Mixed-metal phosphates K1.64Na0.36TiFe(PO4)3 and K0.97Na1.03Ti1.26Fe0.74(PO4)3 with a langbeinite framework

Zatovsky, I.V.; Strutynska, N.Y.; Ogorodnyk, I.V.; Baumer, V.N.; Slobodyanik, N.S.; Butenko, D.S.

doi:10.1107/S2056989021011877

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ISSN: 2056-9890

Volume 77| Part 12| December 2021| Pages 1299-1302

https://doi.org/10.1107/S2056989021011877

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Mixed-metal phosphates K_1.64Na_0.36TiFe(PO₄)₃ and K_0.97Na_1.03Ti_1.26Fe_0.74(PO₄)₃ with a langbeinite framework

Igor V. Zatovsky,^a ^* Nataliia Yu. Strutynska,^b Ivan V. Ogorodnyk,^c Vyacheslav N. Baumer,^d Nickolai S. Slobodyanik ^b and Denis S. Butenko ^e,^f

^aF.D. Ovcharenko Institute of Biocolloidal Chemistry, NAS Ukraine, 42 Acad. Vernadskoho blv., 03142 Kyiv, Ukraine, ^bDepartment of Inorganic Chemistry, Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska Str., 01601 Kyiv, Ukraine, ^cShimUkraine LLC 18, Chigorina Str., office 429, 01042 Kyiv, Ukraine, ^dSTC "Institute for Single Crystals", NAS of Ukraine, 60 Lenin ave., 61001 Kharkiv, Ukraine, ^eShenzhen Key Laboratory of Solid State Batteries, Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China, and ^fGuangdong Provincial Key Laboratory of Energy Materials for Electric Power, Southern University of Science and Technology, Shenzhen 518055, People's Republic of China
^*Correspondence e-mail: zvigo@ukr.net

Edited by M. Weil, Vienna University of Technology, Austria (Received 15 October 2021; accepted 9 November 2021; online 16 November 2021)

Single crystals of the langbeinite-type phosphates K_1.65Na_0.35TiFe(PO₄)₃ and K_0.97Na_1.03Ti_1.26Fe_0.74(PO₄)₃ were grown by crystallization from high-temperature self-fluxes in the system Na₂O–K₂O–P₂O₅–TiO₂–Fe₂O₃ using fixed molar ratios of (Na+K):P = 1.0, Ti:P = 0.20 and Na:K = 1.0 or 2.0 over the temperature range 1273–953 K. The three-dimensional framework of the two isotypic phosphates are built up from [(Ti/Fe)₂(PO₄)₃] structure units containing two mixed [(Ti/Fe)O₆] octahedra (site symmetry 3) connected via three bridging PO₄ tetrahedra. The potassium and sodium cations share two different sites in the structure that are located in the cavities of the framework. One of these sites has nine and the other twelve surrounding O atoms.

Keywords: crystal structure; phosphate; mixed occupancy; framework structure.

CCDC references: 2121192; 2121193

1. Chemical context

Over the last decade, numerous research efforts have been directed towards the creation of new phosphate materials for Li- or Na-ion batteries (Nose et al., 2013 ; Zhang et al., 2021 ). In particular, significant progress has been made for complex phosphates with general formula M^I₁₊_xZ₂(PO₄)₃ (M^I = Li, Na; Z = polyvalent metals; x values can range from 0 to 3; Zatovsky et al., 2016 ) adopting NASICON-type structures. The composition of phosphates with a langbeinite-type structure is very similar to the composition of NASICON-type ones, and langbeinite-type phosphates are also considered to be potential hosts for new electrode materials (Luo et al., 2019 ). However, langbeinite-type phosphates with a composition M^I₁₊_xZ₂(PO₄)₃ (x = 0–1) can only be prepared with large monovalent cations (e.g., K, Rb, Cs, NH₄; Norberg, 2002 ; Ogorodnyk et al., 2007a ). The langbeinite-type structure has only been reported for Na₂Z^IIITi(PO₄)₃ (Z^III = Cr, Fe; Isasi & Daidouh, 2000 ). More recently, a good prospect for using such kinds of materials as anodes for Na-ion batteries has been predicted because of the recently reported migration mechanisms in langbeinite-type Na₂CrTi(PO₄)₃ determined by atomic simulation (Luo et al., 2019). However, according to Wang et al. (2019 ), the phosphate Na₂CrTi(PO₄)₃ belongs to the family of compounds with a NASICON-type structure. Therefore, the issue of preparing Na-containing langbeinite-type phosphates requires further research and development. In recent years, the synthesis of K/Na-containing complex phosphates has been realized using the self-flux method and resulted in the compounds K_1.75Na_0.25Ti₂(PO₄)₃ (Zatovsky et al., 2018 ) and K_0.877Na_0.48Ti₂(PO₄)₃ (Strutynska et al., 2016 ).

Here, we report the preparation, structure analysis and characterization of two new mixed-metal phosphates K_1.64Na_0.36TiFe(PO₄)₃ (I) and K_0.97Na_1.03Ti_1.26Fe_0.74(PO₄)₃ (II), which are isotypic with the mineral langbeinite, K₂Mg₂(SO₄)₃ (Zemann & Zemann, 1957 ; Mereiter, 1979 ).

2. Structural commentary

As it is illustrated in Fig. 1, two pairs of mixed sites occupied by alkali metals (K/Na) and transition metals (Ti/Fe) are located on threefold rotation axes (Wyckoff position 4 a), whereas the P and all O atoms occupy general sites (12 b). In the structures, the main structural element for building of the three-dimensional framework is a [(Ti/Fe)₂(PO₄)₃] fragment consisting of two mixed-metal [(Ti/Fe)O₆] octahedra and three PO₄ tetrahedra (Fig. 2a). Such building units run in three orthogonal directions along the cubic space diagonals (Fig. 2b), which is typical for the langbeinite-related family of compounds (sulfates, phosphates, vanadates etc, Ogorodnyk et al., 2007a).

Figure 1
A view of the asymmetric units of (I) and (II), with displacement ellipsoids drawn at the 50% probability level.

Figure 2
(a) [(Ti/Fe)₂(PO₄)₃] building unit and (b) three-dimensional framework for (I) and (II).

Two octahedrally coordinated sites (Ti1/Fe1) and (Ti2/Fe2) show mixed occupancy with an Fe:Ti ratio close to 1:1. For (I), the Ti occupancy is 0.48 (3) for the M1 site, while for the M2 site it is 0.52 (3); for (II), the Ti occupancy is 0.61 (2) for the M1 site and 0.65 (2) for the M2 site. In the case of (I), this corresponds to Fe³⁺ and Ti⁴⁺ cations, while for (II), the simultaneous presence of Fe³⁺, Ti³⁺ and Ti⁴⁺ is suggested. The prepared crystals of (II) are violet in color and the Ti³⁺:Ti⁴⁺ ratio is about 1:4 taking into account the total charge of the cationic part of the compound. Partial self-reduction of Ti⁴⁺ to Ti³⁺ often accompanies the synthesis of langbeinite-type complex phosphates in fluxes of multicomponent systems when various trivalent or divalent metals are present (Gustafsson et al., 2005 ; Zatovskii et al., 2006 ). For structures (I) and (II), the [Ti/FeO₆] octahedra are slightly distorted (Tables 1 and 2). The range of M—O bond lengths [1.938 (2) – 1.976 (3) Å] is close to those in other langbeinite-related phosphates containing Ti and transition metals, such as K₂Fe_0.5Ti_1.5(PO₄)₃ [1.940 (2)–1.992 (2) Å]; K₂Ni_0.5Ti_1.5(PO₄)₃ [1.938 (5)–1.962 (5) Å]; K₂Co_0.5Ti_1.5(PO₄)₃ [1.945 (2)–1.974 (2) Å]; K₂Mn_0.5Ti_1.5(PO₄)₃ [1.961 (2)–2.002 (2) Å] (Ogorodnyk et al., 2008 , 2007b , 2006 ). The P—O distances for both structures are in the narrow ranges of 1.516 (4)–1.523 (3) for (I) and 1.517 (3)–1.523 (2) Å for (II).

Table 1
Selected bond lengths (Å) for (I)

Fe1—O2ⁱ	1.954 (3)	K2—O2^vi	2.911 (4)
Fe1—O1	1.976 (3)	K2—O4^vii	3.007 (4)
Fe2—O3ⁱⁱ	1.938 (3)	K2—O4^viii	3.231 (4)
Fe2—O4ⁱⁱⁱ	1.970 (3)	P3—O4	1.516 (4)
K1—O1^iv	2.830 (4)	P3—O2	1.522 (3)
K1—O2^v	3.019 (4)	P3—O3	1.523 (3)
K1—O4^v	3.129 (4)	P3—O1	1.523 (3)
K2—O3^v	2.854 (4)
Symmetry codes: (i) $[-z, x-{\script{1\over 2}}, -y+{\script{1\over 2}}]$ ; (ii) $[y+{\script{1\over 2}}, -z+{\script{1\over 2}}, -x+1]$ ; (iii) z, x, y; (iv) $[-z+{\script{1\over 2}}, -x+1, y+{\script{1\over 2}}]$ ; (v) $[z+{\script{1\over 2}}, -x+{\script{3\over 2}}, -y+1]$ ; (vi) $[x+{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+1]$ ; (vii) $[-y+1, z+{\script{1\over 2}}, -x+{\script{3\over 2}}]$ ; (viii) $[-z+1, x+{\script{1\over 2}}, -y+{\script{3\over 2}}]$ .

Table 2
Selected bond lengths (Å) for (II)

Fe1—O2ⁱ	1.940 (2)	K2—O2^vi	2.910 (3)
Fe1—O1	1.974 (2)	K2—O4^v	2.982 (4)
Fe2—O3ⁱⁱ	1.938 (2)	K2—O4^vii	3.237 (3)
Fe2—O4	1.954 (2)	P3—O4	1.517 (3)
K1—O1ⁱⁱⁱ	2.820 (3)	P3—O3	1.518 (2)
K1—O2^iv	3.009 (3)	P3—O2	1.520 (2)
K1—O4^v	3.122 (3)	P3—O1	1.523 (2)
K2—O3^v	2.843 (3)
Symmetry codes: (i) $[-z, x-{\script{1\over 2}}, -y+{\script{1\over 2}}]$ ; (ii) $[-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iii) $[-z+{\script{1\over 2}}, -x+1, y+{\script{1\over 2}}]$ ; (iv) $[-y+1, z+{\script{1\over 2}}, -x+{\script{3\over 2}}]$ ; (v) $[z+{\script{1\over 2}}, -x+{\script{3\over 2}}, -y+1]$ ; (vi) $[-y+{\script{3\over 2}}, -z+1, x+{\script{1\over 2}}]$ ; (vii) $[-z+1, x+{\script{1\over 2}}, -y+{\script{3\over 2}}]$ .

There are two sites where the alkali metal cations reside (Fig. 1). The first one, (K/Na)1 is occupied by K⁺ and Na⁺ cations at ratios of 0.85 (2):0.15 (2) and 0.676 (18):0.324 (18) for (I) and (II), respectively. The [(K/Na)1O₉] polyhedra show three sets of (K/Na)—O distances assuming a cut-off value for the contact lengths of 3.129 (4) Å; the bond lengths are similar for both structures (Tables 1 and 2). The coordination environment of the alkali cations related to the (K/Na)2 site consists of twelve O-atom neighbours with (K/Na)2—O distances ranging from 2.843 (3) to 3.237 (3) Å, which includes four sets of distances (Tables 1 and 2). For this site, the K:Na ratios are 0.80 (3):0.20 (3) for (I) and 0.294 (19):0.706 (19) for (II). An interesting fact is that the substitution of potassium by sodium in the position (K/Na)2 is greater for (II) than for (I), but the (K/Na)2—O distances change insignificantly.

3. Synthesis and crystallization

Phosphates (I) and (II) were obtained from the melts of the system Na₂O–K₂O–P₂O₅–TiO₂–Fe₂O₃ at fixed molar ratios of (Na+K)/P = 1.0, Ti/P = 0.20 and different values of Na/K = 1.0 or 2.0 over the temperature range 1273–953 K. All initial components M^IH₂PO₄ (M^I = Na, K), Fe₂O₃ and TiO₂ were of an analytical grade.

A mixture of KH₂PO₄ (10 g), NaH₂PO₄ (8.82 g), Fe₂O₃ (2.35 g) and TiO₂ (2.35 g) was used for the preparation of (I), while a mixture of KH₂PO₄ (10 g), NaH₂PO₄ (17.64 g), Fe₂O₃ (3.53 g) and TiO₂ (3.53 g) was used for the preparation of (II). In both cases, the mixtures of calculated amounts of starting components were ground in an agate mortar and melted in a platinum crucible at 1273 K. The obtained melts were kept under isothermal conditions for 2 h for dissolving of the corresponding TiO₂ + Fe₂O₃ mixture in the phosphate melt. Then the temperature was decreased with a rate of 25 K h⁻¹ to 953 K and kept at this temperature for 2 h before cooling down to room temperature by turning off the furnace power. The obtained crystalline phases were separated from soluble salts by leaching with hot water and dried at 373 K.

The molar ratio Na/K in the initial melts had an influence on the composition of the obtained crystals. Light-yellow crystals formed in the melt with a ratio of Na:K = 1.0 while violet crystals were obtained for a ratio Na:K = 2.0 (Fig. 3). It should be noted that increasing the amount of sodium in the initial melts to a ratio Na/K = 2.0 caused the growth of crystals with sizes of 2–3 mm (Fig. 3b) in length.

Figure 3
Photographs of single crystals of (a) (I) and (b) (II).

The chemical compositions of the prepared samples (quantitative determination of K, Na, Ti, Fe and P) were confirmed by ICP–AES with a Shimadzu ICPE-9820 spectrometer. The analyses showed that the molar ratios of K:Na:Ti:Fe:P were close to 1.65:0.35:1:1:3 for (I) and 1:1:1.25:0.75:3 for (II).

The phosphates (I) and (II) were further characterized using Fourier transform infrared (FTIR) spectroscopy. The spectra were obtained using a PerkinElmer Spectrum BX spectrometer in the range 4000–400 cm⁻¹ (at 4 cm⁻¹ resolution) with sample material pressed into KBr pellets. The FTIR spectra for both compounds are similar in band positions of vibration modes (Fig. 4). The broad and intense bands in the frequency region 1150–900 cm⁻¹ are characteristic for P—O stretching vibrations [ν_as(PO₃) – region 1150–1090 cm⁻¹ and ν_s(PO₃) – region 1020–900 cm⁻¹] of the PO₄ tetrahedron. The band group at 650–550 cm⁻¹ is caused by bending δ(P—O) vibrations of P—O bonds. Some differences in the spectra were observed in the range 500–400 cm⁻¹, which are due to X—O (X = Ti, Fe) vibrations and correlate with insignificant differences in the composition of the prepared compounds (I) and (II).

Figure 4
FTIR spectra of (I) (curve 1) and (II) (curve 2).

4. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3. According to the results of the chemical analysis, large quantities of Na and Ti are present in the structures. Taking into account possible coordination spheres of Na and Ti and previously reported langbeinite-type phosphates with a mixed-metal framework, we supposed that Ti occupies the same sites as Fe, and Na the same positions as K. Hence, the corresponding positions of Fe1 and Fe2, K1 and K2 were occupied with Ti and Na, respectively. As the Fe(Ti) positions are part of the rigid framework, we assumed that these sites show full occupancy, while the sites related with the alkali metal can be fully or partially occupied. At a first approach, the occupancies were refined using linear combinations of free variables (SUMP restraint). Two SUMP restraints were applied to occupancies of Fe1(Ti1) and Fe2(Ti2) sites. One more SUMP restraint was then applied to the sum of valence units of all metal-atom positions. This refinement resulted in satisfactory reliability factors. It was found that the occupancies of K1(Na1) and K2(Na2) are close to 1. Thus, to simplify the refinement we tried to refine the occupancies with free variable constraints instead of SUMP restraints while keeping the alkali metal site occupancies equal to 1. To each refined position, a unique free variable constraint was applied, plus constrained identical coordinates and ADPs for each site. The resulting reliability factors were found to be almost equal to those where the SUMP restraints were used. For the final refinement cycles, the second approach was applied to both structures.

Table 3
Experimental details

	(I)	(II)
Crystal data
Chemical formula	K_1.65Na_0.35TiFe(PO₄)₃	K_0.97Na_1.03Ti_1.26Fe_0.74(PO₄)₃
M_r	461.19	448.16
Crystal system, space group	Cubic, P2₁3	Cubic, P2₁3
Temperature (K)	293	293
a (Å)	9.82010 (13)	9.7945 (1)
V (Å³)	947.00 (4)	939.61 (3)
Z	4	4
Radiation type	Mo Kα	Mo Kα
μ (mm⁻¹)	3.69	3.27
Crystal size (mm)	0.13 × 0.10 × 0.07	0.15 × 0.11 × 0.08

Data collection
Diffractometer	Oxford Diffraction Xcalibur-3	Oxford Diffraction Xcalibur-3
Absorption correction	Multi-scan (Blessing, 1995 )	Multi-scan (Blessing, 1995)
T_min, T_max	0.675, 0.782	0.622, 0.835
No. of measured, independent and observed [I > 2σ(I)] reflections	1897, 847, 829	10546, 837, 833
R_int	0.027	0.026
(sin θ/λ)_max (Å⁻¹)	0.681	0.681

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.025, 0.064, 1.14	0.016, 0.043, 1.12
No. of reflections	847	837
No. of parameters	63	63
Δρ_max, Δρ_min (e Å⁻³)	0.48, −0.37	0.29, −0.27
Absolute structure	Flack x determined using 339 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 )	Flack x determined using 349 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013)
Absolute structure parameter	−0.02 (2)	−0.042 (11)
Computer programs: CrysAlis CCD (Oxford Diffraction, 2006 $[Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]$ ), CrysAlis RED (Oxford Diffraction, 2006 $[Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England.]$ ), SHELXS (Sheldrick, 2008 ), SHELXL (Sheldrick, 2015 ), DIAMOND (Brandenburg, 2006 ), WinGX (Farrugia, 2012 ), enCIFer (Allen et al., 2004 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC references: 2121192; 2121193

Crystal structure: contains datablocks global, I, II. DOI: https://doi.org/10.1107/S2056989021011877/wm5625sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989021011877/wm5625Isup2.hkl

Structure factors: contains datablock II. DOI: https://doi.org/10.1107/S2056989021011877/wm5625IIsup3.hkl

checkCIF report

Computing details top

For both structures, 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: SHELXS (Sheldrick, 2008); program(s) used to refine structure: SHELXL (Sheldrick, 2015); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: WinGX (Farrugia, 2012), enCIFer (Allen et al., 2004) and publCIF (Westrip, 2010).

Potassium sodium titanium iron tris(phosphate) (I) top

Crystal data top

K_1.65Na_0.35TiFe(PO₄)₃	D_x = 3.235 Mg m⁻³
M_r = 461.19	Mo Kα radiation, λ = 0.71073 Å
Cubic, P2₁3	Cell parameters from 1897 reflections
Hall symbol: P 2ac 2ab 3	θ = 2.9–29.0°
a = 9.82010 (13) Å	µ = 3.69 mm⁻¹
V = 947.00 (4) Å³	T = 293 K
Z = 4	Tetrahedron, light yellow
F(000) = 896.8	0.13 × 0.10 × 0.07 mm

Data collection top

Oxford Diffraction Xcalibur-3 diffractometer	829 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.027
φ and ω scans	θ_max = 29.0°, θ_min = 2.9°
Absorption correction: multi-scan (Blessing, 1995)	h = −13→3
T_min = 0.675, T_max = 0.782	k = −5→13
1897 measured reflections	l = −12→12
847 independent reflections

Refinement top

Refinement on F²	'w = 1/[σ²(F_o²) + (0.0292P)² + 0.5767P] where P = (F_o² + 2F_c²)/3'
Least-squares matrix: full	(Δ/σ)_max < 0.001
R[F² > 2σ(F²)] = 0.025	Δρ_max = 0.48 e Å⁻³
wR(F²) = 0.064	Δρ_min = −0.37 e Å⁻³
S = 1.14	Extinction correction: SHELXL-2018/3 (Sheldrick 2015)
847 reflections	Extinction coefficient: 0.0042 (16)
63 parameters	Absolute structure: Flack x determined using 339 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
0 restraints	Absolute structure parameter: 0.02

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)
Fe1	0.14303 (6)	0.14303 (6)	0.14303 (6)	0.0085 (3)	0.52 (3)
Ti1	0.14303 (6)	0.14303 (6)	0.14303 (6)	0.0085 (3)	0.48 (3)
Fe2	0.41389 (6)	0.41389 (6)	0.41389 (6)	0.0087 (3)	0.48 (3)
Ti2	0.41389 (6)	0.41389 (6)	0.41389 (6)	0.0087 (3)	0.52 (3)
K1	0.70712 (13)	0.70712 (13)	0.70712 (13)	0.0254 (7)	0.85 (2)
Na1	0.70712 (13)	0.70712 (13)	0.70712 (13)	0.0254 (7)	0.15 (2)
K2	0.93216 (12)	0.93216 (12)	0.93216 (12)	0.0228 (8)	0.80 (3)
Na2	0.93216 (12)	0.93216 (12)	0.93216 (12)	0.0228 (8)	0.20 (3)
P3	0.45810 (10)	0.22783 (10)	0.12639 (11)	0.0089 (3)
O1	0.3106 (3)	0.2345 (3)	0.0792 (3)	0.0181 (7)
O2	0.5477 (4)	0.2988 (4)	0.0217 (3)	0.0214 (8)
O3	0.5021 (3)	0.0809 (3)	0.1494 (4)	0.0207 (7)
O4	0.4787 (4)	0.3041 (4)	0.2590 (4)	0.0254 (9)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Fe1	0.0085 (3)	0.0085 (3)	0.0085 (3)	−0.0002 (2)	−0.0002 (2)	−0.0002 (2)
Ti1	0.0085 (3)	0.0085 (3)	0.0085 (3)	−0.0002 (2)	−0.0002 (2)	−0.0002 (2)
Fe2	0.0087 (3)	0.0087 (3)	0.0087 (3)	−0.0005 (2)	−0.0005 (2)	−0.0005 (2)
Ti2	0.0087 (3)	0.0087 (3)	0.0087 (3)	−0.0005 (2)	−0.0005 (2)	−0.0005 (2)
K1	0.0254 (7)	0.0254 (7)	0.0254 (7)	0.0004 (5)	0.0004 (5)	0.0004 (5)
Na1	0.0254 (7)	0.0254 (7)	0.0254 (7)	0.0004 (5)	0.0004 (5)	0.0004 (5)
K2	0.0228 (8)	0.0228 (8)	0.0228 (8)	−0.0021 (4)	−0.0021 (4)	−0.0021 (4)
Na2	0.0228 (8)	0.0228 (8)	0.0228 (8)	−0.0021 (4)	−0.0021 (4)	−0.0021 (4)
P3	0.0078 (5)	0.0098 (5)	0.0090 (5)	−0.0003 (3)	0.0014 (4)	0.0001 (4)
O1	0.0103 (14)	0.0218 (16)	0.0222 (17)	−0.0032 (12)	−0.0019 (12)	0.0080 (14)
O2	0.0190 (17)	0.0273 (17)	0.0178 (16)	0.0001 (14)	0.0060 (14)	0.0096 (14)
O3	0.0225 (16)	0.0123 (14)	0.0273 (17)	0.0070 (13)	0.0027 (14)	0.0027 (14)
O4	0.0278 (19)	0.029 (2)	0.0190 (17)	−0.0027 (15)	0.0019 (15)	−0.0148 (15)

Geometric parameters (Å, º) top

Fe1—O2ⁱ	1.954 (3)	K1—O2^xviii	3.019 (4)
Fe1—O2ⁱⁱ	1.954 (3)	K1—O4^xvi	3.129 (4)
Fe1—O2ⁱⁱⁱ	1.954 (3)	K1—O4^xvii	3.129 (4)
Fe1—O1	1.976 (3)	K1—O4^xviii	3.129 (4)
Fe1—O1^iv	1.976 (3)	K1—P3^xvi	3.4416 (16)
Fe1—O1^v	1.976 (3)	K1—P3^xviii	3.4416 (16)
Fe1—K2^vi	3.587 (2)	K1—P3^xvii	3.4416 (16)
Fe1—K1^vii	3.7927 (9)	K2—O3^xvi	2.854 (4)
Fe1—K1^viii	3.7927 (9)	K2—O3^xvii	2.854 (4)
Fe1—K1^ix	3.7927 (9)	K2—O3^xviii	2.854 (4)
Fe2—O3^x	1.938 (3)	K2—O2^xix	2.911 (4)
Fe2—O3^xi	1.938 (3)	K2—O2^xx	2.911 (4)
Fe2—O3^xii	1.938 (3)	K2—O2^xxi	2.911 (4)
Fe2—O4^v	1.970 (3)	K2—O4^xvii	3.007 (4)
Fe2—O4^iv	1.970 (3)	K2—O4^xvi	3.007 (4)
Fe2—O4	1.970 (3)	K2—O4^xviii	3.007 (4)
Fe2—K2^xiii	3.7237 (7)	K2—O4^xx	3.231 (4)
Fe2—K2^xiv	3.7237 (7)	K2—O4^xxi	3.231 (4)
Fe2—K2^xv	3.7237 (7)	K2—O4^xix	3.231 (4)
K1—O1^xii	2.830 (4)	P3—O4	1.516 (4)
K1—O1^x	2.830 (4)	P3—O2	1.522 (3)
K1—O1^xi	2.830 (4)	P3—O3	1.523 (3)
K1—O2^xvi	3.019 (4)	P3—O1	1.523 (3)
K1—O2^xvii	3.019 (4)

O2ⁱ—Fe1—O2ⁱⁱ	89.19 (16)	O4^xvi—K1—P3^xviii	69.72 (7)
O2ⁱ—Fe1—O2ⁱⁱⁱ	89.19 (16)	O4^xvii—K1—P3^xviii	103.33 (10)
O2ⁱⁱ—Fe1—O2ⁱⁱⁱ	89.19 (16)	O4^xviii—K1—P3^xviii	26.12 (7)
O2ⁱ—Fe1—O1	177.99 (16)	P3^xvi—K1—P3^xviii	94.91 (5)
O2ⁱⁱ—Fe1—O1	88.89 (15)	O1^xii—K1—P3^xvii	94.57 (7)
O2ⁱⁱⁱ—Fe1—O1	90.18 (14)	O1^x—K1—P3^xvii	79.17 (7)
O2ⁱ—Fe1—O1^iv	88.88 (15)	O1^xi—K1—P3^xvii	169.22 (7)
O2ⁱⁱ—Fe1—O1^iv	90.18 (14)	O2^xvi—K1—P3^xvii	108.29 (8)
O2ⁱⁱⁱ—Fe1—O1^iv	177.99 (16)	O2^xvii—K1—P3^xvii	26.23 (6)
O1—Fe1—O1^iv	91.72 (14)	O2^xviii—K1—P3^xvii	115.08 (8)
O2ⁱ—Fe1—O1^v	90.18 (14)	O4^xvi—K1—P3^xvii	103.33 (10)
O2ⁱⁱ—Fe1—O1^v	177.99 (16)	O4^xvii—K1—P3^xvii	26.12 (7)
O2ⁱⁱⁱ—Fe1—O1^v	88.88 (15)	O4^xviii—K1—P3^xvii	69.72 (7)
O1—Fe1—O1^v	91.71 (14)	P3^xvi—K1—P3^xvii	94.91 (5)
O1^iv—Fe1—O1^v	91.72 (14)	P3^xviii—K1—P3^xvii	94.91 (5)
O2ⁱ—Fe1—K2^vi	54.17 (11)	O3^xvi—K2—O3^xvii	100.76 (10)
O2ⁱⁱ—Fe1—K2^vi	54.17 (11)	O3^xvi—K2—O3^xviii	100.76 (10)
O2ⁱⁱⁱ—Fe1—K2^vi	54.17 (11)	O3^xvii—K2—O3^xviii	100.76 (10)
O1—Fe1—K2^vi	124.04 (10)	O3^xvi—K2—O2^xix	100.42 (10)
O1^iv—Fe1—K2^vi	124.04 (10)	O3^xvii—K2—O2^xix	149.92 (11)
O1^v—Fe1—K2^vi	124.04 (10)	O3^xviii—K2—O2^xix	95.97 (10)
O2ⁱ—Fe1—K1^vii	52.19 (11)	O3^xvi—K2—O2^xx	95.97 (10)
O2ⁱⁱ—Fe1—K1^vii	131.75 (12)	O3^xvii—K2—O2^xx	100.42 (10)
O2ⁱⁱⁱ—Fe1—K1^vii	65.77 (11)	O3^xviii—K2—O2^xx	149.92 (11)
O1—Fe1—K1^vii	129.13 (11)	O2^xix—K2—O2^xx	56.22 (11)
O1^iv—Fe1—K1^vii	113.38 (10)	O3^xvi—K2—O2^xxi	149.92 (11)
O1^v—Fe1—K1^vii	46.69 (10)	O3^xvii—K2—O2^xxi	95.97 (10)
K2^vi—Fe1—K1^vii	78.252 (17)	O3^xviii—K2—O2^xxi	100.42 (10)
O2ⁱ—Fe1—K1^viii	65.77 (11)	O2^xix—K2—O2^xxi	56.22 (11)
O2ⁱⁱ—Fe1—K1^viii	52.19 (11)	O2^xx—K2—O2^xxi	56.22 (11)
O2ⁱⁱⁱ—Fe1—K1^viii	131.75 (12)	O3^xvi—K2—O4^xvii	52.44 (10)
O1—Fe1—K1^viii	113.38 (10)	O3^xvii—K2—O4^xvii	49.39 (9)
O1^iv—Fe1—K1^viii	46.69 (10)	O3^xviii—K2—O4^xvii	115.63 (12)
O1^v—Fe1—K1^viii	129.13 (11)	O2^xix—K2—O4^xvii	140.25 (11)
K2^vi—Fe1—K1^viii	78.252 (17)	O2^xx—K2—O4^xvii	94.39 (10)
K1^vii—Fe1—K1^viii	115.965 (12)	O2^xxi—K2—O4^xvii	132.45 (10)
O2ⁱ—Fe1—K1^ix	131.75 (12)	O3^xvi—K2—O4^xvi	49.39 (9)
O2ⁱⁱ—Fe1—K1^ix	65.77 (11)	O3^xvii—K2—O4^xvi	115.63 (12)
O2ⁱⁱⁱ—Fe1—K1^ix	52.19 (11)	O3^xviii—K2—O4^xvi	52.44 (10)
O1—Fe1—K1^ix	46.69 (10)	O2^xix—K2—O4^xvi	94.39 (10)
O1^iv—Fe1—K1^ix	129.13 (11)	O2^xx—K2—O4^xvi	132.45 (10)
O1^v—Fe1—K1^ix	113.38 (10)	O2^xxi—K2—O4^xvi	140.25 (11)
K2^vi—Fe1—K1^ix	78.252 (17)	O4^xvii—K2—O4^xvi	87.30 (11)
K1^vii—Fe1—K1^ix	115.965 (12)	O3^xvi—K2—O4^xviii	115.63 (12)
K1^viii—Fe1—K1^ix	115.965 (12)	O3^xvii—K2—O4^xviii	52.44 (10)
O3^x—Fe2—O3^xi	92.72 (15)	O3^xviii—K2—O4^xviii	49.39 (9)
O3^x—Fe2—O3^xii	92.72 (15)	O2^xix—K2—O4^xviii	132.45 (10)
O3^xi—Fe2—O3^xii	92.72 (15)	O2^xx—K2—O4^xviii	140.25 (11)
O3^x—Fe2—O4^v	171.85 (17)	O2^xxi—K2—O4^xviii	94.39 (10)
O3^xi—Fe2—O4^v	83.11 (16)	O4^xvii—K2—O4^xviii	87.30 (11)
O3^xii—Fe2—O4^v	94.47 (15)	O4^xvi—K2—O4^xviii	87.30 (11)
O3^x—Fe2—O4^iv	94.47 (15)	O3^xvi—K2—O4^xx	55.86 (9)
O3^xi—Fe2—O4^iv	171.85 (17)	O3^xvii—K2—O4^xx	85.99 (9)
O3^xii—Fe2—O4^iv	83.11 (16)	O3^xviii—K2—O4^xx	156.61 (10)
O4^v—Fe2—O4^iv	90.22 (16)	O2^xix—K2—O4^xx	88.46 (10)
O3^x—Fe2—O4	83.11 (16)	O2^xx—K2—O4^xx	46.20 (9)
O3^xi—Fe2—O4	94.47 (15)	O2^xxi—K2—O4^xx	101.11 (10)
O3^xii—Fe2—O4	171.85 (17)	O4^xvii—K2—O4^xx	53.02 (13)
O4^v—Fe2—O4	90.22 (16)	O4^xvi—K2—O4^xx	104.40 (2)
O4^iv—Fe2—O4	90.22 (16)	O4^xviii—K2—O4^xx	137.03 (8)
O3^x—Fe2—K2^xiii	127.93 (11)	O3^xvi—K2—O4^xxi	156.61 (10)
O3^xi—Fe2—K2^xiii	118.56 (11)	O3^xvii—K2—O4^xxi	55.86 (9)
O3^xii—Fe2—K2^xiii	48.96 (11)	O3^xviii—K2—O4^xxi	85.99 (9)
O4^v—Fe2—K2^xiii	60.13 (13)	O2^xix—K2—O4^xxi	101.11 (10)
O4^iv—Fe2—K2^xiii	53.60 (12)	O2^xx—K2—O4^xxi	88.46 (10)
O4—Fe2—K2^xiii	129.40 (12)	O2^xxi—K2—O4^xxi	46.20 (9)
O3^x—Fe2—K2^xiv	118.56 (11)	O4^xvii—K2—O4^xxi	104.40 (2)
O3^xi—Fe2—K2^xiv	48.96 (11)	O4^xvi—K2—O4^xxi	137.03 (8)
O3^xii—Fe2—K2^xiv	127.93 (11)	O4^xviii—K2—O4^xxi	53.02 (13)
O4^v—Fe2—K2^xiv	53.60 (12)	O4^xx—K2—O4^xxi	115.75 (5)
O4^iv—Fe2—K2^xiv	129.40 (12)	O3^xvi—K2—O4^xix	85.99 (9)
O4—Fe2—K2^xiv	60.13 (12)	O3^xvii—K2—O4^xix	156.61 (10)
K2^xiii—Fe2—K2^xiv	113.261 (15)	O3^xviii—K2—O4^xix	55.86 (9)
O3^x—Fe2—K2^xv	48.96 (11)	O2^xix—K2—O4^xix	46.20 (9)
O3^xi—Fe2—K2^xv	127.93 (11)	O2^xx—K2—O4^xix	101.11 (10)
O3^xii—Fe2—K2^xv	118.56 (11)	O2^xxi—K2—O4^xix	88.46 (10)
O4^v—Fe2—K2^xv	129.40 (12)	O4^xvii—K2—O4^xix	137.03 (8)
O4^iv—Fe2—K2^xv	60.13 (12)	O4^xvi—K2—O4^xix	53.02 (13)
O4—Fe2—K2^xv	53.60 (12)	O4^xviii—K2—O4^xix	104.40 (2)
K2^xiii—Fe2—K2^xv	113.261 (15)	O4^xx—K2—O4^xix	115.75 (5)
K2^xiv—Fe2—K2^xv	113.261 (15)	O4^xxi—K2—O4^xix	115.75 (5)
O1^xii—K1—O1^x	92.24 (11)	O4—P3—O2	106.1 (2)
O1^xii—K1—O1^xi	92.24 (12)	O4—P3—O3	107.6 (2)
O1^x—K1—O1^xi	92.24 (11)	O2—P3—O3	111.7 (2)
O1^xii—K1—O2^xvi	56.73 (9)	O4—P3—O1	111.6 (2)
O1^x—K1—O2^xvi	148.02 (12)	O2—P3—O1	109.0 (2)
O1^xi—K1—O2^xvi	82.44 (10)	O3—P3—O1	110.81 (19)
O1^xii—K1—O2^xvii	82.44 (10)	O4—P3—K2^xiv	70.72 (16)
O1^x—K1—O2^xvii	56.73 (9)	O2—P3—K2^xiv	58.63 (14)
O1^xi—K1—O2^xvii	148.02 (12)	O3—P3—K2^xiv	167.81 (14)
O2^xvi—K1—O2^xvii	118.99 (3)	O1—P3—K2^xiv	80.51 (13)
O1^xii—K1—O2^xviii	148.02 (12)	O4—P3—K1^xv	65.34 (15)
O1^x—K1—O2^xviii	82.44 (10)	O2—P3—K1^xv	61.21 (14)
O1^xi—K1—O2^xviii	56.73 (9)	O3—P3—K1^xv	82.59 (14)
O2^xvi—K1—O2^xviii	118.99 (3)	O1—P3—K1^xv	166.21 (14)
O2^xvii—K1—O2^xviii	118.99 (3)	K2^xiv—P3—K1^xv	85.88 (3)
O1^xii—K1—O4^xvi	103.04 (9)	O4—P3—K2^xv	56.80 (16)
O1^x—K1—O4^xvi	164.18 (10)	O2—P3—K2^xv	126.68 (15)
O1^xi—K1—O4^xvi	83.19 (10)	O3—P3—K2^xv	50.98 (15)
O2^xvi—K1—O4^xvi	46.48 (9)	O1—P3—K2^xv	124.35 (14)
O2^xvii—K1—O4^xvi	128.76 (12)	K2^xiv—P3—K2^xv	126.85 (4)
O2^xviii—K1—O4^xvi	82.41 (10)	K1^xv—P3—K2^xv	66.30 (5)
O1^xii—K1—O4^xvii	83.19 (10)	O4—P3—K1^ix	148.79 (17)
O1^x—K1—O4^xvii	103.04 (9)	O2—P3—K1^ix	71.17 (14)
O1^xi—K1—O4^xvii	164.18 (10)	O3—P3—K1^ix	101.86 (15)
O2^xvi—K1—O4^xvii	82.41 (10)	O1—P3—K1^ix	46.23 (13)
O2^xvii—K1—O4^xvii	46.48 (9)	K2^xiv—P3—K1^ix	82.53 (3)
O2^xviii—K1—O4^xvii	128.76 (12)	K1^xv—P3—K1^ix	129.78 (5)
O4^xvi—K1—O4^xvii	83.10 (12)	K2^xv—P3—K1^ix	149.91 (4)
O1^xii—K1—O4^xviii	164.18 (10)	P3—O1—Fe1	132.5 (2)
O1^x—K1—O4^xviii	83.19 (10)	P3—O1—K1^ix	110.90 (17)
O1^xi—K1—O4^xviii	103.04 (9)	Fe1—O1—K1^ix	102.77 (13)
O2^xvi—K1—O4^xviii	128.76 (12)	P3—O2—Fe1^xxii	165.9 (2)
O2^xvii—K1—O4^xviii	82.41 (10)	P3—O2—K2^xiv	94.85 (16)
O2^xviii—K1—O4^xviii	46.48 (9)	Fe1^xxii—O2—K2^xiv	92.87 (13)
O4^xvi—K1—O4^xviii	83.10 (12)	P3—O2—K1^xv	92.56 (16)
O4^xvii—K1—O4^xviii	83.10 (12)	Fe1^xxii—O2—K1^xv	97.07 (13)
O1^xii—K1—P3^xvi	79.17 (7)	K2^xiv—O2—K1^xv	103.55 (11)
O1^x—K1—P3^xvi	169.22 (7)	P3—O3—Fe2^ix	151.0 (2)
O1^xi—K1—P3^xvi	94.57 (7)	P3—O3—K2^xv	104.53 (18)
O2^xvi—K1—P3^xvi	26.23 (6)	Fe2^ix—O3—K2^xv	100.23 (13)
O2^xvii—K1—P3^xvi	115.08 (8)	P3—O4—Fe2	152.9 (3)
O2^xviii—K1—P3^xvi	108.29 (8)	P3—O4—K2^xv	98.25 (18)
O4^xvi—K1—P3^xvi	26.12 (7)	Fe2—O4—K2^xv	94.57 (14)
O4^xvii—K1—P3^xvi	69.72 (7)	P3—O4—K1^xv	88.54 (16)
O4^xviii—K1—P3^xvi	103.33 (10)	Fe2—O4—K1^xv	117.62 (15)
O1^xii—K1—P3^xviii	169.22 (7)	K2^xv—O4—K1^xv	77.17 (10)
O1^x—K1—P3^xviii	94.57 (7)	P3—O4—K2^xiv	83.00 (16)
O1^xi—K1—P3^xviii	79.17 (7)	Fe2—O4—K2^xiv	87.94 (14)
O2^xvi—K1—P3^xviii	115.08 (8)	K2^xv—O4—K2^xiv	171.21 (14)
O2^xvii—K1—P3^xviii	108.29 (8)	K1^xv—O4—K2^xiv	94.20 (11)
O2^xviii—K1—P3^xviii	26.23 (6)

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

Potassium sodium titanium iron tris(phosphate) (II) top

Crystal data top

K_0.97Na_1.03Ti_1.26Fe_0.74(PO₄)₃	D_x = 3.168 Mg m⁻³
M_r = 448.16	Mo Kα radiation, λ = 0.71073 Å
Cubic, P2₁3	Cell parameters from 10546 reflections
Hall symbol: P 2ac 2ab 3	θ = 2.9–29.0°
a = 9.7945 (1) Å	µ = 3.27 mm⁻¹
V = 939.61 (3) Å³	T = 293 K
Z = 4	Tetrahedron, violet
F(000) = 870.9	0.15 × 0.11 × 0.08 mm

Data collection top

Oxford Diffraction Xcalibur-3 diffractometer	833 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.026
φ and ω scans	θ_max = 29.0°, θ_min = 2.9°
Absorption correction: multi-scan (Blessing, 1995)	h = −12→13
T_min = 0.622, T_max = 0.835	k = −13→13
10546 measured reflections	l = −13→13
837 independent reflections

Refinement top

Refinement on F²	'w = 1/[σ²(F_o²) + (0.0186P)² + 1.1348P] where P = (F_o² + 2F_c²)/3'
Least-squares matrix: full	(Δ/σ)_max < 0.001
R[F² > 2σ(F²)] = 0.016	Δρ_max = 0.28 e Å⁻³
wR(F²) = 0.043	Δρ_min = −0.27 e Å⁻³
S = 1.12	Extinction correction: SHELXL-2018/3 (Sheldrick 2015)
837 reflections	Extinction coefficient: 0.0015 (10)
63 parameters	Absolute structure: Flack x determined using 349 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
0 restraints	Absolute structure parameter: 0.02

Special details top

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
Fe1	0.14198 (4)	0.14198 (4)	0.14198 (4)	0.0079 (2)	0.39 (2)
Ti1	0.14198 (4)	0.14198 (4)	0.14198 (4)	0.0079 (2)	0.61 (2)
Fe2	0.41334 (4)	0.41334 (4)	0.41334 (4)	0.0079 (2)	0.35 (2)
Ti2	0.41334 (4)	0.41334 (4)	0.41334 (4)	0.0079 (2)	0.65 (2)
K1	0.70732 (10)	0.70732 (10)	0.70732 (10)	0.0266 (6)	0.676 (18)
Na1	0.70732 (10)	0.70732 (10)	0.70732 (10)	0.0266 (6)	0.324 (18)
K2	0.93159 (11)	0.93159 (11)	0.93159 (11)	0.0254 (8)	0.294 (19)
Na2	0.93159 (11)	0.93159 (11)	0.93159 (11)	0.0254 (8)	0.706 (19)
P3	0.45787 (7)	0.22778 (7)	0.12657 (7)	0.00815 (19)
O1	0.3100 (2)	0.2337 (3)	0.0789 (2)	0.0210 (5)
O2	0.5478 (3)	0.2989 (3)	0.0220 (3)	0.0266 (6)
O3	0.5024 (3)	0.0810 (2)	0.1492 (3)	0.0269 (5)
O4	0.4786 (3)	0.3034 (3)	0.2602 (3)	0.0313 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Fe1	0.0079 (2)	0.0079 (2)	0.0079 (2)	0.00028 (15)	0.00028 (15)	0.00028 (15)
Ti1	0.0079 (2)	0.0079 (2)	0.0079 (2)	0.00028 (15)	0.00028 (15)	0.00028 (15)
Fe2	0.0079 (2)	0.0079 (2)	0.0079 (2)	−0.00052 (15)	−0.00052 (15)	−0.00052 (15)
Ti2	0.0079 (2)	0.0079 (2)	0.0079 (2)	−0.00052 (15)	−0.00052 (15)	−0.00052 (15)
K1	0.0266 (6)	0.0266 (6)	0.0266 (6)	0.0015 (4)	0.0015 (4)	0.0015 (4)
Na1	0.0266 (6)	0.0266 (6)	0.0266 (6)	0.0015 (4)	0.0015 (4)	0.0015 (4)
K2	0.0254 (8)	0.0254 (8)	0.0254 (8)	−0.0021 (4)	−0.0021 (4)	−0.0021 (4)
Na2	0.0254 (8)	0.0254 (8)	0.0254 (8)	−0.0021 (4)	−0.0021 (4)	−0.0021 (4)
P3	0.0075 (3)	0.0087 (3)	0.0083 (3)	−0.0003 (2)	0.0015 (2)	−0.0007 (2)
O1	0.0088 (9)	0.0299 (12)	0.0242 (12)	−0.0033 (8)	−0.0020 (8)	0.0089 (10)
O2	0.0197 (11)	0.0361 (14)	0.0241 (12)	−0.0014 (10)	0.0088 (10)	0.0136 (11)
O3	0.0263 (12)	0.0128 (10)	0.0415 (14)	0.0088 (9)	0.0053 (11)	0.0032 (11)
O4	0.0333 (14)	0.0373 (15)	0.0232 (12)	−0.0027 (12)	0.0014 (11)	−0.0206 (11)

Geometric parameters (Å, º) top

Fe1—O2ⁱ	1.940 (2)	K1—O2^xviii	3.009 (3)
Fe1—O2ⁱⁱ	1.940 (2)	K1—O4^xvii	3.122 (3)
Fe1—O2ⁱⁱⁱ	1.940 (2)	K1—O4^xviii	3.122 (3)
Fe1—O1	1.974 (2)	K1—O4^xvi	3.122 (3)
Fe1—O1^iv	1.974 (2)	K1—P3^xviii	3.4327 (11)
Fe1—O1^v	1.974 (2)	K1—P3^xvii	3.4327 (11)
Fe1—K2^vi	3.569 (2)	K1—P3^xvi	3.4327 (11)
Fe1—K1^vii	3.7806 (7)	K2—O3^xvii	2.843 (3)
Fe1—K1^viii	3.7806 (7)	K2—O3^xvi	2.843 (3)
Fe1—K1^ix	3.7806 (7)	K2—O3^xviii	2.843 (3)
Fe2—O3^x	1.938 (2)	K2—O2^xix	2.910 (3)
Fe2—O3^xi	1.938 (2)	K2—O2^xx	2.910 (3)
Fe2—O3^xii	1.938 (2)	K2—O2^xxi	2.910 (3)
Fe2—O4	1.954 (2)	K2—O4^xvii	2.982 (4)
Fe2—O4^iv	1.954 (2)	K2—O4^xvi	2.982 (4)
Fe2—O4^v	1.954 (2)	K2—O4^xviii	2.982 (4)
Fe2—K2^xiii	3.7084 (6)	K2—O4^xx	3.237 (3)
Fe2—K2^xiv	3.7084 (6)	K2—O4^xix	3.237 (3)
Fe2—K2^xv	3.7084 (6)	K2—O4^xxi	3.237 (3)
K1—O1^xi	2.820 (3)	P3—O4	1.517 (3)
K1—O1^xii	2.820 (3)	P3—O3	1.518 (2)
K1—O1^x	2.820 (3)	P3—O2	1.520 (2)
K1—O2^xvi	3.009 (3)	P3—O1	1.523 (2)
K1—O2^xvii	3.009 (3)

O2ⁱ—Fe1—O2ⁱⁱ	89.72 (12)	O4^xvii—K1—P3^xvii	26.22 (5)
O2ⁱ—Fe1—O2ⁱⁱⁱ	89.72 (12)	O4^xviii—K1—P3^xvii	103.21 (8)
O2ⁱⁱ—Fe1—O2ⁱⁱⁱ	89.72 (12)	O4^xvi—K1—P3^xvii	69.59 (5)
O2ⁱ—Fe1—O1	178.52 (12)	P3^xviii—K1—P3^xvii	94.92 (4)
O2ⁱⁱ—Fe1—O1	88.81 (11)	O1^xi—K1—P3^xvi	94.74 (5)
O2ⁱⁱⁱ—Fe1—O1	90.09 (10)	O1^xii—K1—P3^xvi	79.13 (5)
O2ⁱ—Fe1—O1^iv	90.09 (10)	O1^x—K1—P3^xvi	169.06 (5)
O2ⁱⁱ—Fe1—O1^iv	178.52 (12)	O2^xvi—K1—P3^xvi	26.25 (5)
O2ⁱⁱⁱ—Fe1—O1^iv	88.81 (11)	O2^xvii—K1—P3^xvi	108.35 (6)
O1—Fe1—O1^iv	91.38 (10)	O2^xviii—K1—P3^xvi	115.09 (6)
O2ⁱ—Fe1—O1^v	88.81 (11)	O4^xvii—K1—P3^xvi	103.21 (8)
O2ⁱⁱ—Fe1—O1^v	90.09 (10)	O4^xviii—K1—P3^xvi	69.59 (5)
O2ⁱⁱⁱ—Fe1—O1^v	178.52 (12)	O4^xvi—K1—P3^xvi	26.22 (5)
O1—Fe1—O1^v	91.38 (10)	P3^xviii—K1—P3^xvi	94.92 (4)
O1^iv—Fe1—O1^v	91.38 (10)	P3^xvii—K1—P3^xvi	94.92 (4)
O2ⁱ—Fe1—K2^vi	54.54 (9)	O3^xvii—K2—O3^xvi	100.89 (8)
O2ⁱⁱ—Fe1—K2^vi	54.54 (9)	O3^xvii—K2—O3^xviii	100.89 (8)
O2ⁱⁱⁱ—Fe1—K2^vi	54.54 (9)	O3^xvi—K2—O3^xviii	100.89 (8)
O1—Fe1—K2^vi	124.28 (7)	O3^xvii—K2—O2^xix	149.75 (9)
O1^iv—Fe1—K2^vi	124.28 (7)	O3^xvi—K2—O2^xix	95.89 (7)
O1^v—Fe1—K2^vi	124.28 (7)	O3^xviii—K2—O2^xix	100.42 (8)
O2ⁱ—Fe1—K1^vii	132.34 (9)	O3^xvii—K2—O2^xx	95.89 (7)
O2ⁱⁱ—Fe1—K1^vii	66.00 (8)	O3^xvi—K2—O2^xx	100.42 (8)
O2ⁱⁱⁱ—Fe1—K1^vii	52.14 (8)	O3^xviii—K2—O2^xx	149.75 (9)
O1—Fe1—K1^vii	46.70 (7)	O2^xix—K2—O2^xx	56.11 (8)
O1^iv—Fe1—K1^vii	113.14 (8)	O3^xvii—K2—O2^xxi	100.42 (8)
O1^v—Fe1—K1^vii	129.02 (8)	O3^xvi—K2—O2^xxi	149.75 (9)
K2^vi—Fe1—K1^vii	78.502 (13)	O3^xviii—K2—O2^xxi	95.89 (7)
O2ⁱ—Fe1—K1^viii	66.00 (8)	O2^xix—K2—O2^xxi	56.11 (8)
O2ⁱⁱ—Fe1—K1^viii	52.14 (8)	O2^xx—K2—O2^xxi	56.11 (8)
O2ⁱⁱⁱ—Fe1—K1^viii	132.34 (9)	O3^xvii—K2—O4^xvii	49.57 (7)
O1—Fe1—K1^viii	113.14 (8)	O3^xvi—K2—O4^xvii	115.99 (10)
O1^iv—Fe1—K1^viii	129.02 (8)	O3^xviii—K2—O4^xvii	52.41 (7)
O1^v—Fe1—K1^viii	46.70 (7)	O2^xix—K2—O4^xvii	140.03 (8)
K2^vi—Fe1—K1^viii	78.502 (13)	O2^xx—K2—O4^xvii	132.27 (7)
K1^vii—Fe1—K1^viii	116.129 (8)	O2^xxi—K2—O4^xvii	94.19 (7)
O2ⁱ—Fe1—K1^ix	52.14 (8)	O3^xvii—K2—O4^xvi	52.41 (7)
O2ⁱⁱ—Fe1—K1^ix	132.34 (9)	O3^xvi—K2—O4^xvi	49.57 (7)
O2ⁱⁱⁱ—Fe1—K1^ix	66.00 (8)	O3^xviii—K2—O4^xvi	115.99 (10)
O1—Fe1—K1^ix	129.02 (8)	O2^xix—K2—O4^xvi	132.27 (7)
O1^iv—Fe1—K1^ix	46.70 (7)	O2^xx—K2—O4^xvi	94.19 (7)
O1^v—Fe1—K1^ix	113.14 (8)	O2^xxi—K2—O4^xvi	140.03 (8)
K2^vi—Fe1—K1^ix	78.502 (13)	O4^xvii—K2—O4^xvi	87.67 (9)
K1^vii—Fe1—K1^ix	116.129 (8)	O3^xvii—K2—O4^xviii	115.99 (10)
K1^viii—Fe1—K1^ix	116.129 (8)	O3^xvi—K2—O4^xviii	52.41 (7)
O3^x—Fe2—O3^xi	92.37 (12)	O3^xviii—K2—O4^xviii	49.57 (7)
O3^x—Fe2—O3^xii	92.37 (12)	O2^xix—K2—O4^xviii	94.19 (7)
O3^xi—Fe2—O3^xii	92.37 (12)	O2^xx—K2—O4^xviii	140.03 (8)
O3^x—Fe2—O4	94.89 (12)	O2^xxi—K2—O4^xviii	132.27 (8)
O3^xi—Fe2—O4	171.47 (13)	O4^xvii—K2—O4^xviii	87.67 (9)
O3^xii—Fe2—O4	82.87 (13)	O4^xvi—K2—O4^xviii	87.67 (9)
O3^x—Fe2—O4^iv	82.87 (13)	O3^xvii—K2—O4^xx	55.81 (6)
O3^xi—Fe2—O4^iv	94.90 (12)	O3^xvi—K2—O4^xx	86.02 (7)
O3^xii—Fe2—O4^iv	171.46 (13)	O3^xviii—K2—O4^xx	156.68 (8)
O4—Fe2—O4^iv	90.46 (12)	O2^xix—K2—O4^xx	100.98 (8)
O3^x—Fe2—O4^v	171.46 (13)	O2^xx—K2—O4^xx	46.19 (7)
O3^xi—Fe2—O4^v	82.87 (13)	O2^xxi—K2—O4^xx	88.43 (8)
O3^xii—Fe2—O4^v	94.90 (12)	O4^xvii—K2—O4^xx	104.497 (19)
O4—Fe2—O4^v	90.46 (12)	O4^xvi—K2—O4^xx	52.80 (10)
O4^iv—Fe2—O4^v	90.46 (12)	O4^xviii—K2—O4^xx	137.10 (6)
O3^x—Fe2—K2^xiii	118.47 (8)	O3^xvii—K2—O4^xix	156.68 (8)
O3^xi—Fe2—K2^xiii	49.04 (9)	O3^xvi—K2—O4^xix	55.81 (6)
O3^xii—Fe2—K2^xiii	127.81 (8)	O3^xviii—K2—O4^xix	86.02 (7)
O4—Fe2—K2^xiii	129.70 (9)	O2^xix—K2—O4^xix	46.19 (7)
O4^iv—Fe2—K2^xiii	60.69 (10)	O2^xx—K2—O4^xix	88.43 (8)
O4^v—Fe2—K2^xiii	53.21 (10)	O2^xxi—K2—O4^xix	100.98 (8)
O3^x—Fe2—K2^xiv	127.81 (8)	O4^xvii—K2—O4^xix	137.10 (6)
O3^xi—Fe2—K2^xiv	118.47 (8)	O4^xvi—K2—O4^xix	104.497 (19)
O3^xii—Fe2—K2^xiv	49.04 (9)	O4^xviii—K2—O4^xix	52.80 (10)
O4—Fe2—K2^xiv	53.21 (10)	O4^xx—K2—O4^xix	115.71 (4)
O4^iv—Fe2—K2^xiv	129.70 (9)	O3^xvii—K2—O4^xxi	86.02 (7)
O4^v—Fe2—K2^xiv	60.69 (10)	O3^xvi—K2—O4^xxi	156.68 (8)
K2^xiii—Fe2—K2^xiv	113.409 (11)	O3^xviii—K2—O4^xxi	55.81 (6)
O3^x—Fe2—K2^xv	49.04 (9)	O2^xix—K2—O4^xxi	88.43 (8)
O3^xi—Fe2—K2^xv	127.81 (8)	O2^xx—K2—O4^xxi	100.98 (8)
O3^xii—Fe2—K2^xv	118.47 (8)	O2^xxi—K2—O4^xxi	46.19 (7)
O4—Fe2—K2^xv	60.69 (10)	O4^xvii—K2—O4^xxi	52.80 (10)
O4^iv—Fe2—K2^xv	53.21 (10)	O4^xvi—K2—O4^xxi	137.10 (6)
O4^v—Fe2—K2^xv	129.70 (9)	O4^xviii—K2—O4^xxi	104.497 (19)
K2^xiii—Fe2—K2^xv	113.409 (11)	O4^xx—K2—O4^xxi	115.71 (4)
K2^xiv—Fe2—K2^xv	113.409 (11)	O4^xix—K2—O4^xxi	115.71 (4)
O1^xi—K1—O1^xii	92.11 (9)	O4—P3—O3	107.34 (18)
O1^xi—K1—O1^x	92.11 (9)	O4—P3—O2	106.27 (16)
O1^xii—K1—O1^x	92.11 (9)	O3—P3—O2	111.46 (16)
O1^xi—K1—O2^xvi	82.55 (7)	O4—P3—O1	111.89 (15)
O1^xii—K1—O2^xvi	56.64 (6)	O3—P3—O1	110.74 (14)
O1^x—K1—O2^xvi	147.84 (9)	O2—P3—O1	109.06 (14)
O1^xi—K1—O2^xvii	56.64 (6)	O4—P3—K2^xv	71.04 (13)
O1^xii—K1—O2^xvii	147.84 (9)	O3—P3—K2^xv	167.62 (11)
O1^x—K1—O2^xvii	82.55 (7)	O2—P3—K2^xv	58.68 (11)
O2^xvi—K1—O2^xvii	119.008 (19)	O1—P3—K2^xv	80.72 (10)
O1^xi—K1—O2^xviii	147.84 (9)	O4—P3—K1^xiv	65.37 (11)
O1^xii—K1—O2^xviii	82.55 (7)	O3—P3—K1^xiv	82.38 (11)
O1^x—K1—O2^xviii	56.64 (6)	O2—P3—K1^xiv	61.12 (11)
O2^xvi—K1—O2^xviii	119.008 (19)	O1—P3—K1^xiv	166.43 (11)
O2^xvii—K1—O2^xviii	119.008 (19)	K2^xv—P3—K1^xiv	85.93 (3)
O1^xi—K1—O4^xvii	103.13 (7)	O4—P3—K2^xiv	56.40 (13)
O1^xii—K1—O4^xvii	164.24 (7)	O3—P3—K2^xiv	51.08 (12)
O1^x—K1—O4^xvii	83.46 (8)	O2—P3—K2^xiv	126.42 (11)
O2^xvi—K1—O4^xvii	128.67 (9)	O1—P3—K2^xiv	124.51 (10)
O2^xvii—K1—O4^xvii	46.65 (7)	K2^xv—P3—K2^xiv	126.74 (3)
O2^xviii—K1—O4^xvii	82.39 (7)	K1^xiv—P3—K2^xiv	66.11 (4)
O1^xi—K1—O4^xviii	164.24 (7)	O4—P3—K1^vii	149.07 (13)
O1^xii—K1—O4^xviii	83.46 (8)	O3—P3—K1^vii	101.87 (12)
O1^x—K1—O4^xviii	103.13 (7)	O2—P3—K1^vii	71.24 (11)
O2^xvi—K1—O4^xviii	82.39 (7)	O1—P3—K1^vii	46.09 (9)
O2^xvii—K1—O4^xviii	128.67 (9)	K2^xv—P3—K1^vii	82.54 (3)
O2^xviii—K1—O4^xviii	46.65 (7)	K1^xiv—P3—K1^vii	129.74 (3)
O4^xvii—K1—O4^xviii	82.84 (10)	K2^xiv—P3—K1^vii	150.05 (3)
O1^xi—K1—O4^xvi	83.46 (8)	P3—O1—Fe1	132.78 (15)
O1^xii—K1—O4^xvi	103.13 (7)	P3—O1—K1^vii	111.02 (12)
O1^x—K1—O4^xvi	164.24 (7)	Fe1—O1—K1^vii	102.66 (9)
O2^xvi—K1—O4^xvi	46.65 (7)	P3—O2—Fe1^xxii	165.93 (19)
O2^xvii—K1—O4^xvi	82.39 (7)	P3—O2—K2^xv	94.82 (12)
O2^xviii—K1—O4^xvi	128.67 (9)	Fe1^xxii—O2—K2^xv	92.57 (10)
O4^xvii—K1—O4^xvi	82.84 (10)	P3—O2—K1^xiv	92.63 (12)
O4^xviii—K1—O4^xvi	82.84 (10)	Fe1^xxii—O2—K1^xiv	97.25 (10)
O1^xi—K1—P3^xviii	169.06 (5)	K2^xv—O2—K1^xiv	103.64 (9)
O1^xii—K1—P3^xviii	94.74 (5)	P3—O3—Fe2^vii	151.51 (19)
O1^x—K1—P3^xviii	79.13 (5)	P3—O3—K2^xiv	104.38 (14)
O2^xvi—K1—P3^xviii	108.35 (6)	Fe2^vii—O3—K2^xiv	100.00 (10)
O2^xvii—K1—P3^xviii	115.09 (6)	P3—O4—Fe2	152.6 (2)
O2^xviii—K1—P3^xviii	26.25 (5)	P3—O4—K2^xiv	98.53 (14)
O4^xvii—K1—P3^xviii	69.59 (5)	Fe2—O4—K2^xiv	95.14 (11)
O4^xviii—K1—P3^xviii	26.22 (5)	P3—O4—K1^xiv	88.41 (12)
O4^xvi—K1—P3^xviii	103.21 (8)	Fe2—O4—K1^xiv	117.90 (11)
O1^xi—K1—P3^xvii	79.13 (5)	K2^xiv—O4—K1^xiv	77.09 (8)
O1^xii—K1—P3^xvii	169.06 (5)	P3—O4—K2^xv	82.65 (13)
O1^x—K1—P3^xvii	94.74 (5)	Fe2—O4—K2^xv	87.54 (11)
O2^xvi—K1—P3^xvii	115.09 (6)	K2^xiv—O4—K2^xv	171.00 (11)
O2^xvii—K1—P3^xvii	26.25 (5)	K1^xiv—O4—K2^xv	94.06 (9)
O2^xviii—K1—P3^xvii	108.35 (6)

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

Funding information

This work was been supported by the Ministry of Education and Science of Ukraine: Grant of the Ministry of Education and Science of Ukraine for perspective development of the scientific direction `Mathematical sciences and natural sciences' at Taras Shevchenko National University of Kyiv.

References

Allen, F. H., Johnson, O., Shields, G. P., Smith, B. R. & Towler, M. (2004). J. Appl. Cryst. 37, 335–338. Web of Science CrossRef CAS IUCr Journals Google Scholar
Blessing, R. H. (1995). Acta Cryst. A51, 33–38. CrossRef CAS Web of Science IUCr Journals Google Scholar
Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854. Web of Science CrossRef CAS IUCr Journals Google Scholar
Gustafsson, J. C. M., Norberg, S. T., Svensson, G. & Albertsson, J. (2005). Acta Cryst. C61, i9–i13. Web of Science CrossRef ICSD IUCr Journals Google Scholar
Isasi, J. & Daidouh, A. (2000). Solid State Ionics, 133, 303–313. Web of Science CrossRef ICSD CAS Google Scholar
Luo, Y., Sun, T., Shui, M. & Shu, J. (2019). Mater. Chem. Phys. 233, 339–345. Web of Science CrossRef CAS Google Scholar
Mereiter, K. (1979). N. Jb. Mineral. Monatsh. pp. 182–188. Google Scholar
Norberg, S. T. (2002). Acta Cryst. B58, 743–749. Web of Science CrossRef ICSD CAS IUCr Journals Google Scholar
Nose, M., Nakayama, H., Nobuhara, K., Yamaguchi, H., Nakanishi, S. & Iba, H. (2013). J. Power Sources, 234, 175–179. Web of Science CrossRef CAS Google Scholar
Ogorodnyk, I. V., Baumer, V. N., Zatovsky, I. V., Slobodyanik, N. S., Shishkin, O. V. & Domasevitch, K. V. (2007a). Acta Cryst. B63, 819–827. Web of Science CrossRef IUCr Journals Google Scholar
Ogorodnyk, I. V., Zatovsky, I. V., Baumer, V. N., Slobodyanik, N. S., Shishkin, O. V. & Vorona, I. P. (2008). Z. Naturforsch. Teil B, 63, 261–266. CrossRef CAS Google Scholar
Ogorodnyk, I. V., Zatovsky, I. V. & Slobodyanik, N. S. (2007b). Russ. J. Inorg. Chem. 52, 121–125. Web of Science CrossRef Google Scholar
Ogorodnyk, I. V., Zatovsky, I. V., Slobodyanik, N. S., Baumer, V. N. & Shishkin, O. V. (2006). J. Solid State Chem. 179, 3461–3466. Web of Science CrossRef ICSD CAS Google Scholar
Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abingdon, England. Google Scholar
Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249–259. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Strutynska, N., Bondarenko, M., Slobodyanik, N., Baumer, V., Zatovsky, I., Bychkov, K. & Puzan, A. (2016). Cryst. Res. Technol. 51, 627–633. CrossRef CAS Google Scholar
Wang, D., Wei, Z., Lin, Y., Chen, N., Gao, Y., Chen, G., Song, L. & Du, F. (2019). J. Mater. Chem. A, 7, 20604–20613. CrossRef CAS Google Scholar
Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925. Web of Science CrossRef CAS IUCr Journals Google Scholar
Zatovskii, I. V., Slobodyanik, N. S., Ushchapivskaya, T. I., Ogorodnik, I. V. & Babarik, A. A. (2006). Russ. J. Appl. Chem. 79, 10–15. CrossRef CAS Google Scholar
Zatovsky, I. V., Strutynska, N. Yu., Hizhnyi, Y. A., Nedilko, S. G., Slobodyanik, N. S. & Klyui, N. I. (2018). ChemistryOpen, 7, 504–512. CrossRef CAS PubMed Google Scholar
Zatovsky, I. V., Strutynska, N. Yu., Ogorodnyk, I. V., Baumer, V. N., Slobodyanik, N. S., Yatskin, M. M. & Odynets, I. V. (2016). Struct. Chem. 27, 323–330. CrossRef ICSD CAS Google Scholar
Zemann, A. & Zemann, J. (1957). Acta Cryst. 10, 409–413. CrossRef ICSD CAS IUCr Journals Web of Science Google Scholar
Zhang, B., Ma, K., Lv, X., Shi, K., Wang, Y., Nian, Z., Li, Y., Wang, L., Dai, L. & He, Z. (2021). J. Alloys Compd. 867, 159060. CrossRef Google Scholar

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Volume 77| Part 12| December 2021| Pages 1299-1302

https://doi.org/10.1107/S2056989021011877

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