Crystal structure of a silver-, cobalt- and iron-based phosphate with an alluaudite-like structure: Ag1.655Co1.64Fe1.36(PO4)3

Bouraima, A.; Makani, T.; Assani, A.; Saadi, M.; El Ammari, L.

doi:10.1107/S205698901700740X

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Volume 73| Part 6| June 2017| Pages 890-892

https://doi.org/10.1107/S205698901700740X

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Crystal structure of a silver-, cobalt- and iron-based phosphate with an alluaudite-like structure: Ag_1.655Co_1.64Fe_1.36(PO₄)₃

Adam Bouraima,^a,^b ^* Thomas Makani,^b Abderrazzak Assani,^a Mohamed Saadi ^a and Lahcen El Ammari ^a

^aLaboratoire de Chimie du Solide Appliquée, Faculty of Sciences, Mohammed V University in Rabat, Avenue Ibn Battouta, BP 1014, Rabat, Morocco, and ^bDépartement de Chimie, Faculté des Sciences, Université des Sciences et Techniques de Masuku, BP 943, Franceville, Gabon
^*Correspondence e-mail: adam_bouraima@yahoo.fr

Edited by E. F. C. Herdtweck, Technische Universität München, Germany (Received 20 April 2017; accepted 19 May 2017; online 26 May 2017)

The new silver-, cobalt- and iron-based phosphate, silver cobalt iron tris(orthophosphate), Ag_1.655Co_1.64Fe_1.36(PO₄)₃, was synthesized by solid-state reactions. Its structure is isotypic to that of Na₂Co₂Fe(PO₄)₃, and belongs to the alluaudite family, with a partial cationic disorder, the Ag^I atoms being located on an inversion centre and twofold rotation axis sites (Wyckoff positions 4a and 4e), with partial occupancies of 0.885 (2) and 0.7688 (19), respectively. One of the two P atoms in the asymmetric unit completely fills one 4e site while the Co and Fe atoms fill another 4e site, with partial occupancies of 0.86 (5) and 0.14 (5), respectively. The remaining Co²⁺ and Fe³⁺ cations are distributed on a general position, 8f, in a 0.39 (4):0.61 (4) ratio. All O atoms and the other P atoms are in general positions. The structure is built up from zigzag chains of edge-sharing [MO₆] (M = Fe/Co) octahedra stacked parallel to [101]. These chains are linked together through PO₄ tetrahedra, forming polyhedral sheets perpendicular to [010]. The resulting framework displays two types of channels running along [001], in which the Ag^I atoms (coordination number eight) are located.

Keywords: crystal structure; Ag_1.655Co_1.64Fe_1.36(PO₄)₃; transition metal phosphate; solid-state reaction synthesis; alluaudite-like structure.

CCDC reference: 1551181

1. Chemical context

Compounds belonging to the large alluaudite structural family (Moore, 1971 ; Moore & Ito, 1979 ; Hatert et al., 2000 , 2004 ) have been of continuing interest owing to their open-framework architecture, with hexagonal-shaped channels, and their physical properties. This fact is amply justified by their practical applications, for example as corrosion inhibitors, passivators of metal surfaces, and catalysts (Korzenski et al., 1999 ). In addition, interest in alluaudite phosphates with monovalent cations has continued to grow in the electrochemical field, where they have applications as positive electrodes in lithium and sodium batteries (Trad et al., 2010 ). Accordingly, our attention is mostly focused on the elaboration and structural characterization of new alluaudite-type phosphates within the A₂O–MO–P₂O₅ systems (A = monovalent cation M = divalent cation). For instance, most recently, the hydrothermal investigation of the Na₂O–MO–P₂O₅ pseudo-ternary system has allowed the isolation of the sodium- and magnesium-based alluaudite phosphate NaMg₃(PO₄)(HPO₄)₂ (Ould Saleck et al., 2015 ). On the other hand, within the Na₂O–CoO–Fe₂O₃–P₂O₅ and Na₂O–ZnO–Fe₂O₃–P₂O₅ pseudo-quaternary systems, solid-state synthesis has allowed Na₂Co₂Fe(PO₄)₃ (Bouraima et al., 2015 ) and Na_1.67Zn_1.67Fe_1.33(PO₄)₃ (Khmiyas et al., 2015 ) to be obtained. With the same objective, a new silver-, cobalt- and iron-based alluaudite-type phosphate, namely Ag_1.655Co_1.64Fe_1.36(PO₄)₃, has been synthesized by means of solid-state reactions and characterized by single crystal X-ray diffraction.

2. Structural commentary

In the new isolated compound, either cobalt or iron atoms are distributed in the two octahedral sites while the phosphorus atoms are tetrahedrally coordinated, as shown in Fig. 1. The structure is built up from two edge-sharing [(Co1/Fe1)O₆] octahedra, leading to the formation of [(Co1/Fe1)₂O₁₀] dimers. Those dimers are connected by a common edge to [(Fe2/Co2)O₆] octahedra, forming an infinite chain (Fig. 2). The junction between these chains is ensured by sharing vertices with the PO₄ tetrahedra so as to form an open layer perpendicular to [010] (Fig. 3). The three-dimensional framework resulting from the stacking of the sheets along the b-axis direction delimits channels parallel to [001] in which the Ag⁺ cations are accommodated, as shown in Fig. 4.

Figure 1
The principal building units in the structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (i) x, −y + 1, z + $[{1\over 2}]$ ; (ii) −x + 1, y, −z + $[{1\over 2}]$ ; (iii) −x + 1, −y + 1, −z + 1; (iv) −x + 2, y, −z + $[{3\over 2}]$ ; (v) −x + 2, −y + 1, −z + 1; (vi) x + $[{1\over 2}]$ , −y + $[{1\over 2}]$ , z + $[{1\over 2}]$ ; (vii) −x + $[{3\over 2}]$ , −y + $[{1\over 2}]$ , −z + 1; (viii) x, −y + 1, z − $[{1\over 2}]$ ; (ix) −x + $[{3\over 2}]$ , y − $[{1\over 2}]$ , −z + $[{1\over 2}]$ ; (x) x + $[{1\over 2}]$ , −y + $[{3\over 2}]$ , z + $[{1\over 2}]$ ; (xi) −x + $[{3\over 2}]$ , −y + $[{3\over 2}]$ , −z + 1; (xii) −x + $[{3\over 2}]$ , y + $[{1\over 2}]$ , −z + $[{1\over 2}]$ ; (xiii) x + $[{1\over 2}]$ , y + $[{1\over 2}]$ , z + 1.]

Figure 2
Edge-sharing [(Fe/Co)O₆] octahedra forming a layer parallel to [101].

Figure 3
A view along [010], showing a layer resulting from the connection of chains via vertices of PO₄ tetrahedra and [FeO₆] octahedra.

Figure 4
Polyhedral representation of Ag_1.655Co_1.64Fe_1.36(PO₄)₃, showing channels running along [001].

3. Comparison with a related structure

It is worth mentioning that the distribution of metallic cations observed in the case of the silver–cobalt–iron-based phosphate is not encountered in the sodium homologue. Hence, in the title silver-based phosphate, the octahedral M1 site (Wyckoff position 8f) is occupied to 60% by Fe1 and to 40% by Co1. The octahedrally surrounded M2 site (Wyckoff position 4e) is essentially occupied by Fe2 atoms (43%) along with a small amount of Co2 (7%). However, in the Na₂Co₂Fe(PO₄)₃ phosphate, the M1 and M2 sites are entirely occupied by Fe and Co atoms, respectively. For the mixed sites, the occupancy rate was refined without any constraint. The results of the refinements are in good agreement with the electrical neutrality of the compound and calculations of the bond-valence sums of the atoms in the structure (Brown & Altermatt, 1985 ). Accordingly, in the silver-based phosphate, the cations at the M1 site form double octahedra [(Fe1/Co1)₂O₁₀] alternating with [(Fe2/Co2)O₆] octahedra, while in the sodium homologue phosphate, the obtained [Co₂O₁₀] double octahedra alternate with [FeO₆] octahedra (Fig. 4). Moreover, both the Ag1 and Ag2 atoms are located in channels, surrounded by eight oxygen atoms with Ag1—O bond lengths between 2.3320 (13) Å and 2.9176 (13) Å, whereas Ag2—O bond lengths are in the range 2.4733 (13)–2.9035 (12) Å. The structure of the title phosphate is isotypic to that of Na₂Co₂Fe(PO₄)₃ (Bouraima et al., 2015) and Na_1.67Zn_1.67Fe_1.33(PO₄)₃ (Khmiyas et al., 2015).

4. Synthesis and crystallization

The title compound was isolated from solid-state reactions in air by mixing nitrates of silver, cobalt and iron with phosphoric acid. The various precursors are taken in the molar ratio Ag:Co:Fe:P = 2:2:1:3. The mixture was stirred at room temperature overnight. After different heat treatments in a platinum crucible at up to 873 K, the reaction mixture was heated to the melting temperature of 1221 K. The molten product was then cooled to room temperature at a rate of 5 K h⁻¹. Brown homogeneous crystals corresponding to the title compound of a suitable size for X-ray diffraction were obtained.

5. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. The maximum and minimum residual electron densities in the final Fourier map are 0.68 and 0.55 Å from Ag1 and Ag2, respectively.

Table 1
Experimental details

Crystal data
Chemical formula	Ag_1.655Co_1.64Fe_1.36(PO₄)₃
M_r	2544.10
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	296
a, b, c (Å)	11.8680 (3), 12.5514 (3), 6.4386 (2)
β (°)	114.012 (1)
V (Å³)	876.09 (4)
Z	1
Radiation type	Mo Kα
μ (mm⁻¹)	9.51
Crystal size (mm)	0.31 × 0.26 × 0.22

Data collection
Diffractometer	Bruker X8 APEX
Absorption correction	Multi-scan (SADABS; Krause et al., 2015 )
T_min, T_max	0.066, 0.124
No. of measured, independent and observed [I > 2σ(I)] reflections	13097, 2137, 2079
R_int	0.030
(sin θ/λ)_max (Å⁻¹)	0.833

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.020, 0.047, 1.19
No. of reflections	2137
No. of parameters	99
Δρ_max, Δρ_min (e Å⁻³)	1.47, −0.92
Computer programs: APEX2 aand SAINT (Bruker, 2009 ), SHELXT2014 (Sheldrick, 2015a ), SHELXL2014 (Sheldrick, 2015b ), ORTEP-3 for Windows (Farrugia, 2012 ), DIAMOND (Brandenburg, 2006 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 1551181

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S205698901700740X/hp2074sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S205698901700740X/hp2074Isup2.hkl

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Silver cobalt iron tris(orthophosphate) top

Crystal data top

Ag_1.655Co_1.64Fe_1.36(PO₄)₃	F(000) = 1194
M_r = 2544.10	D_x = 4.822 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 11.8680 (3) Å	Cell parameters from 2137 reflections
b = 12.5514 (3) Å	θ = 3.3–36.3°
c = 6.4386 (2) Å	µ = 9.51 mm⁻¹
β = 114.012 (1)°	T = 296 K
V = 876.09 (4) Å³	Block, brown
Z = 1	0.31 × 0.26 × 0.22 mm

Data collection top

Bruker X8 APEX diffractometer	2137 independent reflections
Radiation source: fine-focus sealed tube	2079 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.030
φ and ω scans	θ_max = 36.3°, θ_min = 3.3°
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	h = −19→19
T_min = 0.066, T_max = 0.124	k = −20→20
13097 measured reflections	l = −10→10

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.0121P)² + 3.2851P] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.020	(Δ/σ)_max = 0.001
wR(F²) = 0.047	Δρ_max = 1.47 e Å⁻³
S = 1.19	Δρ_min = −0.92 e Å⁻³
2137 reflections	Extinction correction: SHELXL2014 (Sheldrick, 2015b), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
99 parameters	Extinction coefficient: 0.00102 (10)

Special details top

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 (Å²) top

	x	y	z	U_iso*/U_eq	Occ. (<1)
Ag1	0.5000	0.5000	0.5000	0.01952 (7)	0.885 (2)
Ag2	1.0000	0.48916 (3)	0.7500	0.02408 (10)	0.7688 (19)
Fe1	0.78227 (2)	0.34311 (2)	0.37115 (3)	0.00565 (6)	0.61 (4)
Co1	0.78227 (2)	0.34311 (2)	0.37115 (3)	0.00565 (6)	0.39 (4)
Fe2	1.0000	0.76503 (2)	0.7500	0.00714 (8)	0.14 (5)
Co2	1.0000	0.76503 (2)	0.7500	0.00714 (8)	0.86 (5)
P1	0.76272 (3)	0.61138 (3)	0.37428 (6)	0.00502 (8)
P2	0.5000	0.28909 (4)	0.2500	0.00535 (10)
O1	0.77807 (11)	0.67841 (10)	0.18620 (19)	0.00908 (19)
O2	0.81856 (12)	0.49999 (9)	0.3820 (2)	0.0112 (2)
O3	0.62598 (11)	0.60711 (11)	0.3280 (2)	0.0135 (2)
O4	0.83676 (12)	0.66524 (9)	0.60788 (19)	0.00917 (19)
O5	0.45841 (10)	0.21873 (10)	0.03381 (18)	0.00821 (19)
O6	0.60284 (12)	0.36401 (10)	0.2530 (2)	0.0122 (2)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ag1	0.02917 (14)	0.00879 (9)	0.01123 (10)	−0.00389 (7)	−0.00138 (8)	−0.00128 (6)
Ag2	0.01069 (12)	0.02795 (16)	0.02519 (15)	0.000	−0.00133 (10)	0.000
Fe1	0.00485 (9)	0.00657 (9)	0.00575 (9)	0.00037 (6)	0.00240 (6)	0.00058 (6)
Co1	0.00485 (9)	0.00657 (9)	0.00575 (9)	0.00037 (6)	0.00240 (6)	0.00058 (6)
Fe2	0.00620 (12)	0.00833 (13)	0.00796 (13)	0.000	0.00398 (10)	0.000
Co2	0.00620 (12)	0.00833 (13)	0.00796 (13)	0.000	0.00398 (10)	0.000
P1	0.00488 (15)	0.00490 (15)	0.00521 (15)	0.00006 (11)	0.00198 (11)	0.00022 (10)
P2	0.00397 (19)	0.0071 (2)	0.00466 (19)	0.000	0.00138 (16)	0.000
O1	0.0101 (5)	0.0112 (5)	0.0062 (4)	−0.0001 (4)	0.0036 (4)	0.0020 (3)
O2	0.0118 (5)	0.0070 (4)	0.0144 (5)	0.0024 (4)	0.0048 (4)	−0.0013 (4)
O3	0.0067 (4)	0.0125 (5)	0.0221 (6)	0.0007 (4)	0.0066 (4)	0.0031 (4)
O4	0.0127 (5)	0.0083 (4)	0.0062 (4)	−0.0011 (4)	0.0034 (4)	−0.0013 (3)
O5	0.0064 (4)	0.0124 (5)	0.0053 (4)	−0.0011 (4)	0.0018 (3)	−0.0017 (3)
O6	0.0085 (5)	0.0119 (5)	0.0166 (5)	−0.0036 (4)	0.0054 (4)	0.0007 (4)

Geometric parameters (Å, º) top

Ag1—O6ⁱ	2.3320 (13)	Fe1—O4^viii	2.0481 (12)
Ag1—O6ⁱⁱ	2.3320 (13)	Fe1—O1ⁱ	2.0669 (11)
Ag1—O3ⁱ	2.4356 (14)	Fe1—O5^vi	2.0705 (12)
Ag1—O3ⁱⁱ	2.4356 (14)	Fe1—O1^ix	2.1695 (12)
Ag1—O3ⁱⁱⁱ	2.5724 (13)	Fe2—O3^x	2.1099 (13)
Ag1—O3	2.5725 (13)	Fe2—O3^xi	2.1099 (13)
Ag1—O6ⁱⁱⁱ	2.9176 (13)	Fe2—O5^xii	2.1575 (11)
Ag1—O6	2.9176 (13)	Fe2—O5^xiii	2.1575 (11)
Ag2—O2^iv	2.4733 (13)	Fe2—O4^iv	2.1717 (12)
Ag2—O2	2.4733 (13)	Fe2—O4	2.1717 (12)
Ag2—O2ⁱ	2.6204 (13)	P1—O3	1.5270 (13)
Ag2—O2^v	2.6204 (13)	P1—O2	1.5393 (12)
Ag2—O4	2.8341 (12)	P1—O1	1.5451 (12)
Ag2—O4^iv	2.8341 (12)	P1—O4	1.5543 (12)
Ag2—O5^vi	2.9035 (13)	P2—O6ⁱⁱ	1.5346 (13)
Ag2—O5^vii	2.9035 (12)	P2—O6	1.5346 (13)
Fe1—O6	1.9656 (13)	P2—O5ⁱⁱ	1.5498 (12)
Fe1—O2	2.0108 (12)	P2—O5	1.5498 (12)

O6ⁱ—Ag1—O6ⁱⁱ	180.00 (4)	O2—Ag2—O1ⁱ	64.62 (4)
O6ⁱ—Ag1—O3ⁱ	80.58 (4)	O2ⁱ—Ag2—O1ⁱ	49.21 (3)
O6ⁱⁱ—Ag1—O3ⁱ	99.42 (4)	O2^v—Ag2—O1ⁱ	136.08 (3)
O6ⁱ—Ag1—O3ⁱⁱ	99.42 (4)	O4—Ag2—O1ⁱ	92.94 (3)
O6ⁱⁱ—Ag1—O3ⁱⁱ	80.58 (4)	O4^iv—Ag2—O1ⁱ	162.54 (3)
O3ⁱ—Ag1—O3ⁱⁱ	180.0	O5^vi—Ag2—O1ⁱ	52.36 (3)
O6ⁱ—Ag1—O3ⁱⁱⁱ	108.21 (5)	O5^vii—Ag2—O1ⁱ	56.78 (3)
O6ⁱⁱ—Ag1—O3ⁱⁱⁱ	71.79 (5)	O2^iv—Ag2—O1^v	64.62 (4)
O3ⁱ—Ag1—O3ⁱⁱⁱ	66.27 (5)	O2—Ag2—O1^v	119.96 (4)
O3ⁱⁱ—Ag1—O3ⁱⁱⁱ	113.73 (5)	O2ⁱ—Ag2—O1^v	136.08 (3)
O6ⁱ—Ag1—O3	71.79 (5)	O2^v—Ag2—O1^v	49.21 (3)
O6ⁱⁱ—Ag1—O3	108.21 (5)	O4—Ag2—O1^v	162.54 (3)
O3ⁱ—Ag1—O3	113.73 (5)	O4^iv—Ag2—O1^v	92.94 (3)
O3ⁱⁱ—Ag1—O3	66.27 (5)	O5^vi—Ag2—O1^v	56.78 (3)
O3ⁱⁱⁱ—Ag1—O3	180.0	O5^vii—Ag2—O1^v	52.36 (3)
O6ⁱ—Ag1—O6ⁱⁱⁱ	53.64 (5)	O6—Fe1—O2	93.77 (5)
O6ⁱⁱ—Ag1—O6ⁱⁱⁱ	126.36 (5)	O6—Fe1—O4^viii	110.10 (5)
O3ⁱ—Ag1—O6ⁱⁱⁱ	95.49 (4)	O2—Fe1—O4^viii	86.76 (5)
O3ⁱⁱ—Ag1—O6ⁱⁱⁱ	84.51 (4)	O6—Fe1—O1ⁱ	86.70 (5)
O3ⁱⁱⁱ—Ag1—O6ⁱⁱⁱ	68.02 (4)	O2—Fe1—O1ⁱ	100.62 (5)
O3—Ag1—O6ⁱⁱⁱ	111.98 (4)	O4^viii—Fe1—O1ⁱ	161.33 (5)
O6ⁱ—Ag1—O6	126.36 (5)	O6—Fe1—O5^vi	163.25 (5)
O6ⁱⁱ—Ag1—O6	53.64 (5)	O2—Fe1—O5^vi	101.04 (5)
O3ⁱ—Ag1—O6	84.51 (4)	O4^viii—Fe1—O5^vi	78.79 (5)
O3ⁱⁱ—Ag1—O6	95.49 (4)	O1ⁱ—Fe1—O5^vi	82.95 (5)
O3ⁱⁱⁱ—Ag1—O6	111.98 (4)	O6—Fe1—O1^ix	80.26 (5)
O3—Ag1—O6	68.02 (4)	O2—Fe1—O1^ix	171.95 (5)
O6ⁱⁱⁱ—Ag1—O6	180.0	O4^viii—Fe1—O1^ix	90.22 (4)
O2^iv—Ag2—O2	173.70 (6)	O1ⁱ—Fe1—O1^ix	84.52 (5)
O2^iv—Ag2—O2ⁱ	101.33 (4)	O5^vi—Fe1—O1^ix	85.66 (5)
O2—Ag2—O2ⁱ	78.34 (4)	O3^x—Fe2—O3^xi	80.97 (7)
O2^iv—Ag2—O2^v	78.34 (4)	O3^x—Fe2—O5^xii	91.27 (5)
O2—Ag2—O2^v	101.33 (4)	O3^xi—Fe2—O5^xii	112.81 (5)
O2ⁱ—Ag2—O2^v	174.04 (5)	O3^x—Fe2—O5^xiii	112.81 (5)
O2^iv—Ag2—O4	118.73 (4)	O3^xi—Fe2—O5^xiii	91.27 (5)
O2—Ag2—O4	55.50 (4)	O5^xii—Fe2—O5^xiii	148.74 (7)
O2ⁱ—Ag2—O4	61.33 (4)	O3^x—Fe2—O4^iv	85.08 (5)
O2^v—Ag2—O4	113.50 (4)	O3^xi—Fe2—O4^iv	164.39 (5)
O2^iv—Ag2—O4^iv	55.50 (4)	O5^xii—Fe2—O4^iv	74.29 (4)
O2—Ag2—O4^iv	118.73 (4)	O5^xiii—Fe2—O4^iv	87.71 (4)
O2ⁱ—Ag2—O4^iv	113.50 (4)	O3^x—Fe2—O4	164.39 (5)
O2^v—Ag2—O4^iv	61.33 (4)	O3^xi—Fe2—O4	85.08 (5)
O4—Ag2—O4^iv	77.51 (5)	O5^xii—Fe2—O4	87.71 (4)
O2^iv—Ag2—O5^vi	114.87 (4)	O5^xiii—Fe2—O4	74.29 (4)
O2—Ag2—O5^vi	71.23 (4)	O4^iv—Fe2—O4	109.56 (7)
O2ⁱ—Ag2—O5^vi	101.56 (4)	O3—P1—O2	112.57 (7)
O2^v—Ag2—O5^vi	83.86 (4)	O3—P1—O1	108.72 (7)
O4—Ag2—O5^vi	125.84 (3)	O2—P1—O1	109.47 (7)
O4^iv—Ag2—O5^vi	144.70 (3)	O3—P1—O4	109.98 (7)
O2^iv—Ag2—O5^vii	71.23 (4)	O2—P1—O4	107.31 (7)
O2—Ag2—O5^vii	114.87 (4)	O1—P1—O4	108.73 (7)
O2ⁱ—Ag2—O5^vii	83.86 (4)	O6ⁱⁱ—P2—O6	104.43 (10)
O2^v—Ag2—O5^vii	101.56 (4)	O6ⁱⁱ—P2—O5ⁱⁱ	108.75 (7)
O4—Ag2—O5^vii	144.70 (3)	O6—P2—O5ⁱⁱ	112.14 (7)
O4^iv—Ag2—O5^vii	125.84 (3)	O6ⁱⁱ—P2—O5	112.14 (7)
O5^vi—Ag2—O5^vii	52.03 (4)	O6—P2—O5	108.75 (7)
O2^iv—Ag2—O1ⁱ	119.96 (4)	O5ⁱⁱ—P2—O5	110.52 (9)

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

Acknowledgements

The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements.

Funding information

Funding for this research was provided by: Mohammed V University, Rabat, Morocco.

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