179.97 (6)	O5ix—Co2—O1xi	76.96 (5)
O4—Ag2—O4v	87.12 (4)	O5—Co2—O1xi	85.91 (5)
O4iv—Ag2—O4v	92.89 (4)	O1x—Co2—O1xi	111.91 (7)
O4—Ag2—O4vi	92.89 (4)	O5ix—Co2—O3xii	96.48 (5)
O4iv—Ag2—O4vi	87.12 (4)	O5—Co2—O3xii	107.40 (5)
O4v—Ag2—O4vi	169.99 (6)	O1x—Co2—O3xii	162.94 (5)
O6—Co1—O1ii	105.6 (2)	O1xi—Co2—O3xii	85.03 (5)
O6—Co1—O4	90.1 (2)	O5ix—Co2—O3v	107.40 (5)
O1ii—Co1—O4	89.02 (19)	O5—Co2—O3v	96.48 (5)
O6—Co1—O5vii	170.0 (3)	O1x—Co2—O3v	85.03 (5)
O1ii—Co1—O5vii	79.4 (2)	O1xi—Co2—O3v	162.94 (5)
O4—Co1—O5vii	98.73 (19)	O3xii—Co2—O3v	78.12 (7)
O6—Co1—O2v	90.4 (2)	O3—V1—O4	112.11 (6)
O1ii—Co1—O2v	161.7 (3)	O3—V1—O2	105.86 (6)
O4—Co1—O2v	99.9 (2)	O4—V1—O2	110.50 (6)
O5vii—Co1—O2v	83.40 (18)	O3—V1—O1	108.79 (6)
O6—Co1—O2viii	81.15 (16)	O4—V1—O1	107.01 (6)
O1ii—Co1—O2viii	90.9 (2)	O2—V1—O1	112.65 (6)
O4—Co1—O2viii	170.8 (3)	O6—V2—O6iii	102.86 (8)
O5vii—Co1—O2viii	90.3 (2)	O6—V2—O5iii	108.27 (6)
O2v—Co1—O2viii	82.90 (17)	O6iii—V2—O5iii	109.38 (6)
O6—Fe1—O4	89.8 (2)	O6—V2—O5	109.37 (6)
O6—Fe1—O1ii	105.0 (2)	O6iii—V2—O5	108.27 (6)
O4—Fe1—O1ii	88.6 (2)	O5iii—V2—O5	117.68 (8)