The influence of P/As substitution in the melilite-like Na₂Co(P_2–xAs_x)O₇ (x = 0.40 and 0.93) solid solutions

To investigate the influence of P/As substitution on structures and electrical properties, e.g. the effect on material densities, two new solid P/As-doped solutions, Na₂CoP_1.60As_0.40O₇ (disodium cobalt di­phospho­rus arsenic hepta­oxide) and Na₂CoP_1.07As_0.93O₇ (disodium cobalt phospho­rus arsenic hepta­oxide), with melilite-like structures have been synthesized by solid-state reactions. Their unit-cell parameters are in agreement with Vegard's law. The obtained structural models were investigated by the bond valence sum (BVS) and charge distribution (CHARDI) validation tools and, for the latter, the structures are described as being built on anion-centred polyhedra. The frameworks can be described as layered and formed by {[Co(P,As)₂O₇]²⁻}_∞ slabs, with alkali cations sandwiched between the layers and with the inter­layer spaces increased due to P/As substitution. The BVS model was extended to a preliminary simulation of the sodium conduction properties in the studied structural type and suggests that the most probable sodium conduction pathways are bidimensional, at the (002) planes.

Computing details

For both compounds, data collection: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992); cell refinement: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: DIAMOND (Brandenburg, 2008); software used to prepare material for publication: WinGX (Farrugia, 2012) and publCIF (Westrip, 2010).

(I) Disodium cobalt diphosphorus arsenic heptaoxide

Crystal data

Na2CoP1.60As0.40O7	Dx = 3.184 Mg m^−3
Mr = 296.43	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P42/mnm	Cell parameters from 25 reflections
a = 7.737 (2) Å	θ = 12.5–14.9°
c = 10.331 (4) Å	µ = 5.44 mm^−1
V = 618.3 (4) Å^3	T = 293 K
Z = 4	Parallelepiped, blue
F(000) = 569	0.24 × 0.24 × 0.10 mm

Data collection

Enraf–Nonius CAD-4 diffractometer	318 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.057
Graphite monochromator	θmax = 27.0°, θmin = 3.3°
w/2θ scans	h = −9→1
Absorption correction: ψ scan (North et al., 1968)	k = −9→1
Tmin = 0.642, Tmax = 0.999	l = −13→1
1008 measured reflections	2 standard reflections every 120 min
394 independent reflections	intensity decay: 1.0%

Refinement

Refinement on F^2	1 restraint
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F^2 > 2σ(F^2)] = 0.040	Secondary atom site location: difference Fourier map
wR(F^2) = 0.112	w = 1/[σ^2(Fo^2) + (0.0586P)^2 + 0.4834P] where P = (Fo^2 + 2Fc^2)/3
S = 1.22	(Δ/σ)max < 0.001
394 reflections	Δρmax = 1.00 e Å^−3
48 parameters	Δρmin = −0.50 e Å^−3

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	Occ. (<1)
Co1	0.0000	0.5000	0.2500	0.0244 (5)
P1	0.36320 (11)	0.36320 (11)	0.28845 (11)	0.0194 (5)	0.797 (6)
As1	0.36320 (11)	0.36320 (11)	0.28845 (11)	0.0194 (5)	0.203 (6)
Na1	0.1986 (3)	0.1986 (3)	0.0000	0.0346 (10)
Na2	0.3592 (4)	0.6408 (4)	0.0000	0.0288 (9)
O1	0.3651 (4)	0.3651 (4)	0.1413 (5)	0.0317 (12)
O2	0.4653 (7)	0.5347 (7)	0.3444 (8)	0.024 (2)	0.5
O3A	0.213 (2)	0.458 (2)	0.3525 (16)	0.026 (2)	0.44 (2)
O3B	0.179 (2)	0.376 (3)	0.344 (2)	0.026 (2)	0.34 (3)
O3C	0.180 (5)	0.418 (6)	0.366 (4)	0.026 (2)	0.22 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Co1	0.0254 (5)	0.0254 (5)	0.0223 (8)	0.000	0.000	0.000
P1	0.0201 (5)	0.0201 (5)	0.0180 (7)	0.0008 (5)	0.0010 (4)	0.0010 (4)
As1	0.0201 (5)	0.0201 (5)	0.0180 (7)	0.0008 (5)	0.0010 (4)	0.0010 (4)
Na1	0.0372 (14)	0.0372 (14)	0.029 (2)	−0.0192 (18)	0.000	0.000
Na2	0.0300 (12)	0.0300 (12)	0.0264 (19)	0.0043 (17)	0.000	0.000
O1	0.0355 (17)	0.0355 (17)	0.024 (3)	−0.012 (2)	−0.0030 (14)	−0.0030 (14)
O2	0.027 (3)	0.027 (3)	0.017 (4)	0.002 (4)	0.004 (2)	−0.004 (2)
O3A	0.016 (4)	0.040 (7)	0.023 (4)	−0.002 (4)	0.002 (3)	0.000 (5)
O3B	0.016 (4)	0.040 (7)	0.023 (4)	−0.002 (4)	0.002 (3)	0.000 (5)
O3C	0.016 (4)	0.040 (7)	0.023 (4)	−0.002 (4)	0.002 (3)	0.000 (5)

Geometric parameters (Å, º)

Co1—O3B^i	1.94 (2)	Na1—O3C^ix	2.74 (5)
Co1—O3B^ii	1.94 (2)	Na1—O3C^vii	2.74 (5)
Co1—O3B^iii	1.94 (2)	Na1—O3C^viii	2.74 (5)
Co1—O3B	1.94 (2)	Na1—O3C^i	2.74 (5)
Co1—O3C	1.95 (3)	Na2—O3B^x	2.45 (2)
Co1—O3C^i	1.95 (3)	Na2—O3B^xi	2.45 (2)
Co1—O3C^ii	1.95 (3)	Na2—O3B^ii	2.45 (2)
Co1—O3C^iii	1.95 (3)	Na2—O3B^xii	2.45 (2)
Co1—O3A^i	1.985 (16)	Na2—O3C^xi	2.57 (4)
Co1—O3A^ii	1.985 (16)	Na2—O3C^x	2.57 (4)
Co1—O3A^iii	1.985 (16)	Na2—O3C^xii	2.57 (4)
Co1—O3A	1.985 (16)	Na2—O3C^ii	2.57 (4)
P1—O1	1.521 (5)	Na2—O1	2.585 (5)
P1—O3A^iv	1.526 (16)	Na2—O1^vi	2.585 (5)
P1—O3A	1.526 (16)	Na2—O1^v	2.585 (5)
P1—O3B^iv	1.538 (19)	Na2—O1^xiii	2.585 (5)
P1—O3B	1.538 (19)	O1—Na2^xiii	2.585 (5)
P1—O2^v	1.649 (3)	O2—O2^v	0.760 (14)
P1—O2	1.649 (3)	O2—As1^v	1.649 (3)
P1—O3C^iv	1.68 (4)	O2—P1^v	1.649 (3)
P1—O3C	1.68 (4)	O2—Na1^xiv	2.408 (8)
Na1—O1^vi	2.334 (5)	O2—Na1^xv	3.016 (8)
Na1—O1	2.334 (5)	O3A—O3B	0.69 (2)
Na1—O2^vii	2.408 (8)	O3A—Na1^xiv	2.499 (15)
Na1—O2^viii	2.408 (8)	O3A—Na2^xvi	2.944 (17)
Na1—O3A^ix	2.499 (15)	O3B—Na2^xvi	2.45 (2)
Na1—O3A^vii	2.499 (15)	O3C—Na2^xvi	2.57 (4)
Na1—O3A^i	2.499 (15)	O3C—Na1^xiv	2.74 (5)
Na1—O3A^viii	2.499 (15)
O3B^i—Co1—O3B^ii	120.2 (13)	O3A^ix—Na1—O3C^ix	7.7 (10)
O3B^i—Co1—O3B^iii	104.4 (6)	O3A^vii—Na1—O3C^ix	99.4 (10)
O3B^ii—Co1—O3B^iii	104.4 (6)	O3A^i—Na1—O3C^ix	68.0 (10)
O3B^i—Co1—O3B	104.4 (6)	O3A^viii—Na1—O3C^ix	141.2 (6)
O3B^ii—Co1—O3B	104.4 (6)	O1^vi—Na1—O3C^vii	86.1 (8)
O3B^iii—Co1—O3B	120.2 (13)	O1—Na1—O3C^vii	124.3 (9)
O3B^i—Co1—O3C	115.4 (16)	O2^vii—Na1—O3C^vii	55.0 (9)
O3B^ii—Co1—O3C	100.8 (14)	O2^viii—Na1—O3C^vii	95.8 (8)
O3B^iii—Co1—O3C	111.4 (15)	O3A^ix—Na1—O3C^vii	99.4 (10)
O3B—Co1—O3C	11.7 (12)	O3A^vii—Na1—O3C^vii	7.7 (10)
O3B^i—Co1—O3C^i	11.7 (12)	O3A^i—Na1—O3C^vii	141.2 (6)
O3B^ii—Co1—O3C^i	111.4 (15)	O3A^viii—Na1—O3C^vii	68.0 (10)
O3B^iii—Co1—O3C^i	115.3 (16)	O3C^ix—Na1—O3C^vii	106.7 (19)
O3B—Co1—O3C^i	100.8 (14)	O1^vi—Na1—O3C^viii	124.3 (9)
O3C—Co1—O3C^i	112.3 (14)	O1—Na1—O3C^viii	86.1 (8)
O3B^i—Co1—O3C^ii	111.4 (15)	O2^vii—Na1—O3C^viii	95.8 (8)
O3B^ii—Co1—O3C^ii	11.7 (12)	O2^viii—Na1—O3C^viii	55.0 (9)
O3B^iii—Co1—O3C^ii	100.8 (14)	O3A^ix—Na1—O3C^viii	141.2 (6)
O3B—Co1—O3C^ii	115.4 (16)	O3A^vii—Na1—O3C^viii	68.0 (10)
O3C—Co1—O3C^ii	112.3 (14)	O3A^i—Na1—O3C^viii	99.4 (10)
O3C^i—Co1—O3C^ii	104 (3)	O3A^viii—Na1—O3C^viii	7.7 (10)
O3B^i—Co1—O3C^iii	100.8 (14)	O3C^ix—Na1—O3C^viii	142.9 (15)
O3B^ii—Co1—O3C^iii	115.3 (16)	O3C^vii—Na1—O3C^viii	60.7 (18)
O3B^iii—Co1—O3C^iii	11.7 (12)	O1^vi—Na1—O3C^i	124.3 (9)
O3B—Co1—O3C^iii	111.4 (15)	O1—Na1—O3C^i	86.1 (8)
O3C—Co1—O3C^iii	104 (3)	O2^vii—Na1—O3C^i	95.8 (8)
O3C^i—Co1—O3C^iii	112.3 (14)	O2^viii—Na1—O3C^i	55.0 (9)
O3C^ii—Co1—O3C^iii	112.3 (14)	O3A^ix—Na1—O3C^i	68.0 (10)
O3B^i—Co1—O3A^i	20.3 (7)	O3A^vii—Na1—O3C^i	141.2 (6)
O3B^ii—Co1—O3A^i	113.9 (6)	O3A^i—Na1—O3C^i	7.7 (10)
O3B^iii—Co1—O3A^i	124.0 (7)	O3A^viii—Na1—O3C^i	99.4 (10)
O3B—Co1—O3A^i	88.4 (7)	O3C^ix—Na1—O3C^i	60.7 (18)
O3C—Co1—O3A^i	100.0 (13)	O3C^vii—Na1—O3C^i	142.9 (15)
O3C^i—Co1—O3A^i	12.4 (12)	O3C^viii—Na1—O3C^i	106.7 (19)
O3C^ii—Co1—O3A^i	108.6 (12)	O3B^x—Na2—O3B^xi	104.7 (9)
O3C^iii—Co1—O3A^i	118.9 (13)	O3B^x—Na2—O3B^ii	82.4 (10)
O3B^i—Co1—O3A^ii	113.9 (6)	O3B^xi—Na2—O3B^ii	52.2 (10)
O3B^ii—Co1—O3A^ii	20.3 (7)	O3B^x—Na2—O3B^xii	52.2 (10)
O3B^iii—Co1—O3A^ii	88.4 (7)	O3B^xi—Na2—O3B^xii	82.4 (10)
O3B—Co1—O3A^ii	124.0 (7)	O3B^ii—Na2—O3B^xii	104.7 (9)
O3C—Co1—O3A^ii	118.9 (13)	O3B^x—Na2—O3C^xi	99.5 (9)
O3C^i—Co1—O3A^ii	108.6 (12)	O3B^xi—Na2—O3C^xi	8.7 (9)
O3C^ii—Co1—O3A^ii	12.4 (12)	O3B^ii—Na2—O3C^xi	57.1 (10)
O3C^iii—Co1—O3A^ii	100.0 (13)	O3B^xii—Na2—O3C^xi	73.8 (14)
O3A^i—Co1—O3A^ii	115.5 (10)	O3B^x—Na2—O3C^x	8.7 (9)
O3B^i—Co1—O3A^iii	88.4 (7)	O3B^xi—Na2—O3C^x	99.5 (9)
O3B^ii—Co1—O3A^iii	124.0 (7)	O3B^ii—Na2—O3C^x	73.8 (14)
O3B^iii—Co1—O3A^iii	20.3 (7)	O3B^xii—Na2—O3C^x	57.1 (10)
O3B—Co1—O3A^iii	113.9 (6)	O3C^xi—Na2—O3C^x	95.3 (17)
O3C—Co1—O3A^iii	108.6 (12)	O3B^x—Na2—O3C^xii	57.1 (10)
O3C^i—Co1—O3A^iii	100.0 (13)	O3B^xi—Na2—O3C^xii	73.8 (14)
O3C^ii—Co1—O3A^iii	118.9 (13)	O3B^ii—Na2—O3C^xii	99.5 (9)
O3C^iii—Co1—O3A^iii	12.4 (12)	O3B^xii—Na2—O3C^xii	8.7 (9)
O3A^i—Co1—O3A^iii	106.5 (5)	O3C^xi—Na2—O3C^xii	65 (2)
O3A^ii—Co1—O3A^iii	106.5 (5)	O3C^x—Na2—O3C^xii	60.8 (18)
O3B^i—Co1—O3A	124.0 (7)	O3B^x—Na2—O3C^ii	73.8 (14)
O3B^ii—Co1—O3A	88.4 (7)	O3B^xi—Na2—O3C^ii	57.1 (10)
O3B^iii—Co1—O3A	113.9 (6)	O3B^ii—Na2—O3C^ii	8.7 (9)
O3B—Co1—O3A	20.3 (7)	O3B^xii—Na2—O3C^ii	99.5 (9)
O3C—Co1—O3A	12.4 (12)	O3C^xi—Na2—O3C^ii	60.8 (18)
O3C^i—Co1—O3A	118.9 (13)	O3C^x—Na2—O3C^ii	65 (2)
O3C^ii—Co1—O3A	100.0 (13)	O3C^xii—Na2—O3C^ii	95.3 (17)
O3C^iii—Co1—O3A	108.6 (12)	O3B^x—Na2—O1	119.0 (5)
O3A^i—Co1—O3A	106.5 (5)	O3B^xi—Na2—O1	104.1 (5)
O3A^ii—Co1—O3A	106.5 (5)	O3B^ii—Na2—O1	75.0 (4)
O3A^iii—Co1—O3A	115.5 (10)	O3B^xii—Na2—O1	170.7 (5)
O1—P1—O3A^iv	115.8 (6)	O3C^xi—Na2—O1	112.7 (11)
O1—P1—O3A	115.8 (6)	O3C^x—Na2—O1	114.6 (9)
O3A^iv—P1—O3A	123.1 (13)	O3C^xii—Na2—O1	174.0 (8)
O1—P1—O3B^iv	112.4 (8)	O3C^ii—Na2—O1	79.0 (8)
O3A^iv—P1—O3B^iv	26.2 (9)	O3B^x—Na2—O1^vi	75.0 (4)
O3A—P1—O3B^iv	109.5 (9)	O3B^xi—Na2—O1^vi	170.7 (5)
O1—P1—O3B	112.4 (8)	O3B^ii—Na2—O1^vi	119.0 (5)
O3A^iv—P1—O3B	109.5 (9)	O3B^xii—Na2—O1^vi	104.1 (5)
O3A—P1—O3B	26.2 (9)	O3C^xi—Na2—O1^vi	174.0 (8)
O3B^iv—P1—O3B	89.0 (15)	O3C^x—Na2—O1^vi	79.0 (8)
O1—P1—O2^v	109.8 (3)	O3C^xii—Na2—O1^vi	112.8 (11)
O3A^iv—P1—O2^v	79.9 (6)	O3C^ii—Na2—O1^vi	114.6 (9)
O3A—P1—O2^v	103.3 (6)	O1—Na2—O1^vi	68.7 (2)
O3B^iv—P1—O2^v	105.1 (8)	O3B^x—Na2—O1^v	170.7 (5)
O3B—P1—O2^v	125.7 (8)	O3B^xi—Na2—O1^v	75.0 (4)
O1—P1—O2	109.8 (3)	O3B^ii—Na2—O1^v	104.1 (5)
O3A^iv—P1—O2	103.3 (6)	O3B^xii—Na2—O1^v	119.0 (5)
O3A—P1—O2	79.9 (6)	O3C^xi—Na2—O1^v	79.0 (8)
O3B^iv—P1—O2	125.7 (8)	O3C^x—Na2—O1^v	174.0 (8)
O3B—P1—O2	105.1 (8)	O3C^xii—Na2—O1^v	114.6 (9)
O2^v—P1—O2	26.6 (5)	O3C^ii—Na2—O1^v	112.8 (11)
O1—P1—O3C^iv	118.9 (13)	O1—Na2—O1^v	69.64 (19)
O3A^iv—P1—O3C^iv	14.2 (14)	O1^vi—Na2—O1^v	106.83 (18)
O3A—P1—O3C^iv	113.0 (16)	O3B^x—Na2—O1^xiii	104.1 (5)
O3B^iv—P1—O3C^iv	13.2 (14)	O3B^xi—Na2—O1^xiii	119.0 (5)
O3B—P1—O3C^iv	96.3 (15)	O3B^ii—Na2—O1^xiii	170.7 (5)
O2^v—P1—O3C^iv	91.9 (17)	O3B^xii—Na2—O1^xiii	75.0 (4)
O2—P1—O3C^iv	112.9 (16)	O3C^xi—Na2—O1^xiii	114.6 (9)
O1—P1—O3C	118.9 (13)	O3C^x—Na2—O1^xiii	112.8 (11)
O3A^iv—P1—O3C	113.0 (16)	O3C^xii—Na2—O1^xiii	79.0 (8)
O3A—P1—O3C	14.2 (14)	O3C^ii—Na2—O1^xiii	174.0 (8)
O3B^iv—P1—O3C	96.3 (15)	O1—Na2—O1^xiii	106.83 (18)
O3B—P1—O3C	13.2 (14)	O1^vi—Na2—O1^xiii	69.64 (19)
O2^v—P1—O3C	112.9 (16)	O1^v—Na2—O1^xiii	68.7 (2)
O2—P1—O3C	91.9 (16)	P1—O1—Na1	127.9 (3)
O3C^iv—P1—O3C	101 (3)	P1—O1—Na2^xiii	124.91 (18)
O3A^iv—P1—Na1^xv	41.6 (6)	Na1—O1—Na2^xiii	95.32 (15)
O3A—P1—Na1^xv	111.6 (6)	P1—O1—Na2	124.91 (18)
O3B^iv—P1—Na1^xv	65.4 (8)	Na1—O1—Na2	95.32 (15)
O3B—P1—Na1^xv	118.2 (8)	Na2^xiii—O1—Na2	73.17 (18)
O2^v—P1—Na1^xv	40.0 (2)	O2^v—O2—As1^v	76.7 (2)
O2—P1—Na1^xv	61.7 (3)	O2^v—O2—P1^v	76.7 (2)
O3C^iv—P1—Na1^xv	52.2 (16)	As1^v—O2—P1^v	0.00 (9)
O3C—P1—Na1^xv	111.6 (13)	O2^v—O2—P1	76.7 (2)
Na2^xvi—P1—Na1^xv	84.19 (5)	As1^v—O2—P1	130.4 (5)
Na1^xiv—P1—Na1^xv	78.72 (10)	P1^v—O2—P1	130.4 (5)
O1^vi—Na1—O1	77.4 (3)	O2^v—O2—Na1^xiv	138.1 (2)
O1^vi—Na1—O2^vii	99.4 (2)	As1^v—O2—Na1^xiv	113.9 (2)
O1—Na1—O2^vii	176.8 (3)	P1^v—O2—Na1^xiv	113.9 (2)
O1^vi—Na1—O2^viii	176.8 (2)	P1—O2—Na1^xiv	113.9 (2)
O1—Na1—O2^viii	99.4 (2)	O2^v—O2—Na1^xv	32.20 (15)
O2^vii—Na1—O2^viii	83.8 (4)	As1^v—O2—Na1^xv	89.5 (3)
O1^vi—Na1—O3A^ix	83.0 (4)	P1^v—O2—Na1^xv	89.5 (3)
O1—Na1—O3A^ix	129.8 (4)	P1—O2—Na1^xv	89.5 (3)
O2^vii—Na1—O3A^ix	49.1 (4)	Na1^xiv—O2—Na1^xv	105.9 (3)
O2^viii—Na1—O3A^ix	99.2 (4)	O3B—O3A—P1	78 (2)
O1^vi—Na1—O3A^vii	83.0 (4)	O3B—O3A—Co1	77 (2)
O1—Na1—O3A^vii	129.8 (4)	P1—O3A—Co1	118.6 (9)
O2^vii—Na1—O3A^vii	49.1 (4)	O3B—O3A—Na1^xiv	150 (3)
O2^viii—Na1—O3A^vii	99.2 (4)	P1—O3A—Na1^xiv	114.5 (8)
O3A^ix—Na1—O3A^vii	92.0 (8)	Co1—O3A—Na1^xiv	115.6 (7)
O1^vi—Na1—O3A^i	129.8 (4)	O3B—O3A—Na2^xvi	40 (2)
O1—Na1—O3A^i	83.0 (4)	P1—O3A—Na2^xvi	88.1 (7)
O2^vii—Na1—O3A^i	99.2 (4)	Co1—O3A—Na2^xvi	104.7 (6)
O2^viii—Na1—O3A^i	49.1 (4)	Na1^xiv—O3A—Na2^xvi	110.9 (6)
O3A^ix—Na1—O3A^i	75.1 (8)	O3A—O3B—P1	76 (2)
O3A^vii—Na1—O3A^i	141.2 (8)	O3A—O3B—Co1	83 (2)
O1^vi—Na1—O3A^viii	129.8 (4)	P1—O3B—Co1	120.4 (12)
O1—Na1—O3A^viii	83.0 (4)	O3A—O3B—Na2^xvi	130 (3)
O2^vii—Na1—O3A^viii	99.2 (4)	P1—O3B—Na2^xvi	108.0 (10)
O2^viii—Na1—O3A^viii	49.1 (4)	Co1—O3B—Na2^xvi	127.5 (8)
O3A^ix—Na1—O3A^viii	141.2 (8)	P1—O3C—Co1	113 (2)
O3A^vii—Na1—O3A^viii	75.1 (8)	P1—O3C—Na2^xvi	98.4 (18)
O3A^i—Na1—O3A^viii	92.0 (8)	Co1—O3C—Na2^xvi	121 (2)
O1^vi—Na1—O3C^ix	86.1 (8)	P1—O3C—Na1^xiv	98.7 (19)
O1—Na1—O3C^ix	124.3 (9)	Co1—O3C—Na1^xiv	107.3 (18)
O2^vii—Na1—O3C^ix	55.0 (9)	Na2^xvi—O3C—Na1^xiv	115.5 (15)
O2^viii—Na1—O3C^ix	95.8 (8)

Symmetry codes: (i) y−1/2, −x+1/2, −z+1/2; (ii) −y+1/2, x+1/2, −z+1/2; (iii) −x, −y+1, z; (iv) y, x, z; (v) −x+1, −y+1, z; (vi) x, y, −z; (vii) −x+1/2, y−1/2, z−1/2; (viii) −x+1/2, y−1/2, −z+1/2; (ix) y−1/2, −x+1/2, z−1/2; (x) −y+1/2, x+1/2, z−1/2; (xi) −x+1/2, y+1/2, −z+1/2; (xii) −x+1/2, y+1/2, z−1/2; (xiii) −x+1, −y+1, −z; (xiv) −x+1/2, y+1/2, z+1/2; (xv) x+1/2, −y+1/2, −z+1/2; (xvi) −x+1/2, y−1/2, z+1/2.

(II) Disodium cobalt phosphorus arsenic heptaoxide

Crystal data

Na2CoP1.07As0.93O7	Dx = 3.340 Mg m^−3
Mr = 319.83	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P42/mnm	Cell parameters from 25 reflections
a = 7.8084 (10) Å	θ = 11.4–14.7°
c = 10.4329 (12) Å	µ = 7.91 mm^−1
V = 636.11 (18) Å^3	T = 293 K
Z = 4	Parallelepiped, blue
F(000) = 607	0.17 × 0.11 × 0.07 mm

Data collection

Enraf–Nonius CAD-4 diffractometer	305 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.129
Graphite monochromator	θmax = 27.0°, θmin = 3.3°
w/2θ scans	h = −9→1
Absorption correction: ψ scan (North et al., 1968)	k = −9→1
Tmin = 0.797, Tmax = 0.998	l = −13→13
1826 measured reflections	2 standard reflections every 120 min
404 independent reflections	intensity decay: 1.0%

Refinement

Refinement on F^2	48 parameters
Least-squares matrix: full	1 restraint
R[F^2 > 2σ(F^2)] = 0.046	w = 1/[σ^2(Fo^2) + (0.0503P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.100	(Δ/σ)max < 0.001
S = 1.09	Δρmax = 0.83 e Å^−3
404 reflections	Δρmin = −1.05 e Å^−3

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	Occ. (<1)
Co1	0.0000	0.5000	0.2500	0.0287 (5)
As1	0.36231 (8)	0.36231 (8)	0.28780 (11)	0.0236 (4)	0.467 (6)
P1	0.36231 (8)	0.36231 (8)	0.28780 (11)	0.0236 (4)	0.533 (6)
Na1	0.2007 (3)	0.2007 (3)	0.0000	0.0403 (11)
Na2	0.3604 (3)	0.6396 (3)	0.0000	0.0314 (11)
O1	0.3659 (4)	0.3659 (4)	0.1393 (6)	0.0361 (14)
O2	0.4630 (7)	0.5370 (7)	0.3463 (10)	0.029 (3)	0.5
O3A	0.196 (7)	0.425 (8)	0.393 (6)	0.033 (2)	0.11 (2)
O3B	0.181 (2)	0.3809 (19)	0.3458 (16)	0.033 (2)	0.432 (17)
O3C	0.200 (2)	0.4574 (19)	0.3540 (19)	0.033 (2)	0.45 (2)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Co1	0.0268 (5)	0.0268 (5)	0.0325 (11)	0.000	0.000	0.000
As1	0.0221 (4)	0.0221 (4)	0.0265 (8)	0.0026 (4)	0.0008 (3)	0.0008 (3)
P1	0.0221 (4)	0.0221 (4)	0.0265 (8)	0.0026 (4)	0.0008 (3)	0.0008 (3)
Na1	0.0389 (15)	0.0389 (15)	0.043 (3)	−0.0259 (19)	0.000	0.000
Na2	0.0283 (13)	0.0283 (13)	0.038 (3)	0.0063 (16)	0.000	0.000
O1	0.0346 (17)	0.0346 (17)	0.039 (4)	−0.013 (2)	−0.0024 (15)	−0.0024 (15)
O2	0.026 (3)	0.026 (3)	0.034 (7)	−0.003 (4)	0.008 (2)	−0.008 (2)
O3A	0.037 (4)	0.046 (7)	0.014 (5)	0.022 (6)	−0.002 (3)	0.001 (6)
O3B	0.037 (4)	0.046 (7)	0.014 (5)	0.022 (6)	−0.002 (3)	0.001 (6)
O3C	0.037 (4)	0.046 (7)	0.014 (5)	0.022 (6)	−0.002 (3)	0.001 (6)

Geometric parameters (Å, º)

Co1—O3C	1.933 (19)	Na1—O3A^xi	2.55 (6)
Co1—O3C^i	1.933 (19)	Na1—O3A^i	2.55 (6)
Co1—O3C^ii	1.933 (19)	Na1—O3C^xii	2.554 (16)
Co1—O3C^iii	1.933 (19)	Na1—O3C^x	2.554 (16)
Co1—O3B^i	1.965 (16)	Na1—O3C^i	2.554 (16)
Co1—O3B^ii	1.965 (16)	Na1—O3C^xi	2.554 (16)
Co1—O3B^iii	1.965 (16)	Na2—O3B^xiii	2.499 (17)
Co1—O3B	1.965 (16)	Na2—O3B^xiv	2.499 (17)
Co1—O3A	2.21 (5)	Na2—O3B^ii	2.499 (17)
Co1—O3A^i	2.21 (5)	Na2—O3B^xv	2.499 (17)
Co1—O3A^ii	2.21 (5)	Na2—O3A^xiii	2.53 (6)
Co1—O3A^iii	2.21 (5)	Na2—O3A^xiv	2.53 (6)
As1—O3B	1.546 (17)	Na2—O3A^ii	2.53 (6)
As1—O3B^iv	1.546 (17)	Na2—O3A^xv	2.53 (6)
As1—O1	1.549 (6)	Na2—O1^ix	2.585 (5)
As1—O3C	1.621 (17)	Na2—O1^v	2.585 (5)
As1—O3C^iv	1.621 (17)	Na2—O1^xvi	2.585 (5)
As1—O2^v	1.688 (4)	Na2—O1	2.585 (5)
As1—O2	1.688 (4)	O1—Na2^xvi	2.585 (5)
As1—O3A	1.77 (6)	O2—O2^v	0.817 (15)
As1—O3A^iv	1.77 (6)	O2—As1^v	1.688 (4)
As1—Na2^vi	3.309 (3)	O2—P1^v	1.688 (4)
As1—Na1^vii	3.482 (2)	O2—Na1^viii	2.417 (9)
As1—Na1^viii	3.482 (2)	O3A—O3B	0.61 (5)
Na1—O1^ix	2.332 (6)	O3A—Na2^vi	2.53 (6)
Na1—O1	2.332 (6)	O3A—Na1^viii	2.55 (6)
Na1—O2^x	2.417 (9)	O3B—O3C	0.623 (18)
Na1—O2^xi	2.417 (9)	O3B—Na2^vi	2.499 (17)
Na1—O3A^x	2.55 (6)	O3C—Na1^viii	2.554 (16)
Na1—O3A^xii	2.55 (6)	O3C—Na2^vi	2.950 (18)
O3C—Co1—O3C^i	108.4 (6)	O2^x—Na1—O3A^i	90.7 (13)
O3C—Co1—O3C^ii	108.4 (6)	O2^xi—Na1—O3A^i	55.4 (13)
O3C^i—Co1—O3C^ii	111.7 (11)	O3A^x—Na1—O3A^i	136 (2)
O3C—Co1—O3C^iii	111.7 (11)	O3A^xii—Na1—O3A^i	52 (3)
O3C^i—Co1—O3C^iii	108.4 (6)	O3A^xi—Na1—O3A^i	110 (3)
O3C^ii—Co1—O3C^iii	108.4 (6)	O1^ix—Na1—O3C^xii	82.7 (4)
O3C—Co1—O3B^i	123.0 (5)	O1—Na1—O3C^xii	128.0 (4)
O3C^i—Co1—O3B^i	18.4 (5)	O2^x—Na1—O3C^xii	51.0 (4)
O3C^ii—Co1—O3B^i	112.2 (5)	O2^xi—Na1—O3C^xii	99.3 (4)
O3C^iii—Co1—O3B^i	91.5 (7)	O3A^x—Na1—O3C^xii	103.3 (15)
O3C—Co1—O3B^ii	91.5 (7)	O3A^xii—Na1—O3C^xii	10.7 (12)
O3C^i—Co1—O3B^ii	112.2 (5)	O3A^xi—Na1—O3C^xii	138.6 (11)
O3C^ii—Co1—O3B^ii	18.4 (5)	O3A^i—Na1—O3C^xii	62.5 (16)
O3C^iii—Co1—O3B^ii	123.0 (5)	O1^ix—Na1—O3C^x	82.7 (4)
O3B^i—Co1—O3B^ii	118.9 (10)	O1—Na1—O3C^x	128.0 (4)
O3C—Co1—O3B^iii	112.2 (5)	O2^x—Na1—O3C^x	51.0 (4)
O3C^i—Co1—O3B^iii	123.0 (5)	O2^xi—Na1—O3C^x	99.3 (4)
O3C^ii—Co1—O3B^iii	91.5 (7)	O3A^x—Na1—O3C^x	10.7 (12)
O3C^iii—Co1—O3B^iii	18.4 (5)	O3A^xii—Na1—O3C^x	103.3 (15)
O3B^i—Co1—O3B^iii	105.0 (4)	O3A^xi—Na1—O3C^x	62.5 (16)
O3B^ii—Co1—O3B^iii	105.0 (4)	O3A^i—Na1—O3C^x	138.6 (11)
O3C—Co1—O3B	18.4 (5)	O3C^xii—Na1—O3C^x	95.4 (9)
O3C^i—Co1—O3B	91.5 (7)	O1^ix—Na1—O3C^i	128.0 (4)
O3C^ii—Co1—O3B	123.0 (5)	O1—Na1—O3C^i	82.7 (4)
O3C^iii—Co1—O3B	112.2 (5)	O2^x—Na1—O3C^i	99.3 (4)
O3B^i—Co1—O3B	105.0 (4)	O2^xi—Na1—O3C^i	51.0 (4)
O3B^ii—Co1—O3B	105.0 (4)	O3A^x—Na1—O3C^i	138.6 (11)
O3B^iii—Co1—O3B	118.9 (10)	O3A^xii—Na1—O3C^i	62.5 (16)
O3C—Co1—O3A	10.8 (17)	O3A^xi—Na1—O3C^i	103.3 (15)
O3C^i—Co1—O3A	106.5 (16)	O3A^i—Na1—O3C^i	10.7 (12)
O3C^ii—Co1—O3A	118.2 (19)	O3C^xii—Na1—O3C^i	73.2 (9)
O3C^iii—Co1—O3A	103.1 (16)	O3C^x—Na1—O3C^i	143.6 (8)
O3B^i—Co1—O3A	118.7 (17)	O1^ix—Na1—O3C^xi	128.0 (4)
O3B^ii—Co1—O3A	101.8 (17)	O1—Na1—O3C^xi	82.7 (4)
O3B^iii—Co1—O3A	106.2 (16)	O2^x—Na1—O3C^xi	99.3 (4)
O3B—Co1—O3A	15.5 (13)	O2^xi—Na1—O3C^xi	51.0 (4)
O3C—Co1—O3A^i	118.2 (18)	O3A^x—Na1—O3C^xi	62.5 (16)
O3C^i—Co1—O3A^i	10.8 (17)	O3A^xii—Na1—O3C^xi	138.6 (11)
O3C^ii—Co1—O3A^i	103.1 (16)	O3A^xi—Na1—O3C^xi	10.7 (12)
O3C^iii—Co1—O3A^i	106.5 (16)	O3A^i—Na1—O3C^xi	103.3 (15)
O3B^i—Co1—O3A^i	15.5 (13)	O3C^xii—Na1—O3C^xi	143.6 (8)
O3B^ii—Co1—O3A^i	106.2 (16)	O3C^x—Na1—O3C^xi	73.2 (9)
O3B^iii—Co1—O3A^i	118.7 (17)	O3C^i—Na1—O3C^xi	95.4 (9)
O3B—Co1—O3A^i	101.8 (17)	O3B^xiii—Na2—O3B^xiv	102.7 (8)
O3A—Co1—O3A^i	117.0 (16)	O3B^xiii—Na2—O3B^ii	80.2 (7)
O3C—Co1—O3A^ii	106.5 (16)	O3B^xiv—Na2—O3B^ii	52.4 (7)
O3C^i—Co1—O3A^ii	103.1 (16)	O3B^xiii—Na2—O3B^xv	52.4 (7)
O3C^ii—Co1—O3A^ii	10.8 (17)	O3B^xiv—Na2—O3B^xv	80.2 (7)
O3C^iii—Co1—O3A^ii	118.2 (18)	O3B^ii—Na2—O3B^xv	102.7 (8)
O3B^i—Co1—O3A^ii	106.2 (16)	O3B^xiii—Na2—O3A^xiii	14.0 (12)
O3B^ii—Co1—O3A^ii	15.5 (13)	O3B^xiv—Na2—O3A^xiii	92.3 (14)
O3B^iii—Co1—O3A^ii	101.8 (17)	O3B^ii—Na2—O3A^xiii	66.3 (14)
O3B—Co1—O3A^ii	118.7 (17)	O3B^xv—Na2—O3A^xiii	58.1 (13)
O3A—Co1—O3A^ii	117.0 (17)	O3B^xiii—Na2—O3A^xiv	92.3 (14)
O3A^i—Co1—O3A^ii	95 (3)	O3B^xiv—Na2—O3A^xiv	14.0 (12)
O3C—Co1—O3A^iii	103.1 (16)	O3B^ii—Na2—O3A^xiv	58.1 (13)
O3C^i—Co1—O3A^iii	118.2 (19)	O3B^xv—Na2—O3A^xiv	66.3 (14)
O3C^ii—Co1—O3A^iii	106.5 (16)	O3A^xiii—Na2—O3A^xiv	84 (3)
O3C^iii—Co1—O3A^iii	10.8 (17)	O3B^xiii—Na2—O3A^ii	66.3 (14)
O3B^i—Co1—O3A^iii	101.8 (17)	O3B^xiv—Na2—O3A^ii	58.1 (13)
O3B^ii—Co1—O3A^iii	118.7 (17)	O3B^ii—Na2—O3A^ii	14.0 (12)
O3B^iii—Co1—O3A^iii	15.5 (13)	O3B^xv—Na2—O3A^ii	92.3 (14)
O3B—Co1—O3A^iii	106.2 (16)	O3A^xiii—Na2—O3A^ii	52 (3)
O3A—Co1—O3A^iii	95 (3)	O3A^xiv—Na2—O3A^ii	60 (2)
O3A^i—Co1—O3A^iii	117.0 (17)	O3B^xiii—Na2—O3A^xv	58.1 (13)
O3A^ii—Co1—O3A^iii	117.0 (17)	O3B^xiv—Na2—O3A^xv	66.3 (14)
O3B—As1—O3B^iv	91.1 (11)	O3B^ii—Na2—O3A^xv	92.3 (14)
O3B—As1—O1	113.9 (6)	O3B^xv—Na2—O3A^xv	14.0 (12)
O3B^iv—As1—O1	113.9 (6)	O3A^xiii—Na2—O3A^xv	60 (2)
O3B—As1—O3C	22.5 (7)	O3A^xiv—Na2—O3A^xv	52 (3)
O3B^iv—As1—O3C	109.0 (8)	O3A^ii—Na2—O3A^xv	84 (3)
O1—As1—O3C	115.6 (7)	O3B^xiii—Na2—O1^ix	76.0 (4)
O3B—As1—O3C^iv	109.0 (8)	O3B^xiv—Na2—O1^ix	171.0 (4)
O3B^iv—As1—O3C^iv	22.5 (7)	O3B^ii—Na2—O1^ix	118.8 (4)
O1—As1—O3C^iv	115.6 (7)	O3B^xv—Na2—O1^ix	105.3 (4)
O3C—As1—O3C^iv	122.2 (14)	O3A^xiii—Na2—O1^ix	84.8 (13)
O3B—As1—O2^v	123.7 (7)	O3A^xiv—Na2—O1^ix	168.2 (13)
O3B^iv—As1—O2^v	102.1 (6)	O3A^ii—Na2—O1^ix	113.9 (12)
O1—As1—O2^v	109.8 (4)	O3A^xv—Na2—O1^ix	118.9 (13)
O3C—As1—O2^v	105.2 (7)	O3B^xiii—Na2—O1^v	171.0 (4)
O3C^iv—As1—O2^v	80.7 (6)	O3B^xiv—Na2—O1^v	76.0 (4)
O3B—As1—O2	102.1 (6)	O3B^ii—Na2—O1^v	105.3 (4)
O3B^iv—As1—O2	123.7 (7)	O3B^xv—Na2—O1^v	118.8 (4)
O1—As1—O2	109.8 (4)	O3A^xiii—Na2—O1^v	168.2 (13)
O3C—As1—O2	80.7 (6)	O3A^xiv—Na2—O1^v	84.8 (13)
O3C^iv—As1—O2	105.2 (7)	O3A^ii—Na2—O1^v	118.9 (13)
O2^v—As1—O2	28.0 (5)	O3A^xv—Na2—O1^v	113.9 (12)
O3B—As1—O3A	19.9 (18)	O1^ix—Na2—O1^v	106.79 (18)
O3B^iv—As1—O3A	95 (2)	O3B^xiii—Na2—O1^xvi	105.3 (4)
O1—As1—O3A	128.9 (18)	O3B^xiv—Na2—O1^xvi	118.8 (4)
O3C—As1—O3A	15.4 (17)	O3B^ii—Na2—O1^xvi	171.0 (4)
O3C^iv—As1—O3A	107 (2)	O3B^xv—Na2—O1^xvi	76.0 (4)
O2^v—As1—O3A	104 (2)	O3A^xiii—Na2—O1^xvi	118.9 (13)
O2—As1—O3A	84 (2)	O3A^xiv—Na2—O1^xvi	113.9 (12)
O3B—As1—O3A^iv	95 (2)	O3A^ii—Na2—O1^xvi	168.2 (13)
O3B^iv—As1—O3A^iv	19.9 (18)	O3A^xv—Na2—O1^xvi	84.8 (13)
O1—As1—O3A^iv	128.9 (18)	O1^ix—Na2—O1^xvi	69.92 (18)
O3C—As1—O3A^iv	107 (2)	O1^v—Na2—O1^xvi	68.4 (2)
O3C^iv—As1—O3A^iv	15.4 (17)	O3B^xiii—Na2—O1	118.8 (4)
O2^v—As1—O3A^iv	84 (2)	O3B^xiv—Na2—O1	105.3 (4)
O2—As1—O3A^iv	104 (2)	O3B^ii—Na2—O1	76.0 (4)
O3A—As1—O3A^iv	91 (4)	O3B^xv—Na2—O1	171.0 (4)
O3B—As1—Na2^vi	46.1 (6)	O3A^xiii—Na2—O1	113.9 (12)
O3B^iv—As1—Na2^vi	46.1 (6)	O3A^xiv—Na2—O1	118.9 (13)
O1—As1—Na2^vi	133.44 (16)	O3A^ii—Na2—O1	84.8 (13)
O3C—As1—Na2^vi	63.0 (6)	O3A^xv—Na2—O1	168.2 (13)
O3C^iv—As1—Na2^vi	63.0 (6)	O1^ix—Na2—O1	68.4 (2)
O2^v—As1—Na2^vi	115.3 (3)	O1^v—Na2—O1	69.92 (18)
O2—As1—Na2^vi	115.3 (3)	O1^xvi—Na2—O1	106.79 (18)
O3A—As1—Na2^vi	49 (2)	As1—O1—Na1	127.1 (3)
O3A^iv—As1—Na2^vi	49 (2)	As1—O1—Na2	125.21 (18)
O3B—As1—Na1^vii	117.3 (6)	Na1—O1—Na2	95.60 (19)
O3B^iv—As1—Na1^vii	63.3 (6)	As1—O1—Na2^xvi	125.21 (18)
O1—As1—Na1^vii	128.65 (10)	Na1—O1—Na2^xvi	95.60 (19)
O3C—As1—Na1^vii	112.7 (7)	Na2—O1—Na2^xvi	73.21 (18)
O3C^iv—As1—Na1^vii	43.2 (6)	O2^v—O2—As1	76.0 (2)
O2^v—As1—Na1^vii	39.0 (2)	O2^v—O2—As1^v	76.0 (2)
O2—As1—Na1^vii	62.0 (3)	As1—O2—As1^v	128.5 (6)
O3A—As1—Na1^vii	101.7 (18)	O2^v—O2—P1^v	76.0 (2)
O3A^iv—As1—Na1^vii	45 (2)	As1—O2—P1^v	128.5 (6)
Na2^vi—As1—Na1^vii	84.21 (4)	As1^v—O2—P1^v	0.00 (8)
O3B—As1—Na1^viii	63.3 (6)	O2^v—O2—Na1^viii	138.4 (2)
O3B^iv—As1—Na1^viii	117.3 (6)	As1—O2—Na1^viii	114.9 (2)
O1—As1—Na1^viii	128.65 (10)	As1^v—O2—Na1^viii	114.9 (2)
O3C—As1—Na1^viii	43.2 (6)	P1^v—O2—Na1^viii	114.9 (2)
O3C^iv—As1—Na1^viii	112.7 (7)	O3B—O3A—As1	59 (5)
O2^v—As1—Na1^viii	62.0 (3)	O3B—O3A—Co1	59 (5)
O2—As1—Na1^viii	39.0 (2)	As1—O3A—Co1	99 (3)
O3A—As1—Na1^viii	45 (2)	O3B—O3A—Na2^vi	80 (6)
O3A^iv—As1—Na1^viii	101.7 (18)	As1—O3A—Na2^vi	99 (2)
Na2^vi—As1—Na1^viii	84.21 (4)	Co1—O3A—Na2^vi	114 (3)
Na1^vii—As1—Na1^viii	79.06 (10)	O3B—O3A—Na1^viii	152 (8)
O1^ix—Na1—O1	77.1 (3)	As1—O3A—Na1^viii	106 (3)
O1^ix—Na1—O2^x	99.9 (3)	Co1—O3A—Na1^viii	107 (2)
O1—Na1—O2^x	177.0 (3)	Na2^vi—O3A—Na1^viii	127 (2)
O1^ix—Na1—O2^xi	177.0 (3)	O3A—O3B—O3C	46 (5)
O1—Na1—O2^xi	99.9 (3)	O3A—O3B—As1	101 (6)
O2^x—Na1—O2^xi	83.2 (5)	O3C—O3B—As1	86 (3)
O1^ix—Na1—O3A^x	91.0 (12)	O3A—O3B—Co1	106 (5)
O1—Na1—O3A^x	124.3 (13)	O3C—O3B—Co1	78 (3)
O2^x—Na1—O3A^x	55.4 (13)	As1—O3B—Co1	120.3 (10)
O2^xi—Na1—O3A^x	90.7 (13)	O3A—O3B—Na2^vi	86 (6)
O1^ix—Na1—O3A^xii	91.0 (12)	O3C—O3B—Na2^vi	132 (3)
O1—Na1—O3A^xii	124.3 (13)	As1—O3B—Na2^vi	107.4 (7)
O2^x—Na1—O3A^xii	55.4 (13)	Co1—O3B—Na2^vi	126.2 (8)
O2^xi—Na1—O3A^xii	90.7 (13)	O3B—O3C—As1	72 (3)
O3A^x—Na1—O3A^xii	110 (3)	O3B—O3C—Co1	84 (3)
O1^ix—Na1—O3A^xi	124.3 (13)	As1—O3C—Co1	118.1 (10)
O1—Na1—O3A^xi	91.0 (12)	O3B—O3C—Na1^viii	150 (3)
O2^x—Na1—O3A^xi	90.7 (13)	As1—O3C—Na1^viii	111.1 (9)
O2^xi—Na1—O3A^xi	55.4 (13)	Co1—O3C—Na1^viii	116.8 (7)
O3A^x—Na1—O3A^xi	52 (3)	O3B—O3C—Na2^vi	39 (3)
O3A^xii—Na1—O3A^xi	136 (2)	As1—O3C—Na2^vi	87.7 (6)
O1^ix—Na1—O3A^i	124.3 (13)	Co1—O3C—Na2^vi	107.7 (7)
O1—Na1—O3A^i	91.0 (12)	Na1^viii—O3C—Na2^vi	111.5 (7)

Symmetry codes: (i) y−1/2, −x+1/2, −z+1/2; (ii) −y+1/2, x+1/2, −z+1/2; (iii) −x, −y+1, z; (iv) y, x, z; (v) −x+1, −y+1, z; (vi) −x+1/2, y−1/2, z+1/2; (vii) x+1/2, −y+1/2, −z+1/2; (viii) −x+1/2, y+1/2, z+1/2; (ix) x, y, −z; (x) −x+1/2, y−1/2, z−1/2; (xi) −x+1/2, y−1/2, −z+1/2; (xii) y−1/2, −x+1/2, z−1/2; (xiii) −y+1/2, x+1/2, z−1/2; (xiv) −x+1/2, y+1/2, −z+1/2; (xv) −x+1/2, y+1/2, z−1/2; (xvi) −x+1, −y+1, −z.