NASICON-related Na3.4Mn0.4Fe1.6(PO4)3

Yatskin, M.M.; Strutynska, N.Y.; Baumer, V.N.; Ogorodnyk, I.V.; Slobodyanik, N.S.

doi:10.1107/S1600536812027584

inorganic compounds

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Volume 68| Part 7| July 2012| Page i55

https://doi.org/10.1107/S1600536812027584

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NASICON-related Na_3.4Mn_0.4Fe_1.6(PO₄)₃

Michael M. Yatskin,^a ^* Nataliya Yu. Strutynska,^a Vyacheslav N. Baumer,^b Ivan V. Ogorodnyk ^a and Nikolay S. Slobodyanik ^a

^aDepartment of Inorganic Chemistry, Taras Shevchenko National University, 64 Volodymyrska str., 01601 Kyiv, Ukraine, and ^bSTC "Institute for Single Crystals", NAS of Ukraine, 60 Lenin ave., 61001 Kharkiv, Ukraine
^*Correspondence e-mail: yats_13@ukr.net

(Received 31 May 2012; accepted 18 June 2012; online 23 June 2012)

The solid solution, sodium [iron(III)/manganese(II)] tris(orthophosphate), Na_3.4Mn_0.4Fe_1.6(PO₄)₃, was obtained using a flux method. Its crystal structure is related to that of NASICON-type compounds. The [(Mn/Fe)₂(PO₄)₃] framework is built up from an (Mn/Fe)O₆ octahedron (site symmetry 3.), with a mixed Mn/Fe occupancy, and a PO₄ tetrahedron (site symmetry .2). The Na⁺ cations are distributed over two partially occupied sites in the cavities of the framework. One Na⁺ cation (site symmetry -3.) is surrounded by six O atoms, whereas the other Na⁺ cation (site symmetry .2) is surrounded by eight O atoms.

Related literature

For applications and properties of NASICON-related compounds, see: Goodenough et al. (1976 ); Shimizu & Ushijima (2000 ); Veríssimo et al. (1997 ); Mariappan et al. (2005 ); Arbi et al. (2002 ); Moreno-Real et al. (2002 ). For details of structural relationships with other compounds, see: γ-Na₃Fe₂(PO₄)₃ (Masquelier et al., 2000 ); Na₄Fe₂(PO₄)₃ (Hatert, 2009 ); Na₄MgFe(PO₄)₃ (Strutynska et al., 2012 ); Na₄NiFe(PO₄)₃ (Essehli et al., 2011 ).

Experimental

Crystal data

Na_3.4Mn_0.4Fe_1.6(PO₄)₃
M_r = 474.41
Trigonal, $[R \overline 3c ]$
a = 8.8694 (2) Å
c = 21.6074 (7) Å
V = 1472.05 (7) Å³
Z = 6
Mo Kα radiation
μ = 3.59 mm⁻¹
T = 293 K
0.10 × 0.10 × 0.08 mm

Data collection

Oxford Diffraction Xcalibur-3 diffractometer
Absorption correction: multi-scan (Blessing, 1995 ) T_min = 0.721, T_max = 0.795
8867 measured reflections
728 independent reflections
658 reflections with I > 2σ(I)
R_int = 0.033

Refinement

R[F² > 2σ(F²)] = 0.028
wR(F²) = 0.072
S = 1.23
728 reflections
38 parameters
2 restraints
Δρ_max = 0.66 e Å⁻³
Δρ_min = −0.39 e Å⁻³

Table 1
Selected bond lengths (Å)

Na1—O2	2.4546 (15)
Na2—O2ⁱ	2.4505 (16)
Na2—O2ⁱⁱ	2.472 (2)
Na2—O1ⁱ	2.587 (2)
Na2—O1ⁱⁱⁱ	2.921 (2)
Fe1—O1	1.9962 (16)
Fe1—O2	2.1053 (15)
P1—O1	1.5244 (16)
P1—O2ⁱⁱ	1.5346 (15)
Symmetry codes: (i) $[y+{\script{2\over 3}}, -x+y+{\script{1\over 3}}, -z+{\script{1\over 3}}]$ ; (ii) $[-x+y+{\script{1\over 3}}, y-{\script{1\over 3}}, z+{\script{1\over 6}}]$ ; (iii) $[y+1, x, -z+{\script{1\over 2}}]$ .

Data collection: CrysAlis CCD (Oxford Diffraction, 2006 $[Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]$ ); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2006 $[Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]$ ); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999 ); software used to prepare material for publication: WinGX (Farrugia, 1999 ) and enCIFer (Allen et al., 2004 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: https://doi.org/10.1107/S1600536812027584/wm2642sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536812027584/wm2642Isup2.hkl

checkCIF report

Comment top

NASICON-type compounds possess high ionic conductivity, chemical stability and attract great interest for application in solid-state electrochemical devices (Goodenough et al., 1976; Shimizu & Ushijima, 2000; Veríssimo et al., 1997; Mariappan et al., 2005; Arbi et al., 2002; Moreno-Real et al., 2002).

Herein, the structure of Na_3.4Mn_0.4Fe_1.6(PO₄)₃, (I), is reported. Compound (I) can be considered as a solid solution of γ-Na₃Fe₂(PO₄)₃ (Masquelier et al., 2000) and belongs to the NASICON structure type.

There are two Na sites (Wyckoff positions 6b and 18e), one mixed occupied Mn/Fe site (12c), one P site (18e) and two O sites (36f) in the asymmetric unit of (I) (Fig. 1). The basic building block of the structure is the [(Mn/Fe)₂(PO₄)₃] unit, which consists of two (Mn/Fe)O₆ polyhedra interlinked by three bridging PO₄-tetrahedra (Fig. 2). These fragments alternate with Na1O₆-polyhedra along [001] forming ribbons, which in turn are interconnected by PO₄-tetrahedra forming a three-dimensional framework (Fig. 2). The distances M—O in the (Mn/Fe)O₆ octahedra vary from 1.9962 (16) to 2.1053 (15) Å and are similar to that in isotypic structures (e.g. 1.956 (2)–2.048 (2) Å in γ-Na₃Fe₂(PO₄)₃ (Masquelier et al., 2000); 2.010 (6)–2.130 (6) Å in Na₄Fe₂(PO₄)₃ (Hatert, 2009); 1.926 (5)–2.037 (6) Å in Na₄MgFe(PO₄)₃ (Strutynska et al., 2012); 1.955 (3)–2.050 (3) Å in Na₄NiFe(PO₄)₃ (Essehli et al., 2011). The P atom has an almost regular tetrahedral coordination, the P—O distances in the PO₄ tetrahedra being in the range 1.5244 (16)–1.5346 (15) Å, as is typically observed in NASICON-type phosphates. Two types of sodium atoms occupy the cavities of the framework. The Na1 atoms (s.o.f. = 0.848 (5)) lie on a threefold roto-inversion axis and are surrounded by six O2 atoms in a distance of 2.4546 (15) Å. The Na2 (s.o.f. = 0.853 (5)) coordination environment is formed by eight oxygen atoms with four pairs of equal contacts (d(Na2—O) = 2.4505 (16)–2.921 (2) Å, using a cut-off distance of 3.1 Å).

Related literature top

For applications and properties of NASICON-related compounds, see: Goodenough et al. (1976); Shimizu & Ushijima (2000); Veríssimo et al. (1997); Mariappan et al. (2005); Arbi et al. (2002); Moreno-Real et al. (2002). For details of structural relationships with other compounds, see: γ-Na₃Fe₂(PO₄)₃ (Masquelier et al., 2000); Na₄Fe₂(PO₄)₃ (Hatert, 2009); Na₄MgFe(PO₄)₃ (Strutynska et al., 2012); Na₄NiFe(PO₄)₃ (Essehli et al., 2011).

Experimental top

The title compound was obtained during investigation of the melting system Na₂O–P₂O₅–Fe₂O₃–MnO. A mixture of NaPO₃ (12.24 g), Na₂CO₃ (1.908 g), Fe₂O₃ (2.4 g) and MnCO₃^.Mn(OH)₂ (3.8 g) was ground in an agate mortar, placed in a platinum crucible and heated up to 1273 K. The melt was kept at this temperature for 3 h. After that, the temperature was cooled down to 973 K at a rate of 10 K/h. The light-violet crystals of (I) were recovered using hot water. The chemical composition of single-crystal was verified using EDX analysis. Analysis found: Na 16.62, Mn 2.14, Fe 7.93, P 14.94 and O 58.37 at%, while Na_3.4Mn_0.4Fe_1.6(PO₄)₃ requires Na 16.67, Mn 1.96, Fe 7.84, P 14.70 and O 58.82 at%.

Structure description top

For applications and properties of NASICON-related compounds, see: Goodenough et al. (1976); Shimizu & Ushijima (2000); Veríssimo et al. (1997); Mariappan et al. (2005); Arbi et al. (2002); Moreno-Real et al. (2002). For details of structural relationships with other compounds, see: γ-Na₃Fe₂(PO₄)₃ (Masquelier et al., 2000); Na₄Fe₂(PO₄)₃ (Hatert, 2009); Na₄MgFe(PO₄)₃ (Strutynska et al., 2012); Na₄NiFe(PO₄)₃ (Essehli et al., 2011).

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis CCD (Oxford Diffraction, 2006); data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999) and enCIFer (Allen et al., 2004).

Figures top

	Fig. 1. The asymmetric unit of (I), showing displacement ellipsoids at the 50% probability level.
	Fig. 2. Elementary fragments and three-dimensional framework in the title compound.

[iron(III)/manganese(II)] tris(orthophosphate) top

Crystal data top

Na_3.4Mn_0.4Fe_1.6(PO₄)₃	D_x = 3.212 Mg m⁻³
M_r = 474.41	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3c	Cell parameters from 8867 reflections
Hall symbol: -R 3 2" c	θ = 3.3–35.0°
a = 8.8694 (2) Å	µ = 3.59 mm⁻¹
c = 21.6074 (7) Å	T = 293 K
V = 1472.05 (7) Å³	Prism, light-violet
Z = 6	0.10 × 0.10 × 0.08 mm
F(000) = 1380

Data collection top

Oxford Diffraction Xcalibur-3 diffractometer	728 independent reflections
Radiation source: fine-focus sealed tube	658 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.033
φ and ω scans	θ_max = 35.0°, θ_min = 3.3°
Absorption correction: multi-scan (Blessing, 1995)	h = −14→14
T_min = 0.721, T_max = 0.795	k = −13→14
8867 measured reflections	l = −34→34

Refinement top

Refinement on F²	2 restraints
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F² > 2σ(F²)] = 0.028	Secondary atom site location: difference Fourier map
wR(F²) = 0.072	w = 1/[σ²(F_o²) + (0.0324P)² + 3.4282P] where P = (F_o² + 2F_c²)/3
S = 1.23	(Δ/σ)_max = 0.064
728 reflections	Δρ_max = 0.66 e Å⁻³
38 parameters	Δρ_min = −0.39 e Å⁻³

Crystal data top

Na_3.4Mn_0.4Fe_1.6(PO₄)₃	Z = 6
M_r = 474.41	Mo Kα radiation
Trigonal, R3c	µ = 3.59 mm⁻¹
a = 8.8694 (2) Å	T = 293 K
c = 21.6074 (7) Å	0.10 × 0.10 × 0.08 mm
V = 1472.05 (7) Å³

Data collection top

Oxford Diffraction Xcalibur-3 diffractometer	728 independent reflections
Absorption correction: multi-scan (Blessing, 1995)	658 reflections with I > 2σ(I)
T_min = 0.721, T_max = 0.795	R_int = 0.033
8867 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.028	38 parameters
wR(F²) = 0.072	2 restraints
S = 1.23	Δρ_max = 0.66 e Å⁻³
728 reflections	Δρ_min = −0.39 e Å⁻³

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
Na1	0	0	0	0.0322 (8)	0.848 (5)
Na2	0.63677 (18)	0	0.25	0.0356 (6)	0.853 (5)
Fe1	0	0	0.149480 (18)	0.01045 (11)	0.7991 (12)
Mn1	0	0	0.149480 (18)	0.01045 (11)	0.2009 (12)
P1	0.29637 (7)	0	0.25	0.01144 (13)
O1	0.1887 (2)	−0.0197 (3)	0.19242 (8)	0.0346 (4)
O2	0.18883 (19)	0.17055 (18)	0.08615 (7)	0.0214 (3)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Na1	0.0421 (11)	0.0421 (11)	0.0124 (10)	0.0211 (6)	0	0
Na2	0.0206 (6)	0.0151 (7)	0.0694 (14)	0.0075 (3)	0.0068 (4)	0.0136 (7)
Fe1	0.01042 (13)	0.01042 (13)	0.01049 (17)	0.00521 (7)	0	0
Mn1	0.01042 (13)	0.01042 (13)	0.01049 (17)	0.00521 (7)	0	0
P1	0.01059 (19)	0.0092 (2)	0.0141 (2)	0.00459 (12)	0.00093 (9)	0.00185 (18)
O1	0.0270 (8)	0.0404 (10)	0.0327 (8)	0.0142 (7)	−0.0155 (7)	0.0016 (7)
O2	0.0157 (6)	0.0139 (6)	0.0274 (7)	0.0021 (5)	−0.0002 (5)	0.0021 (5)

Geometric parameters (Å, º) top

Na1—O2ⁱ	2.4546 (15)	Na2—O1^x	2.921 (2)
Na1—O2	2.4546 (15)	Na2—O1^xi	2.921 (2)
Na1—O2ⁱⁱ	2.4546 (15)	Fe1—O1ⁱⁱ	1.9962 (16)
Na1—O2ⁱⁱⁱ	2.4546 (15)	Fe1—O1ⁱⁱⁱ	1.9962 (16)
Na1—O2^iv	2.4546 (15)	Fe1—O1	1.9962 (16)
Na1—O2^v	2.4546 (15)	Fe1—O2ⁱⁱ	2.1053 (15)
Na2—O2^vi	2.4505 (16)	Fe1—O2ⁱⁱⁱ	2.1053 (15)
Na2—O2^vii	2.4505 (16)	Fe1—O2	2.1053 (15)
Na2—O2^viii	2.472 (2)	P1—O1	1.5244 (16)
Na2—O2^ix	2.472 (2)	P1—O1^xii	1.5244 (16)
Na2—O1^vii	2.587 (2)	P1—O2^ix	1.5346 (15)
Na2—O1^vi	2.587 (2)	P1—O2^viii	1.5346 (15)

O2ⁱ—Na1—O2	180.00 (5)	O1^vii—Na2—O1^xi	109.85 (7)
O2ⁱ—Na1—O2ⁱⁱ	111.27 (5)	O1^vi—Na2—O1^xi	86.08 (4)
O2—Na1—O2ⁱⁱ	68.73 (5)	O1^x—Na2—O1^xi	81.67 (9)
O2ⁱ—Na1—O2ⁱⁱⁱ	111.27 (5)	O1ⁱⁱ—Fe1—O1ⁱⁱⁱ	100.14 (7)
O2—Na1—O2ⁱⁱⁱ	68.73 (5)	O1ⁱⁱ—Fe1—O1	100.14 (7)
O2ⁱⁱ—Na1—O2ⁱⁱⁱ	68.73 (5)	O1ⁱⁱⁱ—Fe1—O1	100.14 (7)
O2ⁱ—Na1—O2^iv	68.73 (5)	O1ⁱⁱ—Fe1—O2ⁱⁱ	87.95 (7)
O2—Na1—O2^iv	111.27 (5)	O1ⁱⁱⁱ—Fe1—O2ⁱⁱ	167.15 (7)
O2ⁱⁱ—Na1—O2^iv	111.27 (5)	O1—Fe1—O2ⁱⁱ	88.10 (7)
O2ⁱⁱⁱ—Na1—O2^iv	180.00 (8)	O1ⁱⁱ—Fe1—O2ⁱⁱⁱ	88.10 (7)
O2ⁱ—Na1—O2^v	68.73 (5)	O1ⁱⁱⁱ—Fe1—O2ⁱⁱⁱ	87.95 (7)
O2—Na1—O2^v	111.27 (5)	O1—Fe1—O2ⁱⁱⁱ	167.15 (7)
O2ⁱⁱ—Na1—O2^v	180.00 (9)	O2ⁱⁱ—Fe1—O2ⁱⁱⁱ	82.32 (6)
O2ⁱⁱⁱ—Na1—O2^v	111.27 (5)	O1ⁱⁱ—Fe1—O2	167.15 (7)
O2^iv—Na1—O2^v	68.73 (5)	O1ⁱⁱⁱ—Fe1—O2	88.10 (7)
O2^vi—Na2—O2^vii	162.12 (10)	O1—Fe1—O2	87.95 (7)
O2^vi—Na2—O2^viii	129.35 (6)	O2ⁱⁱ—Fe1—O2	82.32 (6)
O2^vii—Na2—O2^viii	68.52 (7)	O2ⁱⁱⁱ—Fe1—O2	82.32 (6)
O2^vi—Na2—O2^ix	68.52 (7)	O1—P1—O1^xii	110.62 (16)
O2^vii—Na2—O2^ix	129.35 (6)	O1—P1—O2^ix	112.19 (10)
O2^viii—Na2—O2^ix	60.85 (8)	O1^xii—P1—O2^ix	106.30 (9)
O2^vi—Na2—O1^vii	114.64 (5)	O1—P1—O2^viii	106.30 (9)
O2^vii—Na2—O1^vii	68.83 (5)	O1^xii—P1—O2^viii	112.19 (10)
O2^viii—Na2—O1^vii	68.62 (6)	O2^ix—P1—O2^viii	109.33 (12)
O2^ix—Na2—O1^vii	93.19 (7)	P1—O1—Fe1	150.92 (13)
O2^vi—Na2—O1^vi	68.83 (5)	P1—O1—Na2^xiii	120.86 (11)
O2^vii—Na2—O1^vi	114.64 (5)	Fe1—O1—Na2^xiii	86.63 (6)
O2^viii—Na2—O1^vi	93.19 (7)	P1—O1—Na2^xiv	76.78 (7)
O2^ix—Na2—O1^vi	68.62 (6)	Fe1—O1—Na2^xiv	102.77 (7)
O1^vii—Na2—O1^vi	159.36 (11)	Na2^xiii—O1—Na2^xiv	112.45 (8)
O2^vi—Na2—O1^x	53.35 (5)	P1^ix—O2—Fe1	141.73 (9)
O2^vii—Na2—O1^x	111.21 (7)	P1^ix—O2—Na2^xiii	93.51 (8)
O2^viii—Na2—O1^x	153.24 (6)	Fe1—O2—Na2^xiii	87.96 (6)
O2^ix—Na2—O1^x	114.32 (5)	P1^ix—O2—Na1	128.40 (8)
O1^vii—Na2—O1^x	86.07 (4)	Fe1—O2—Na1	89.86 (5)
O1^vi—Na2—O1^x	109.85 (7)	Na2^xiii—O2—Na1	86.38 (5)
O2^vi—Na2—O1^xi	111.22 (7)	P1^ix—O2—Na2^ix	94.91 (7)
O2^vii—Na2—O1^xi	53.35 (5)	Fe1—O2—Na2^ix	87.39 (6)
O2^viii—Na2—O1^xi	114.32 (5)	Na2^xiii—O2—Na2^ix	171.00 (7)
O2^ix—Na2—O1^xi	153.24 (6)	Na1—O2—Na2^ix	85.91 (5)

Symmetry codes: (i) −x, −y, −z; (ii) −x+y, −x, z; (iii) −y, x−y, z; (iv) y, −x+y, −z; (v) x−y, x, −z; (vi) y+2/3, −x+y+1/3, −z+1/3; (vii) x+1/3, x−y−1/3, z+1/6; (viii) −x+y+1/3, y−1/3, z+1/6; (ix) −x+2/3, −y+1/3, −z+1/3; (x) y+1, x, −z+1/2; (xi) −x+y+1, −x, z; (xii) x−y, −y, −z+1/2; (xiii) x−y−1/3, x−2/3, −z+1/3; (xiv) −y, x−y−1, z.

Experimental details

Crystal data
Chemical formula	Na_3.4Mn_0.4Fe_1.6(PO₄)₃
M_r	474.41
Crystal system, space group	Trigonal, R3c
Temperature (K)	293
a, c (Å)	8.8694 (2), 21.6074 (7)
V (Å³)	1472.05 (7)
Z	6
Radiation type	Mo Kα
µ (mm⁻¹)	3.59
Crystal size (mm)	0.10 × 0.10 × 0.08

Data collection
Diffractometer	Oxford Diffraction Xcalibur-3
Absorption correction	Multi-scan (Blessing, 1995)
T_min, T_max	0.721, 0.795
No. of measured, independent and observed [I > 2σ(I)] reflections	8867, 728, 658
R_int	0.033
(sin θ/λ)_max (Å⁻¹)	0.807

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.028, 0.072, 1.23
No. of reflections	728
No. of parameters	38
No. of restraints	2
Δρ_max, Δρ_min (e Å⁻³)	0.66, −0.39

Computer programs: CrysAlis CCD (Oxford Diffraction, 2006), CrysAlis RED (Oxford Diffraction, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 1999), WinGX (Farrugia, 1999) and enCIFer (Allen et al., 2004).

Selected bond lengths (Å) top

Na1—O2	2.4546 (15)	Fe1—O1	1.9962 (16)
Na2—O2ⁱ	2.4505 (16)	Fe1—O2	2.1053 (15)
Na2—O2ⁱⁱ	2.472 (2)	P1—O1	1.5244 (16)
Na2—O1ⁱ	2.587 (2)	P1—O2ⁱⁱ	1.5346 (15)
Na2—O1ⁱⁱⁱ	2.921 (2)

Symmetry codes: (i) y+2/3, −x+y+1/3, −z+1/3; (ii) −x+y+1/3, y−1/3, z+1/6; (iii) y+1, x, −z+1/2.

Acknowledgements

The authors are grateful to Dr. Igor V. Zatovsky from Department of Inorganic Chemistry, Taras Shevchenko National University, Kiev, Ukraine, for valuable comments and support.

References

Allen, F. H., Johnson, O., Shields, G. P., Smith, B. R. & Towler, M. (2004). J. Appl. Cryst. 37, 335–338. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Arbi, K., Mandal, S., Rojo, J. M. & Sanz, J. (2002). Chem. Mater. 14, 1091–1097. Web of Science CrossRef CAS Google Scholar
Blessing, R. H. (1995). Acta Cryst. A51, 33–38. CrossRef CAS Web of Science IUCr Journals Google Scholar
Brandenburg, K. (1999). DIAMOND. University of Bonn, Germany. Google Scholar
Essehli, R., Bali, B. E., Benmokhtar, S., Bouziane, K., Manoun, B., Abdalslam, M. A. & Ehrenberg, H. (2011). J. Alloys Compd, 509, 1163–1171. Web of Science CrossRef CAS Google Scholar
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838. CrossRef CAS IUCr Journals Google Scholar
Goodenough, J. B., Hong, H. Y. P. & Kafalas, J. A. (1976). Mater. Res. Bull. 11, 203–220. CrossRef CAS Web of Science Google Scholar
Hatert, F. (2009). Acta Cryst. E65, i30. Web of Science CrossRef IUCr Journals Google Scholar
Mariappan, C. R., Govindaraj, G. & Roling, B. (2005). Solid State Ionics, 176, 723–729. Web of Science CrossRef CAS Google Scholar
Masquelier, C., Wurm, C., Rodríguez-Carvajal, J., Gaubicher, J. & Nazar, L. (2000). Chem. Mater. 12, 525–532. Web of Science CrossRef CAS Google Scholar
Moreno-Real, L., Maldonado-Manso, P., Leon-Reina, L., Losilla, E. R., Mouahid, F. E., Zahir, M. & Sanz, J. (2002). J. Mater. Chem. 12, 3681–3687. CAS Google Scholar
Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Shimizu, Y. & Ushijima, T. (2000). Solid State Ionics, 132, 143–148. Web of Science CrossRef CAS Google Scholar
Strutynska, N. Yu., Zatovsky, I. V., Yatskin, M. M., Slobodyanik, N. S. & Ogorodnyk, I. V. (2012). Inorg. Mater. 48, 402–406. Web of Science CrossRef CAS Google Scholar
Veríssimo, C., Garrido, F. M. S., Alves, O. L., Calle, P., Martínez-Juárezc, A., Iglesias, J. E. & Rojo, J. M. (1997). Solid State Ionics, 100, 127–134. Google Scholar