Synthesis and crystal structure of dipotassium nickel polyphosphate

Thiam, E.W.M.; Ba, K.M.; Kane, A.Y.; Thiam, I.E.; Claiser, N.; Souhassou, M.; Barry, A.H.; Gaye, M.

doi:10.1107/S2056989025002221

research communications

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 81| Part 4| April 2025| Pages 324-327

https://doi.org/10.1107/S2056989025002221

Open

access

Synthesis and crystal structure of dipotassium nickel polyphosphate

El Waleda Moustapha Thiam,^a Kalidou Mamadou Ba,^a Aichata Yaya Kane,^a Ibrahima Elhadji Thiam,^b ^* Nicolas Claiser,^c Mohamed Souhassou,^c Aliou Hamady Barry ^a and Mohamed Gaye ^b

^aUnité de Recherche en Chimie des Matériaux, Département de Chimie, Faculté des Sciences et Techniques, Université de Nouakchott, Mauritania, ^bDépartement de Chimie, Faculté des Sciences et Techniques, Université Cheik Anta Diop, Dakar, Senegal, and ^cCNRS, Laboratoire CRM2, UMR CNRS 7036, Université de Lorraine, boulevard des aiguillettes, BP 70239, Vandoeuvre-lès-Nancy, 54506, France
^*Correspondence e-mail:

Edited by S. P. Kelley, University of Missouri-Columbia, USA (Received 20 February 2025; accepted 11 March 2025; online 19 March 2025)

Single crystals of K₂Ni(PO₃)₄ were obtained by solid-state reaction. The structure consists of infinite zigzag polyphosphate chains, running along the c-axis direction, linked by Ni²⁺ ions and delimiting large tunnels in which the K⁺ ions are located. Ni²⁺ ions form slightly distorted NiO₆ octahedra and the coordination numbers of the independent potassium cations are 8 and 10.

Keywords: crystal structure; phosphate; potassium; nickel; octahedral; pentagonal.

CCDC reference: 2430654

1. Chemical context

Transition-metal oxides (Fe, Co, or Ni) in melted phosphate systems of alkali metals (M₂O–P₂O₅, M = Li, Na, or K) are widely studied (Pontchara & Durif, 1974 ; Litvin & Masloboev, 1989 ; Panahandeh & Jung, 2003 ; Moutataouia et al., 2014 ; Ouaatta et al., 2019 ). These materials present various and interesting properties and applications, such as catalysts (Moffat, 1978 ), ferroelectric and/or magnetic materials (Lazoryak et al., 2004 ; Hatert et al., 2004 ; Essehli et al., 2015 ) and ion-conduction properties (La Parola et al., 2018 ; Orikasa et al., 2016 ; Daidouh et al., 1999 ). Some of these specific properties, such as catalytic activity, are similar to those found in the phosphate systems themselves (Kapshuk et al., 2000 ). These compounds have been characterized by several physico-chemical and structural methods. Among these studies, some have been devoted to nickel-based phosphates associated with alkali metals, such as the polyphosphates MNi(PO₃)₃ (M = Li, Na, or K; Kapshuk et al., 2000) and NiCs₄(PO₃)₆ (Sbai et al., 2004 ). For all these samples, the study of their structural characteristics is essential for understanding most of the physical properties (Fischer et al., 1994 ). The title polyphosphate, K₂Ni(PO₃)₄, designated as (1), was obtained in the quest to synthesize new condensed phosphates appearing in the A₂O–MO–LnO₃–P₂O₅ quaternary system (A: an alkali metal, M: transition metal divalent cation, Ln: lanthanide or Y metal). This compound has been observed in the diagram Ni(PO₃)₂–KPO₃ (Pontchara & Durif, 1974) but, to our knowledge, its crystal structure has not yet been reported. We report herein on its synthesis and structural characterization by single crystal X-ray diffraction.

2. Structural commentary

The title compound, (1), crystallizes in the non-centrosymmetric monoclinic space group Cc. The asymmetric unit contains 19 atoms corresponding to the chemical formula K₂Ni(PO₃)₄, as shown in Fig. 1. The structure is based on infinite zigzag polyphosphate chains running almost along the c-axis direction and linked by NiO₆ octahedra (Fig. 2). Each NiO₆ octahedron shares corners with six different PO₄ tetrahedra belonging to three polyphosphate chains. All the terminal O atoms of the PO₄ tetrahedra in the polyphosphate chains interact with the Ni and K atoms. Such an arrangement creates a three-dimensional framework that delimits large hexagonal and pentagonal tunnels in which the K⁺ ions are located (Fig. 3). The NiO₆ octahedra are slightly distorted, with Ni—O distances ranging from 2.017 (2) to 2.167 (2) Å and the O—Ni—O angles from 82.52 (6)° to 173.51 (6)°. In the four PO₄ tetrahedra, the equatorial and apical distances P—OE and P—OL, respectively, range from 1.469 (2) to 1.493 (2) Å for P—OE and 1.578 (1) to 1.602 (1)Å for P—OL and the O—P—O angles range from 100.37 (10) to 120.76 (10)°. The unit cell contains two crystallographically non-equivalent K atoms (K1 and K2) both located in large hexagonal and pentagonal tunnels (Fig. 3). The coordination number (CN) is 8 for K1 and 10 for K2. The K—O interactions range from 2.582 (2) and 3.111 (2) Å for K1 (mean distance: 2.841 Å) and 2.761 (2) to 3.414 (2) Å for K2 (mean distance: 3.041 Å)

Figure 1
The asymmetric unit of K₂Ni(PO₃)₄.

Figure 2
Projection of the K₂Ni(PO₃)₄ structure along [100].

Figure 3
Polyhedral representation of the structure of K₂Ni(PO₃)₄ showing the tunnels in which the K⁺ cations are located.

3. Database survey

A search in the Cambridge Structural Database (Version 5.43, November 2021; Groom et al., 2016 ) revealed about a dozen alkaline nickel-based phosphates: TlNi₄(PO₄)₃, Tl₄Ni₇(PO₄)₆ and Tl₂Ni₄(P₂O₇)(PO₄)₂ (Panahandeh & Jung, 2003), KNi₃(PO₄)P₂O₇ (Moutataouia et al., 2014), K₂Ni₄(PO₄)₂(P₂O₇) (Palkina et al., 1980 ), K₂NiP₂O₇ (El Maadi et al., 1995 ), AM₄(PO₄)₃ (A = Na, K, Rb; M = Ni, Mn) (Daidouh et al., 1999), MNi(PO₃)₃ (M = Na or K) (Kapshuk et al., 2000), KNiPO₄ (Fischer et al., 1994), NiCs₄(PO₃)₆ and NiK₄(P₃O₉)₂ (Sbai et al., 2004). As in the case of the title compound, the structures of MNi(PO₃)₃ (M = Na or K) polyphosphates are based on infinite zigzag polyphosphate chains, linked by Ni²⁺ ions in octahedral coordination and delimiting tunnels in which the alkali ions are located (Fig. 3). The metal atoms (M) and nickel atoms form infinite ⋯Ni–M–Ni–M⋯ columns of polyhedra sharing edges and alternating with the polyphosphate chains. In the NaNi(PO₃)₃ structure (Kapshuk et al., 2000), the polyphosphate chains run along the a-axis direction, and the Na atom exhibits a distorted octahedral environment whereas in KNi(PO₃)₃, the polyphosphate chains are run in the same direction as in the title polyphosphate (c-axis) and the coordination polyhedron of the K atom is a distorted tricapped trigonal prism (CN = 9), unlike in the title polyphosphate where the K atoms exhibit two different coordination numbers (8 and 10). In the other alkaline nickel-based phosphates TlNi₄(PO₄)₃, Tl₄Ni₇(PO₄)₆, Tl₂Ni₄(P₂O₇)(PO₄)₂, KNi₃(PO₄)P₂O₇, K₂Ni₄(PO₄)₂(P₂O₇), K₂NiP₂O₇, AM₄(PO₄)₃ (A = Na, K, Rb; M = Ni, Mn); the structural arrangements are markedly different from that of the title compound being based on alkali and Ni polyhedra sharing edges and forming chains that are linked together by isolated PO₄ and/or diphosphate (P₂O₇) groups. In addition, the coordination polyhedron of the Ni atom is not always octahedral. For instance, it is 7-coordinated in TlNi₄(PO₄)₃, 5-coordinated in KNi₄(PO₄)₃ and has an unusual coordination of only four oxygen atoms in a distorted tetrahedron in Tl₂Ni₄(P₂O₇)(PO₄)₂. The coordination numbers of the metal atoms (Tl and K) in these phosphates range from 6 to 12. Thallium nickel phosphate, Tl₂Ni₄(P₂O₇)(PO₄)₂, adopts the K₂Ni₄(PO₄)₂(P₂O₇) structure, and the environments of the alkali and nickel atoms are nearly identical.

4. Synthesis and crystallization

Single crystals of K₂Ni(PO₃)₄ were prepared by solid-state reaction. A mixture of the reagents K₂CO₃, NiCl₂·6H₂O, NH₄H₂PO₄ and La₂O₃ in a molar ratio of K:Ni:P:La of 0.4:0.05:1:0.02 was placed in a porcelain crucible. The reaction mixture was then calcined at 623 K for 1 h and gradually heated to 823 K. Maintained at this temperature for 72 h, the reaction mixture then underwent slow cooling at a rate of 1 K h⁻¹ to 773 K and then to room temperature with furnace inertia. The crystals obtained were recovered after washing with boiling water.

5. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. Solving and refinement tests of the structure were carried out in both the centrosymmetric and non-centrosymmetric space groups C2/c and Cc. Better results with a much convergent refinement were obtained with the non-centrosymmetric model. The use of the TWIN refinement mode made the refinement results significantly improved. No Extinction correction was applied. The residual maximum and minimum electron density peaks are located 0.13 Å from P1 and 0.36 Å from Ni1, respectively. However, the minimum density observed in the vicinity of a nickel atom is rather largely negative (−2.6 e Å⁻³) indicating probably that the absorption correction applied was not optimal.

Table 1
Experimental details

Crystal data
Chemical formula	K₂Ni(PO₃)₄
M_r	452.79
Crystal system, space group	Monoclinic, Cc
Temperature (K)	293
a, b, c (Å)	11.07179 (16), 12.50386 (16), 7.53969 (11)
β (°)	103.2349 (14)
V (Å³)	1016.07 (3)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	3.43
Crystal size (mm)	0.12 × 0.08 × 0.07

Data collection
Diffractometer	SuperNova
Absorption correction	Multi-scan (CrysAlis PRO; Rigaku OD, 2022 $[Rigaku OD (2022). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England.]$ )
T_min, T_max	0.509, 0.710
No. of measured, independent and observed [I > 2σ(I)] reflections	33158, 8076, 7869
R_int	0.035
(sin θ/λ)_max (Å⁻¹)	0.999

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.031, 0.088, 1.07
No. of reflections	8076
No. of parameters	173
No. of restraints	2
Δρ_max, Δρ_min (e Å⁻³)	0.83, −2.85
Absolute structure	Refined as an inversion twin
Absolute structure parameter	0.539 (9)
Computer programs: CrysAlis PRO (Rigaku OD, 2022 $[Rigaku OD (2022). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England.]$ ), SHELXT (Sheldrick, 2015a ), SHELXL (Sheldrick, 2015b ), ORTEP-3 for Windows (Farrugia, 2012 ), DIAMOND (Brandenburg, 2006 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 2430654

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989025002221/ev2014sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989025002221/ev2014Isup2.hkl

checkCIF report

Computing details top

Dipotassium nickel polyphosphate top

Crystal data top

K₂Ni(PO₃)₄	F(000) = 888
M_r = 452.79	D_x = 2.960 Mg m⁻³
Monoclinic, Cc	Mo Kα radiation, λ = 0.71073 Å
a = 11.07179 (16) Å	Cell parameters from 5641 reflections
b = 12.50386 (16) Å	θ = 2.5–45.2°
c = 7.53969 (11) Å	µ = 3.43 mm⁻¹
β = 103.2349 (14)°	T = 293 K
V = 1016.07 (3) Å³	Block, metallic reddish red
Z = 4	0.12 × 0.08 × 0.07 mm

Data collection top

SuperNova diffractometer	R_int = 0.035
θ/2θ scans	θ_max = 45.2°, θ_min = 2.5°
Absorption correction: multi-scan (CrysAlisPro; Rigaku OD, 2022)	h = −22→21
T_min = 0.509, T_max = 0.710	k = −24→24
33158 measured reflections	l = −14→14
8076 independent reflections	3 standard reflections every 120 min
7869 reflections with I > 2σ(I)	intensity decay: none

Refinement top

Refinement on F²	2 restraints
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.0564P)² + 1.2215P] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.031	(Δ/σ)_max = 0.001
wR(F²) = 0.088	Δρ_max = 0.83 e Å⁻³
S = 1.07	Δρ_min = −2.85 e Å⁻³
8076 reflections	Absolute structure: Refined as an inversion twin
173 parameters	Absolute structure parameter: 0.539 (9)

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.

Refinement. Refined as a 2-component inversion twin.

Data were collected on a SuperNova diffractometer equipped with a (Mo)X-ray Source and an Atlas CCD detector. Cell refinement and data reduction were performed with CrysAlisPro 1.171.42.49 (Rigaku, 2022) and adsorption correction withSCALE3 ABSPACK scaling algorithm (Rigaku Oxford Diffraction, 2022). Using the SHELX software package, the structure was solved by the direct method with the SHELXS program (Sheldrick, 2015a) and refined by the full-matrix least-squares method using SHELXL program (Sheldrick, 2015b). The programs Ortep-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg, 2006) were used for molecular graphics and the software publCIF (Westrip, 2010) to prepare material for publication.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Ni1	0.94642 (3)	0.34669 (2)	0.79387 (4)	0.00586 (5)
K1	0.61359 (4)	0.63341 (3)	0.12530 (6)	0.00747 (6)
K2	1.31600 (5)	0.37393 (4)	0.96892 (7)	0.01014 (7)
P1	1.05470 (5)	0.57511 (4)	0.70758 (7)	0.00330 (7)
P2	0.83590 (5)	0.57688 (4)	0.86578 (7)	0.00340 (7)
P3	0.62807 (5)	0.68963 (4)	0.62381 (7)	0.00407 (7)
P4	1.28454 (5)	0.66069 (4)	0.97345 (7)	0.00384 (7)
O1	0.94041 (16)	0.62429 (12)	0.7749 (2)	0.0065 (2)
O2	0.84766 (14)	0.45926 (12)	0.8902 (2)	0.00540 (19)
O3	0.71177 (15)	0.58966 (12)	0.7095 (2)	0.0066 (2)
O4	1.16650 (16)	0.59314 (15)	0.8769 (2)	0.0088 (2)
O5	1.04508 (15)	0.45704 (12)	0.6879 (2)	0.0058 (2)
O6	0.82806 (16)	0.64783 (12)	1.0220 (2)	0.0059 (2)
O7	1.07218 (15)	0.64267 (13)	0.5525 (2)	0.0059 (2)
O8	1.31674 (15)	0.73723 (13)	0.8407 (2)	0.0074 (2)
O9	1.23326 (16)	0.72198 (13)	1.1278 (2)	0.0070 (2)
O10	1.37679 (15)	0.58280 (13)	1.0701 (2)	0.0085 (2)
O11	0.55585 (16)	0.72302 (13)	0.7586 (2)	0.0076 (2)
O12	0.56100 (16)	0.66049 (14)	0.4387 (2)	0.0085 (2)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ni1	0.00581 (9)	0.00526 (8)	0.00660 (8)	0.00012 (7)	0.00160 (7)	0.00007 (7)
K1	0.00615 (13)	0.00922 (13)	0.00764 (13)	−0.00002 (12)	0.00283 (10)	−0.00036 (12)
K2	0.00994 (16)	0.00745 (14)	0.01295 (17)	−0.00041 (12)	0.00245 (13)	−0.00230 (12)
P1	0.00303 (16)	0.00325 (16)	0.00364 (15)	−0.00080 (12)	0.00081 (12)	−0.00030 (12)
P2	0.00332 (16)	0.00287 (15)	0.00425 (15)	0.00051 (12)	0.00139 (12)	−0.00014 (12)
P3	0.00380 (16)	0.00497 (16)	0.00343 (15)	0.00063 (12)	0.00079 (12)	0.00020 (13)
P4	0.00303 (16)	0.00393 (17)	0.00437 (16)	−0.00011 (12)	0.00048 (13)	−0.00040 (12)
O1	0.0059 (5)	0.0051 (4)	0.0101 (6)	0.0000 (4)	0.0052 (4)	0.0001 (4)
O2	0.0059 (5)	0.0030 (4)	0.0075 (5)	0.0009 (3)	0.0020 (4)	0.0005 (3)
O3	0.0050 (5)	0.0051 (4)	0.0085 (5)	0.0007 (4)	−0.0008 (4)	0.0003 (4)
O4	0.0073 (5)	0.0110 (6)	0.0063 (5)	−0.0048 (4)	−0.0023 (4)	0.0003 (4)
O5	0.0065 (5)	0.0037 (4)	0.0076 (5)	−0.0006 (4)	0.0026 (4)	−0.0007 (4)
O6	0.0069 (5)	0.0053 (5)	0.0057 (5)	0.0009 (4)	0.0019 (4)	−0.0014 (4)
O7	0.0065 (5)	0.0067 (5)	0.0048 (5)	−0.0015 (4)	0.0017 (4)	0.0008 (4)
O8	0.0073 (5)	0.0075 (5)	0.0082 (5)	−0.0011 (4)	0.0035 (4)	0.0013 (4)
O9	0.0087 (5)	0.0064 (5)	0.0064 (5)	0.0020 (4)	0.0029 (4)	−0.0011 (4)
O10	0.0060 (5)	0.0068 (5)	0.0112 (6)	0.0023 (4)	−0.0007 (4)	0.0016 (4)
O11	0.0085 (5)	0.0078 (5)	0.0078 (5)	0.0023 (4)	0.0043 (4)	0.0005 (4)
O12	0.0074 (5)	0.0129 (6)	0.0044 (5)	−0.0006 (4)	−0.0004 (4)	−0.0008 (4)

Geometric parameters (Å, º) top

Ni1—K1ⁱ	3.6212 (6)	K2—O6^vi	2.8540 (16)
Ni1—K1ⁱⁱ	3.8294 (5)	K2—O7ⁱ	2.9168 (18)
Ni1—K2ⁱⁱⁱ	3.7520 (6)	K2—O8ⁱ	3.1274 (18)
Ni1—K2	4.0161 (6)	K2—O9^iv	2.7951 (17)
Ni1—O2	2.0168 (15)	K2—O10^iv	3.273 (2)
Ni1—O5	2.0335 (16)	K2—O10	2.7605 (18)
Ni1—O6^iv	2.1666 (16)	K2—O11^x	3.2612 (18)
Ni1—O7ⁱ	2.1253 (16)	K2—O12^x	2.8069 (19)
Ni1—O8^v	2.0717 (16)	P1—O1	1.5910 (17)
Ni1—O11^vi	2.0194 (16)	P1—O4	1.5779 (16)
K1—P2^vii	3.5486 (7)	P1—O5	1.4852 (16)
K1—P2^iv	3.7705 (7)	P1—O7	1.4903 (16)
K1—P4^viii	3.5763 (7)	P2—O1	1.5882 (17)
K1—O2^iv	3.1108 (16)	P2—O2	1.4842 (16)
K1—O3^iv	3.0080 (16)	P2—O3	1.6002 (16)
K1—O6^vii	2.6693 (18)	P2—O6	1.4928 (16)
K1—O7^ix	2.8697 (16)	P3—O3	1.6016 (16)
K1—O8^ix	2.9396 (17)	P3—O9^ix	1.6009 (17)
K1—O10^viii	2.6358 (18)	P3—O11	1.4893 (17)
K1—O11^vii	2.9154 (17)	P3—O12	1.4691 (17)
K1—O12	2.5817 (18)	P4—O4	1.5860 (17)
K2—P3^x	3.4765 (7)	P4—O8	1.4858 (17)
K2—P4	3.6034 (7)	P4—O9	1.6022 (17)
K2—O4	3.195 (2)	P4—O10	1.4771 (16)
K2—O5	3.4141 (17)

K1ⁱ—Ni1—K1ⁱⁱ	125.300 (12)	O10—K2—O5	90.43 (4)
K1ⁱ—Ni1—K2ⁱⁱⁱ	67.218 (12)	O10—K2—O6^vi	153.87 (5)
K1ⁱⁱ—Ni1—K2	62.662 (11)	O10—K2—O7ⁱ	100.77 (5)
K1ⁱ—Ni1—K2	171.099 (12)	O10—K2—O8ⁱ	102.85 (5)
K2ⁱⁱⁱ—Ni1—K1ⁱⁱ	88.300 (11)	O10—K2—O9^iv	131.91 (5)
K2ⁱⁱⁱ—Ni1—K2	119.195 (13)	O10—K2—O10^iv	90.52 (4)
O2—Ni1—K1ⁱⁱ	118.16 (5)	O10—K2—O11^x	93.26 (5)
O2—Ni1—K1ⁱ	59.09 (5)	O10—K2—O12^x	89.34 (5)
O2—Ni1—K2ⁱⁱⁱ	126.08 (5)	O11^x—K2—P3^x	25.28 (3)
O2—Ni1—K2	114.71 (5)	O11^x—K2—P4	115.41 (3)
O2—Ni1—O5	92.99 (6)	O11^x—K2—O5	173.59 (4)
O2—Ni1—O6^iv	93.34 (6)	O11^x—K2—O10^iv	111.68 (4)
O2—Ni1—O7ⁱ	85.48 (6)	O12^x—K2—P3^x	24.16 (3)
O2—Ni1—O8^v	86.88 (7)	O12^x—K2—P4	104.51 (4)
O2—Ni1—O11^vi	166.65 (7)	O12^x—K2—O4	125.18 (5)
O5—Ni1—K1ⁱⁱ	120.40 (5)	O12^x—K2—O5	136.41 (5)
O5—Ni1—K1ⁱ	114.24 (5)	O12^x—K2—O6^vi	81.05 (5)
O5—Ni1—K2	58.20 (5)	O12^x—K2—O7ⁱ	165.05 (5)
O5—Ni1—K2ⁱⁱⁱ	113.79 (5)	O12^x—K2—O8ⁱ	101.57 (5)
O5—Ni1—O6^iv	82.52 (6)	O12^x—K2—O10^iv	62.93 (5)
O5—Ni1—O7ⁱ	91.15 (6)	O12^x—K2—O11^x	48.97 (4)
O5—Ni1—O8^v	166.15 (7)	K1^xi—P1—K2^iv	65.244 (13)
O6^iv—Ni1—K1ⁱ	47.10 (5)	O1—P1—K1^xi	81.92 (6)
O6^iv—Ni1—K1ⁱⁱ	137.45 (4)	O1—P1—K2^iv	146.61 (6)
O6^iv—Ni1—K2	131.17 (5)	O4—P1—K1^xi	82.08 (7)
O6^iv—Ni1—K2ⁱⁱⁱ	49.19 (4)	O4—P1—K2^iv	79.50 (7)
O7ⁱ—Ni1—K1ⁱⁱ	47.74 (4)	O4—P1—O1	102.73 (10)
O7ⁱ—Ni1—K1ⁱ	135.89 (5)	O5—P1—K1^xi	162.46 (7)
O7ⁱ—Ni1—K2ⁱⁱⁱ	135.94 (4)	O5—P1—K2^iv	99.47 (7)
O7ⁱ—Ni1—K2	44.68 (5)	O5—P1—O1	111.84 (9)
O7ⁱ—Ni1—O6^iv	173.50 (6)	O5—P1—O4	104.35 (10)
O8^v—Ni1—K1ⁱ	54.26 (5)	O5—P1—O7	120.29 (9)
O8^v—Ni1—K1ⁱⁱ	71.27 (5)	O7—P1—K1^xi	42.80 (6)
O8^v—Ni1—K2ⁱⁱⁱ	56.46 (5)	O7—P1—K2^iv	44.18 (7)
O8^v—Ni1—K2	133.93 (5)	O7—P1—O1	106.67 (9)
O8^v—Ni1—O6^iv	83.66 (6)	O7—P1—O4	109.57 (10)
O8^v—Ni1—O7ⁱ	102.64 (7)	K1^xii—P2—K1ⁱ	86.856 (17)
O11^vi—Ni1—K1ⁱⁱ	48.53 (5)	K1^xii—P2—K2^xiii	67.271 (14)
O11^vi—Ni1—K1ⁱ	126.83 (5)	K1ⁱ—P2—K2^xiii	135.710 (18)
O11^vi—Ni1—K2ⁱⁱⁱ	60.25 (5)	O1—P2—K1^xii	146.03 (6)
O11^vi—Ni1—K2	60.75 (5)	O1—P2—K1ⁱ	120.85 (7)
O11^vi—Ni1—O5	94.32 (7)	O1—P2—K2^xiii	78.82 (6)
O11^vi—Ni1—O6^iv	98.67 (7)	O1—P2—O3	103.48 (9)
O11^vi—Ni1—O7ⁱ	83.22 (7)	O2—P2—K1^xii	100.44 (7)
O11^vi—Ni1—O8^v	88.67 (7)	O2—P2—K1ⁱ	52.96 (6)
Ni1^iv—K1—P2^iv	51.633 (11)	O2—P2—K2^xiii	161.42 (7)
P2^vii—K1—Ni1^iv	55.151 (12)	O2—P2—O1	111.80 (9)
P2^vii—K1—P2^iv	70.573 (13)	O2—P2—O3	103.08 (9)
P2^vii—K1—P4^viii	128.817 (18)	O2—P2—O6	120.69 (9)
P4^viii—K1—Ni1^iv	170.418 (17)	O3—P2—K1ⁱ	50.17 (6)
P4^viii—K1—P2^iv	136.511 (17)	O3—P2—K1^xii	78.39 (7)
O2^iv—K1—Ni1^iv	33.80 (3)	O3—P2—K2^xiii	88.45 (6)
O2^iv—K1—P2^iv	22.39 (3)	O6—P2—K1ⁱ	130.12 (7)
O2^iv—K1—P2^vii	72.46 (3)	O6—P2—K1^xii	43.42 (7)
O2^iv—K1—P4^viii	151.52 (3)	O6—P2—K2^xiii	40.83 (6)
O3^iv—K1—Ni1^iv	72.55 (3)	O6—P2—O1	107.34 (9)
O3^iv—K1—P2^vii	70.67 (4)	O6—P2—O3	109.04 (9)
O3^iv—K1—P2^iv	24.11 (3)	K2^xiii—P3—K1	134.104 (18)
O3^iv—K1—P4^viii	116.65 (3)	K2^xiv—P3—K1	79.126 (15)
O3^iv—K1—O2^iv	46.48 (4)	K2^xiv—P3—K2^xiii	136.71 (2)
O6^vii—K1—Ni1^iv	36.48 (4)	O3—P3—K1	98.32 (7)
O6^vii—K1—P2^iv	70.19 (4)	O3—P3—K2^xiv	113.32 (6)
O6^vii—K1—P2^vii	22.61 (3)	O3—P3—K2^xiii	91.25 (6)
O6^vii—K1—P4^viii	144.02 (4)	O9^ix—P3—K1	90.70 (6)
O6^vii—K1—O2^iv	63.03 (5)	O9^ix—P3—K2^xiii	43.41 (6)
O6^vii—K1—O3^iv	79.73 (5)	O9^ix—P3—K2^xiv	145.79 (6)
O6^vii—K1—O7^ix	89.55 (5)	O9^ix—P3—O3	100.37 (9)
O6^vii—K1—O8^ix	60.32 (5)	O11—P3—K1	145.19 (7)
O6^vii—K1—O11^vii	73.37 (5)	O11—P3—K2^xiii	69.63 (7)
O7^ix—K1—Ni1^iv	96.04 (4)	O11—P3—K2^xiv	69.25 (7)
O7^ix—K1—P2^iv	146.15 (4)	O11—P3—O3	107.15 (10)
O7^ix—K1—P2^vii	100.93 (4)	O11—P3—O9^ix	107.19 (10)
O7^ix—K1—P4^viii	74.89 (4)	O12—P3—K1	27.68 (7)
O7^ix—K1—O2^iv	124.00 (4)	O12—P3—K2^xiv	51.45 (8)
O7^ix—K1—O3^iv	168.30 (5)	O12—P3—K2^xiii	153.56 (7)
O7^ix—K1—O8^ix	68.73 (5)	O12—P3—O3	108.05 (9)
O7^ix—K1—O11^vii	56.84 (5)	O12—P3—O9^ix	113.35 (10)
O8^ix—K1—Ni1^iv	34.89 (3)	O12—P3—O11	118.97 (11)
O8^ix—K1—P2^iv	77.60 (3)	K1^xv—P4—K1^xi	126.000 (18)
O8^ix—K1—P2^vii	82.80 (3)	K1^xv—P4—K2ⁱ	79.159 (15)
O8^ix—K1—P4^viii	135.97 (4)	K1^xv—P4—K2	79.311 (16)
O8^ix—K1—O2^iv	55.29 (4)	K2—P4—K1^xi	133.819 (19)
O8^ix—K1—O3^iv	101.52 (5)	K2ⁱ—P4—K1^xi	133.235 (18)
O10^viii—K1—Ni1^iv	165.34 (4)	K2—P4—K2ⁱ	84.614 (14)
O10^viii—K1—P2^iv	115.13 (4)	O4—P4—K1^xi	79.54 (7)
O10^viii—K1—P2^vii	130.96 (4)	O4—P4—K1^xv	140.19 (8)
O10^viii—K1—P4^viii	21.38 (4)	O4—P4—K2	62.42 (7)
O10^viii—K1—O2^iv	131.63 (5)	O4—P4—K2ⁱ	106.16 (7)
O10^viii—K1—O3^iv	96.26 (5)	O4—P4—O9	101.31 (10)
O10^viii—K1—O6^vii	152.78 (6)	O8—P4—K1^xi	42.82 (7)
O10^viii—K1—O7^ix	95.42 (5)	O8—P4—K1^xv	83.87 (7)
O10^viii—K1—O8^ix	145.79 (5)	O8—P4—K2	126.58 (7)
O10^viii—K1—O11^vii	87.03 (5)	O8—P4—K2ⁱ	140.74 (7)
O11^vii—K1—Ni1^iv	106.92 (4)	O8—P4—O4	109.49 (10)
O11^vii—K1—P2^iv	134.53 (4)	O8—P4—O9	111.14 (9)
O11^vii—K1—P2^vii	65.34 (3)	O9—P4—K1^xi	88.55 (6)
O11^vii—K1—P4^viii	70.95 (4)	O9—P4—K1^xv	108.51 (6)
O11^vii—K1—O2^iv	136.18 (5)	O9—P4—K2ⁱ	44.69 (6)
O11^vii—K1—O3^iv	123.15 (5)	O9—P4—K2	122.27 (6)
O11^vii—K1—O8^ix	106.65 (5)	O10—P4—K1^xv	40.58 (7)
O12—K1—Ni1^iv	95.42 (4)	O10—P4—K1^xi	162.48 (8)
O12—K1—P2^vii	149.42 (4)	O10—P4—K2ⁱ	61.96 (8)
O12—K1—P2^iv	84.87 (4)	O10—P4—K2	44.86 (7)
O12—K1—P4^viii	81.60 (4)	O10—P4—O4	106.22 (10)
O12—K1—O2^iv	77.92 (5)	O10—P4—O8	120.76 (10)
O12—K1—O3^iv	94.28 (5)	O10—P4—O9	106.09 (10)
O12—K1—O6^vii	131.32 (5)	P2—O1—P1	134.80 (10)
O12—K1—O7^ix	89.27 (5)	Ni1—O2—K1ⁱ	87.11 (5)
O12—K1—O8^ix	74.13 (5)	P2—O2—Ni1	133.34 (10)
O12—K1—O10^viii	75.61 (6)	P2—O2—K1ⁱ	104.66 (7)
O12—K1—O11^vii	140.45 (5)	P2—O3—K1ⁱ	105.71 (7)
P3^x—K2—P4	108.365 (18)	P2—O3—P3	134.04 (11)
O4—K2—P3^x	134.00 (3)	P3—O3—K1ⁱ	119.39 (8)
O4—K2—P4	26.10 (3)	P1—O4—K2	108.94 (9)
O4—K2—O5	42.80 (4)	P1—O4—P4	149.18 (13)
O4—K2—O10^iv	82.19 (5)	P4—O4—K2	91.47 (8)
O4—K2—O11^x	140.01 (4)	Ni1—O5—K2	91.39 (5)
O5—K2—P3^x	160.47 (3)	P1—O5—Ni1	131.91 (10)
O5—K2—P4	68.28 (3)	P1—O5—K2	102.00 (7)
O6^vi—K2—P3^x	73.47 (4)	Ni1ⁱ—O6—K1^xii	96.42 (6)
O6^vi—K2—P4	170.35 (4)	Ni1ⁱ—O6—K2^xiii	95.74 (5)
O6^vi—K2—O4	152.31 (5)	K1^xii—O6—K2^xiii	95.26 (5)
O6^vi—K2—O5	113.25 (4)	P2—O6—Ni1ⁱ	129.30 (10)
O6^vi—K2—O7ⁱ	85.13 (5)	P2—O6—K1^xii	113.98 (9)
O6^vi—K2—O8ⁱ	56.20 (5)	P2—O6—K2^xiii	119.17 (9)
O6^vi—K2—O10^iv	106.24 (5)	Ni1^iv—O7—K1^xi	99.02 (6)
O6^vi—K2—O11^x	62.17 (5)	Ni1^iv—O7—K2^iv	104.50 (6)
O7ⁱ—K2—P3^x	143.99 (4)	K1^xi—O7—K2^iv	89.74 (5)
O7ⁱ—K2—P4	88.43 (3)	P1—O7—Ni1^iv	125.44 (10)
O7ⁱ—K2—O4	69.44 (5)	P1—O7—K1^xi	116.54 (8)
O7ⁱ—K2—O5	55.30 (4)	P1—O7—K2^iv	114.96 (9)
O7ⁱ—K2—O8ⁱ	65.62 (5)	Ni1^xvi—O8—K1^xi	90.84 (6)
O7ⁱ—K2—O10^iv	127.26 (5)	Ni1^xvi—O8—K2^iv	90.02 (6)
O7ⁱ—K2—O11^x	118.74 (5)	K1^xi—O8—K2^iv	84.52 (4)
O8ⁱ—K2—P3^x	78.40 (3)	P4—O8—Ni1^xvi	145.38 (11)
O8ⁱ—K2—P4	114.47 (3)	P4—O8—K1^xi	117.09 (9)
O8ⁱ—K2—O4	118.08 (5)	P4—O8—K2^iv	111.44 (8)
O8ⁱ—K2—O5	120.88 (4)	P3^xi—O9—K2ⁱ	113.41 (8)
O8ⁱ—K2—O10^iv	159.73 (5)	P3^xi—O9—P4	133.93 (11)
O8ⁱ—K2—O11^x	53.12 (4)	P4—O9—K2ⁱ	111.54 (8)
O9^iv—K2—P3^x	107.59 (4)	K1^xv—O10—K2	116.20 (6)
O9^iv—K2—P4	115.06 (4)	K1^xv—O10—K2ⁱ	102.79 (5)
O9^iv—K2—O4	97.12 (5)	K2—O10—K2ⁱ	108.77 (6)
O9^iv—K2—O5	60.22 (4)	P4—O10—K1^xv	118.04 (9)
O9^iv—K2—O6^vi	72.48 (5)	P4—O10—K2ⁱ	94.57 (8)
O9^iv—K2—O7ⁱ	92.51 (5)	P4—O10—K2	112.97 (9)
O9^iv—K2—O8ⁱ	124.55 (5)	Ni1^xiii—O11—K1^xii	100.21 (6)
O9^iv—K2—O10^iv	47.05 (4)	Ni1^xiii—O11—K2^xiv	87.23 (6)
O9^iv—K2—O11^x	120.12 (5)	K1^xii—O11—K2^xiv	117.41 (6)
O9^iv—K2—O12^x	88.78 (5)	P3—O11—Ni1^xiii	137.44 (11)
O10^iv—K2—P3^x	87.07 (3)	P3—O11—K1^xii	120.26 (9)
O10—K2—P3^x	87.87 (4)	P3—O11—K2^xiv	85.46 (7)
O10^iv—K2—P4	83.39 (3)	K1—O12—K2^xiv	118.61 (6)
O10—K2—P4	22.17 (3)	P3—O12—K1	136.99 (11)
O10—K2—O4	47.91 (4)	P3—O12—K2^xiv	104.38 (9)
O10^iv—K2—O5	73.49 (4)

K1^xi—P1—O1—P2	−175.17 (16)	O1—P2—O2—Ni1	−12.87 (16)
K1^xi—P1—O4—K2	−149.54 (7)	O1—P2—O2—K1ⁱ	−112.96 (8)
K1^xi—P1—O4—P4	−20.6 (3)	O1—P2—O3—K1ⁱ	119.13 (8)
K1^xi—P1—O5—Ni1	−159.81 (12)	O1—P2—O3—P3	−72.00 (17)
K1^xi—P1—O5—K2	97.2 (2)	O1—P2—O6—Ni1ⁱ	−79.45 (13)
K1^xi—P1—O7—Ni1^iv	−124.79 (16)	O1—P2—O6—K1^xii	159.07 (8)
K1^xi—P1—O7—K2^iv	103.12 (10)	O1—P2—O6—K2^xiii	47.77 (11)
K1ⁱ—P2—O1—P1	−59.95 (18)	O2—P2—O1—P1	−1.07 (19)
K1^xii—P2—O1—P1	159.50 (8)	O2—P2—O3—K1ⁱ	2.53 (10)
K1^xii—P2—O2—Ni1	178.03 (11)	O2—P2—O3—P3	171.40 (15)
K1ⁱ—P2—O2—Ni1	100.09 (14)	O2—P2—O6—Ni1ⁱ	50.18 (16)
K1^xii—P2—O2—K1ⁱ	77.94 (5)	O2—P2—O6—K1^xii	−71.30 (12)
K1^xii—P2—O3—K1ⁱ	−95.65 (6)	O2—P2—O6—K2^xiii	177.41 (8)
K1ⁱ—P2—O3—P3	168.9 (2)	O3—P2—O1—P1	−111.34 (16)
K1^xii—P2—O3—P3	73.22 (15)	O3—P2—O2—Ni1	97.66 (13)
K1^xii—P2—O6—Ni1ⁱ	121.48 (15)	O3—P2—O2—K1ⁱ	−2.43 (10)
K1ⁱ—P2—O6—Ni1ⁱ	115.61 (10)	O3—P2—O6—Ni1ⁱ	169.07 (11)
K1ⁱ—P2—O6—K1^xii	−5.87 (12)	O3—P2—O6—K1^xii	47.60 (11)
K1^xii—P2—O6—K2^xiii	−111.29 (12)	O3—P2—O6—K2^xiii	−63.70 (11)
K1ⁱ—P2—O6—K2^xiii	−117.17 (7)	O3—P3—O11—Ni1^xiii	170.05 (14)
K1—P3—O3—K1ⁱ	−63.59 (8)	O3—P3—O11—K1^xii	10.20 (12)
K1—P3—O3—P2	128.73 (15)	O3—P3—O11—K2^xiv	−109.04 (7)
K1—P3—O11—Ni1^xiii	−54.8 (2)	O3—P3—O12—K1	−72.92 (16)
K1—P3—O11—K1^xii	145.33 (7)	O3—P3—O12—K2^xiv	105.83 (9)
K1—P3—O11—K2^xiv	26.10 (12)	O4—P1—O1—P2	−95.24 (17)
K1—P3—O12—K2^xiv	178.75 (19)	O4—P1—O5—Ni1	90.47 (14)
K1^xi—P4—O4—K2	152.97 (5)	O4—P1—O5—K2	−12.48 (10)
K1^xv—P4—O4—K2	17.57 (12)	O4—P1—O7—Ni1^iv	−177.97 (11)
K1^xv—P4—O4—P1	−115.0 (2)	O4—P1—O7—K1^xi	−53.18 (12)
K1^xi—P4—O4—P1	20.4 (3)	O4—P1—O7—K2^iv	49.94 (12)
K1^xi—P4—O8—Ni1^xvi	140.4 (2)	O4—P4—O8—Ni1^xvi	−171.34 (17)
K1^xv—P4—O8—Ni1^xvi	−29.95 (18)	O4—P4—O8—K1^xi	48.30 (12)
K1^xv—P4—O8—K1^xi	−170.31 (8)	O4—P4—O8—K2^iv	−46.62 (12)
K1^xi—P4—O8—K2^iv	−94.92 (10)	O4—P4—O9—K2ⁱ	101.62 (9)
K1^xv—P4—O8—K2^iv	94.78 (6)	O4—P4—O9—P3^xi	−65.16 (17)
K1^xi—P4—O9—K2ⁱ	−179.35 (6)	O4—P4—O10—K1^xv	152.89 (10)
K1^xv—P4—O9—K2ⁱ	−51.64 (8)	O4—P4—O10—K2	12.62 (13)
K1^xv—P4—O9—P3^xi	141.58 (13)	O4—P4—O10—K2ⁱ	−99.99 (9)
K1^xi—P4—O9—P3^xi	13.87 (15)	O5—P1—O1—P2	16.13 (19)
K1^xi—P4—O10—K1^xv	45.8 (3)	O5—P1—O4—K2	13.82 (11)
K1^xi—P4—O10—K2ⁱ	153.0 (2)	O5—P1—O4—P4	142.7 (3)
K1^xv—P4—O10—K2	−140.27 (15)	O5—P1—O7—Ni1^iv	61.21 (15)
K1^xi—P4—O10—K2	−94.4 (2)	O5—P1—O7—K1^xi	−174.00 (8)
K1^xv—P4—O10—K2ⁱ	107.12 (10)	O5—P1—O7—K2^iv	−70.88 (11)
K2^iv—P1—O1—P2	174.58 (7)	O6—P2—O1—P1	133.43 (16)
K2^iv—P1—O4—K2	−83.38 (6)	O6—P2—O2—Ni1	−140.52 (12)
K2^iv—P1—O4—P4	45.5 (3)	O6—P2—O2—K1ⁱ	119.39 (9)
K2^iv—P1—O5—Ni1	171.95 (10)	O6—P2—O3—K1ⁱ	−126.86 (8)
K2^iv—P1—O5—K2	69.00 (5)	O6—P2—O3—P3	42.01 (19)
K2^iv—P1—O7—Ni1^iv	132.09 (15)	O7—P1—O1—P2	149.54 (15)
K2^iv—P1—O7—K1^xi	−103.12 (10)	O7—P1—O4—K2	−116.23 (9)
K2^xiii—P2—O1—P1	163.00 (16)	O7—P1—O4—P4	12.7 (3)
K2^xiii—P2—O2—Ni1	−135.19 (15)	O7—P1—O5—Ni1	−146.17 (12)
K2^xiii—P2—O2—K1ⁱ	124.72 (18)	O7—P1—O5—K2	110.88 (9)
K2^xiii—P2—O3—K1ⁱ	−162.76 (6)	O8—P4—O4—K2	121.90 (8)
K2^xiii—P2—O3—P3	6.11 (15)	O8—P4—O4—P1	−10.7 (3)
K2^xiii—P2—O6—Ni1ⁱ	−127.23 (17)	O8—P4—O9—K2ⁱ	−142.14 (9)
K2^xiii—P2—O6—K1^xii	111.29 (12)	O8—P4—O9—P3^xi	51.08 (18)
K2^xiii—P3—O3—K1ⁱ	161.44 (8)	O8—P4—O10—K1^xv	27.62 (15)
K2^xiv—P3—O3—K1ⁱ	18.10 (11)	O8—P4—O10—K2	−112.65 (11)
K2^xiii—P3—O3—P2	−6.24 (16)	O8—P4—O10—K2ⁱ	134.73 (9)
K2^xiv—P3—O3—P2	−149.58 (13)	O9^ix—P3—O3—K1ⁱ	−155.84 (9)
K2^xiii—P3—O11—Ni1^xiii	85.23 (15)	O9^ix—P3—O3—P2	36.48 (18)
K2^xiv—P3—O11—Ni1^xiii	−80.91 (15)	O9^ix—P3—O11—Ni1^xiii	63.04 (18)
K2^xiii—P3—O11—K1^xii	−74.63 (8)	O9^ix—P3—O11—K1^xii	−96.82 (10)
K2^xiv—P3—O11—K1^xii	119.23 (10)	O9^ix—P3—O11—K2^xiv	143.95 (7)
K2^xiii—P3—O11—K2^xiv	166.14 (5)	O9^ix—P3—O12—K1	37.38 (18)
K2^xiii—P3—O12—K1	62.0 (2)	O9^ix—P3—O12—K2^xiv	−143.87 (8)
K2^xiv—P3—O12—K1	−178.75 (19)	O9—P4—O4—K2	−120.65 (7)
K2^xiii—P3—O12—K2^xiv	−119.20 (14)	O9—P4—O4—P1	106.8 (3)
K2ⁱ—P4—O4—K2	−74.83 (5)	O9—P4—O8—Ni1^xvi	77.6 (2)
K2—P4—O4—P1	−132.6 (3)	O9—P4—O8—K1^xi	−62.80 (11)
K2ⁱ—P4—O4—P1	152.6 (3)	O9—P4—O8—K2^iv	−157.72 (8)
K2ⁱ—P4—O8—Ni1^xvi	34.6 (3)	O9—P4—O10—K1^xv	−99.86 (11)
K2—P4—O8—Ni1^xvi	−101.76 (18)	O9—P4—O10—K2	119.87 (9)
K2—P4—O8—K1^xi	117.88 (7)	O9—P4—O10—K2ⁱ	7.26 (9)
K2ⁱ—P4—O8—K1^xi	−105.80 (10)	O10—P4—O4—K2	−10.01 (10)
K2—P4—O8—K2^iv	22.96 (11)	O10—P4—O4—P1	−142.6 (3)
K2ⁱ—P4—O8—K2^iv	159.29 (5)	O10—P4—O8—Ni1^xvi	−47.6 (2)
K2—P4—O9—K2ⁱ	37.22 (10)	O10—P4—O8—K1^xi	172.04 (9)
K2—P4—O9—P3^xi	−129.56 (12)	O10—P4—O8—K2^iv	77.12 (12)
K2ⁱ—P4—O9—P3^xi	−166.8 (2)	O10—P4—O9—K2ⁱ	−9.12 (11)
K2ⁱ—P4—O10—K1^xv	−107.12 (10)	O10—P4—O9—P3^xi	−175.90 (14)
K2—P4—O10—K1^xv	140.27 (15)	O11—P3—O3—K1ⁱ	92.39 (11)
K2—P4—O10—K2ⁱ	−112.61 (10)	O11—P3—O3—P2	−75.29 (18)
K2ⁱ—P4—O10—K2	112.61 (10)	O11—P3—O12—K1	164.75 (12)
O1—P1—O4—K2	130.66 (8)	O11—P3—O12—K2^xiv	−16.50 (12)
O1—P1—O4—P4	−100.4 (3)	O12—P3—O3—K1ⁱ	−36.92 (13)
O1—P1—O5—Ni1	−19.87 (16)	O12—P3—O3—P2	155.39 (15)
O1—P1—O5—K2	−122.82 (8)	O12—P3—O11—Ni1^xiii	−67.17 (19)
O1—P1—O7—Ni1^iv	−67.44 (13)	O12—P3—O11—K1^xii	132.98 (10)
O1—P1—O7—K1^xi	57.35 (10)	O12—P3—O11—K2^xiv	13.74 (10)
O1—P1—O7—K2^iv	160.47 (8)

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

Acknowledgements

The authors are grateful to the Service de Coopération et d'Action Culturelle (SCAC) de l'Ambassade de France en Mauritanie for financial support and Professor Claude Lecomte and coworkers of the Laboratoire CRM2 of the Université de Lorraine (France) for their help.

References

Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Daidouh, A., Pico, C. & Veiga, M. L. (1999). Solid State Ionics, 124, 109–117. Web of Science CrossRef ICSD CAS Google Scholar
El Maadi, A., Boukhari, A. & Holt, E. M. (1995). J. Chem. Crystallogr. 25, 531–536. CAS Google Scholar
Essehli, R., Belharouak, I., Ben Yahia, H., Chamoun, R., Orayech, B., El Bali, B., Bouziane, K., Zhou, X. L. & Zhou, Z. (2015). Dalton Trans. 44, 4526–4532. Web of Science CrossRef CAS PubMed Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Fischer, P., Luján, M., Kubel, F. & Schmid, H. (1994). Ferroelectrics, 162, 37–44. CrossRef ICSD Google Scholar
Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171–179. Web of Science CrossRef IUCr Journals Google Scholar
Hatert, F., Long, G. J., Hautot, D., Fransolet, A. M., Delwiche, J., Hubin-Franskin, M. J. & Grandjean, F. (2004). Phys. Chem. Miner. 31, 487–506. Web of Science CrossRef ICSD CAS Google Scholar
Kapshuk, A. A., Nagornyï, P. G. & Petrenko, O. V. (2000). Crystallogr. Rep. 45, 206–209. CrossRef Google Scholar
La Parola, V., Liveri, V. T., Todaro, L., Lombardo, D., Bauer, E. M., Dell'Era, A., Longo, A., Caschera, D., de Caro, T., Toro, R. G. & Calandra, P. (2018). Mater. Lett. 220, 58–61. CAS Google Scholar
Lazoryak, B. I., Morozov, V. A., Belik, A. A., Stefanovich, S. Y., Grebenev, V. V., Leonidov, I. A., Mitberg, E. B., Davydov, S. A., Lebedev, O. I. & Van Tendeloo, G. (2004). Solid State Sci. 6, 185–195. Web of Science CrossRef ICSD CAS Google Scholar
Litvin, B. N. & Masloboev, V. A. (1989). Rare Earth Phosphates, edited by R. Grebentshikov. Moscow: Nauka Publishing. Google Scholar
Moffat, J. B. (1978). Catal. Rev. 18, 199–258. CrossRef CAS Web of Science Google Scholar
Moutataouia, M., Lamire, M., Saadi, M. & El Ammari, L. (2014). Acta Cryst. E70, i5. CSD CrossRef IUCr Journals Google Scholar
Orikasa, Y., Gogyo, Y., Yamashige, H., Katayama, M., Chen, K., Mori, T., Yamamoto, K., Masese, T., Inada, Y., Ohta, T., Siroma, Z., Kato, S., Kinoshita, H., Arai, H., Ogumi, Z. & Uchimoto, Y. (2016). Sci. Rep. 6, 26382. CrossRef PubMed Google Scholar
Ouaatta, S., Assani, A., Saadi, M. & El Ammari, L. (2019). Acta Cryst. E75, 402–404. Web of Science CrossRef ICSD IUCr Journals Google Scholar
Palkina, K. K. & Maksimova, S. I. (1980). Dokl. Akad. Nauk SSSR, 250, 1130–1134. CAS Google Scholar
Panahandeh, A. & Jung, W. (2003). Z. Anorg. Allg. Chem. 629, 1651–1660. CrossRef ICSD CAS Google Scholar
Pontchara, P. & Durif, A. (1974). C. R. Acad. Sci. C, 278, 175–178. Google Scholar
Rigaku OD (2022). CrysAlis PRO. Rigaku Oxford Diffraction, Yarnton, England. Google Scholar
Sbai, K., Belaaouad, S., Kenz, A., Tace, E. M. & Tridane, M. (2004). Powder Diffr. 19, 375–377. CrossRef CAS Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar