K₆[Fe_8.27(HPO₃)₁₂]: a new mixed-valence iron phosphite

The title compound, hexa­potassium octa­iron(II,III) dodeca­phosphon­ate, exhibiting a two-dimensional structure, is a new mixed alkali/3d metal phosphite. It crystallizes in the space group Rm, with two crystallographically independent Fe atoms occupying sites of m (Fe1) and 3m (Fe2) symmetry. The Fe2 site is fully occupied, whereas the Fe1 site presents an occupancy factor of 0.757 (3). The three independent O atoms, one of which is disordered, are situated on a mirror and all other atoms are located on special positions with 3m symmetry. Layers of formula [Fe₃(HPO₃)₄]²⁻ are observed in the structure, formed by linear Fe₃O₁₂ trimer units, which contain face-sharing FeO₆ octa­hedra inter­connected by (HPO₃)²⁻ phosphite oxoanions. The partial occupancy of the Fe1 site might be described by the formation of two [Fe(HPO₃)₂]⁻ layers derived from the [Fe₃(HPO₃)₄]²⁻ layer when the Fe1 atom is absent. Fe²⁺ is localized at the Fe1 and Fe2 sites of the [Fe₃(HPO₃)₄]²⁻ sheets, whereas Fe³⁺ is found at the Fe2 sites of the [Fe(HPO₃)₂]⁻ sheets, according to bond-valence calculations. The K⁺ cations are located in the inter­layer spaces, between the [Fe₃(HPO₃)₄]²⁻ layers, and between the [Fe₃(HPO₃)₄]²⁻ and [Fe(HPO₃)₂]⁻ layers.

S1. Introduction

Over the last few decades, the synthesis of transition metal phosphates with open-framework structures has been an area of intense research due to their potential applications in catalysis, adsorption, ionic conduction, ion exchange, magnetism and electronics (Cheetham et al., 1999). More recently, it became apparent that the phosphite group, (HPO₃)^2-, which is closely related to the tetra­hedral phosphate group, (PO₄)^3-, can also be incorporated as a basic building unit of the framework structure. In this hydrogen phosphite group, the P atom remains in a low oxidation state of +3 and the group has trigonal pyramidal geometry. A careful study of the literature clearly shows that since the first organically templated vanadium phosphite with an open framework was isolated (Bonavia et al., 1995), the family of transition metal phosphites has grown rapidly and numerous compounds with inter­esting diversity have been reported (Natarajan & Mandal, 2008; Rojo et al., 2009). However, compared with the related phosphates, iron phosphites have not been studied widely and only a few iron phosphites with two- (Chung et al., 2004; Hamchaoui, Alonzo et al., 2013 or Hamchaoui, Rebbah & Le Fur, 2013 ?) and three-dimensional (Sghyar et al., 1991; Poojary et al., 1994; Attfield et al., 1994; Fan et al., 2005; Liu et al., 2005; Chung et al., 2006; Mandal et al., 2008; Chung et al., 2011) structures have been synthesized and characterized. Among them, only a few contain iron in both valence states. In order to enlarge the phosphite materials family incorporating metallic magnetic cations belonging to the first series of transition elements, particularly in the presence of a second metal atom, our work has focused on the alkali metal–iron–phosphite acid system. During our investigations, we obtained the title compound, K₆[Fe_8.27(HPO₃)₁₂], using hydro­thermal treatment and autogenous pressure.

S2. Experimental

S2.1. Synthesis and crystallization

K₆[Fe_8.27(HPO₃)₁₂] was synthesized by a hydro­thermal method. A mixture of FeSO₄.7H₂O (Merck, 99.5%), H₃PO₃ (Aldrich, 99%), K₂CO₃ (Merck, 99%) and deionized water in a 0.2:1.5:0.8:28 molar ratio was placed in a Teflon acid digestion bomb (23 ml, Parr Instruments), heated at 453 K for 72 h and cooled slowly to room temperature. The product obtained was filtered off, washed with deionized water and dried in a desiccator. Medium dark-grey crystals were selected for the structural study. Comparison of the X-ray powder diffraction pattern of the synthesized product with that simulated from the structure of K₆[Fe_8.27(HPO₃)₁₂] revealed that the title compound as obtained is not pure.

S2.2. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. Both H atoms were located from a Fourier difference map and their U_iso(H) values were constrained to be 1.2U_eq of the attached P atom.

S3. Comment

The crystal structure of K₆[Fe_8.27(HPO₃)₁₂] consists of a two-dimensional framework built up from iron cations adopting an o­cta­hedral environment and P^III cations exhibiting pseudo­tetra­hedral geometry. As shown in Fig. 1, there are two crystallographically independent Fe atoms in the asymmetric unit of the title compound. They occupy two different special sites; the Fe2 site is fully occupied, whereas the Fe1 site presents an occupational disorder with an occupancy of 0.757. The O atoms are located on three special positions (18h); the O1 site is fully occupied, and atoms O2A and O2B present positional disorder with occupancies of 0.757 and 0.243, respectively. Six O atoms define an o­cta­hedral geometry around the metallic centre, while three O atoms and one H atom define the pseudo­tetra­hedral environment of the P atom. The connection of the Fe1(O2A)₆ and Fe2(O1)₃(O2A)₃ o­cta­hedra by face-sharing forms a linear Fe₃O₁₂ trimer unit, where atom Fe1 is located at the centre and atom Fe2 at the extremes. The phosphite groups link these trimeric entities through the O atoms (Fig. 2a), leading to [Fe₃(HPO₃)₄]^2- layers which propagate in the ab plane (Fig. 2b). This kind of layering has been encountered in some transition metal phosphites (Fernandez et al., 2000, 2001; Chung et al., 2004; Hamchaoui et al., 2009; Duan et al., 2013).

To continue the structural description of the title compound, we can assume that the absence of the Fe1 atom, due to the partial occupancy of its site, leads to the formation of two [Fe(HPO₃)₂]^- layers (Fig. 2c) instead of the [Fe₃(HPO₃)₄]^2- triple layer. Such monolayers have also previously been observed in some phosphite compounds (Li et al., 2013; Wang et al., 2013; Hamchaoui, Alonzo et al., 2013; Hamchaoui, Rebbah & Le Fur, 2013). Each isolated Fe2O₆ o­cta­hedron then shares its six apices with hydrogen phosphite groups. Reciprocally, each HPO₃ trigonal pyramid shares all its O atoms with three different metallic centres. Finally, the association of FeO₆ and HPO₃ polyhedra leads to a layered structure formed by sheets of [Fe₃(HPO₃)₄]^2- and [Fe(HPO₃)₂]^- formula units stacked in a disordered way along the c axis (Fig. 3). While these anionic sheets are known separately, the title compound is the first example with the simultaneous presence of both.

The K⁺ cations are located between the [Fe₃(HPO₃)₄]^2- layers, and between the [Fe₃(HPO₃)₄]^2- and [Fe(HPO₃)₂]^- layers, compensating their negative charge. They are in ninefold coordination sites, with inter­actions to six nearest-neighbour O atoms from one layer and three further ones from an adjacent layer (Fig. 4). The coordination environment adopted by the alkali cation is supported by bond-valence sum (BVS) calculations (Brown & Altermatt, 1985) which give a value of 1.27 valence units (v.u.) for K.

The formation of the mixed-valence iron phosphite indicates the partial oxidation of this metal during the reaction. The BVS calculations give an oxidation state of 1.94 for atom Fe1. As mentioned above, a statistical disorder is observed on two O atoms (O2A and O2B) surrounding atom Fe2. These two atoms cannot be present at the same time, due to very short O2A—O2B distance (calculated distance of ca 0.5 Å). Consequently, two distinct o­cta­hedral environments can be defined for Fe2: Fe2(O1)₃(O2A)₃ and Fe2(O1)₃(O2B)₃, for which the BVS values are 2.04 and 2.88 v.u., respectively. A mean value of 2.25 can be estimated for Fe2, considering the occupancy factors of atoms O2A and O2B. As described previously, when atom O2A is present the trimeric [Fe₃(HPO₃)₄]^2- layer is observed with divalent iron (Fe^II) and when O2B is present [Fe(HPO₃)₂]^- monolayers with trivalent iron (Fe^III) are observed, in agreement with the literature. The disordered situation in the title structure is extended to one phosphite group, in which atom P2 is surrounded statistically by atoms O2A and O2B, while no disorder is observed around atom P1.

It is inter­esting to mention that transition metal phosphites showing the same [M₃(HPO₃)₄]^2- sheets as exhibited by the title compound, viz. the two purely inorganic phosphite compounds, K₂[Mn₃(HPO₃)₄] and (H₃O)₂[Co₃(HPO₃)]₄ (Duan et al., 2013), are isotypic with K₆[Fe_8.27(HPO₃)₁₂], neglecting disorder in the cobalt and iron phosphites. In the other A[M₃(HPO₃)₄] compounds [A = C₂H₁₀N₂ (name?) and M = Mn (Fernandez et al., 2000); A = C₃H₁₂N₂ (name?) and M = Mn (Fernandez et al., 2001); A = C₂H₁₀N₂ (name?) and M = Co (Fernandez et al., 2001); A = C₂H₁₀N₂ (name?) and M = Fe (Chung et al., 2004)], the absence of the threefold axis, due to the geometry of the inter­calated cations in the inter­layer space, leads to lower symmetries compared with the trigonal symmetry obtained with the presence of K⁺ or H₃O⁺ cations in the structure. The A[M(HPO₃)₂] phosphite compounds [A = H₃O⁺ and M = In (Li et al., 2013); A = Rb and M = In (Wang et al., 2013); A = K, NH₄ and Rb, and M = V and Fe (Hamchaoui, Alonzo et al., 2013; OR Hamchaoui, Rebbah & Le Fur, 2013); A = NH₄ and M = In (Hamchaoui, Alonzo et al., 2013; OR Hamchaoui, Rebbah & Le Fur, 2013)] showing the same [M(HPO₃)₂]^- sheets as exhibited by the title compound are all isotypic and their structures are described in the hexagonal P6₃mc space group. Finally, the potassium-ion environment described here compares favourably with those observed for K[M(HPO₃)₂] (M = V and Fe) and K₂[Mn₃(HPO₃)₄].

Related literature

For related literature, see: Attfield et al. (1994); Bonavia et al. (1995); Brown & Altermatt (1985); Cheetham et al. (1999); Chung et al. (2004, 2006, 2011); Duan et al. (2013); Fan et al. (2005); Fernandez et al. (2000, 2001); Hamchaoui et al. (2009); Hamchaoui, Alonzo, Venegas-Yazigi, Rebbah & Le Fur (2013); Hamchaoui, Rebbah & Le Fur (2013); Li et al. (2013); Liu et al. (2005); Mandal et al. (2008); Natarajan & Mandal (2008); Poojary et al. (1994); Rojo et al. (2009); Sghyar et al. (1991); Wang et al. (2013).

Computing details

Data collection: COLLECT (Nonius, 1998); cell refinement: DIRAX/LSQ (Duisenberg et al., 2000); data reduction: EVALCCD (Duisenberg et al., 2003); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXL97 (Sheldrick, 2008); software used to prepare material for publication: WinGX (Farrugia, 2012).

Figures

	Fig. 1. The asymmetric unit and symmetry-related atoms of K6[Fe8.27(HPO3)12], showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (ii) -x, -y, -z; (iii) y, -x + y, -z; (iv) -x + y, -x, z; (v) -y, x - y, z; (vi) -x + y, -x + 1, z; (vii) -y + 1, x - y, z; (viii) -x + y + 1, -x + 1, z; (ix) x - y, x, -z; (x) -y + 1, x - y + 1, z.]
	Fig. 2. Projections along (a) the [010] direction, showing the [Fe3(HPO3)4] layer in K6[Fe8.27(HPO3)12], (b) the [001] direction, showing the [Fe3(HPO3)4] layer in K6[Fe8.27(HPO3)12], and (c) the [010] direction, showing the [Fe(HPO3)2] layers in K6[Fe8.27(HPO3)12].
	Fig. 3. A projection along the [010] direction, showing the two-dimensional framework in K6[Fe8.27(HPO3)12].
	Fig. 4. The ninefold coordination of the K^+ cation in K6[Fe8.27(HPO3)12]. [Symmetry codes: (i) y + 2/3, -x + y + 1/3, -z + 1/3; (iv) -x + y, -x, z; (vii) -y + 1, x - y, z; (viii) -x + y + 1, -x + 1, z; (x) -y + 1, x - y + 1, z; (xi) x + 1, y, z; (xii) -x + 2/3, -y + 1/3, -z + 1/3; (xiii) x - y + 2/3, x + 1/3, -z + 1/3.]

Hexapotassium octairon(II,III) dodecaphosphonate

Crystal data

K6[Fe8.27(HPO3)12]	Dx = 3.164 Mg m^−3
Mr = 1656.18	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3m	Cell parameters from 1362 reflections
Hall symbol: -R 3 2"	θ = 2.9–42.1°
a = 5.3822 (1) Å	µ = 4.75 mm^−1
c = 34.6521 (8) Å	T = 293 K
V = 869.32 (3) Å^3	Prism, dark grey
Z = 1	0.08 × 0.05 × 0.05 mm
F(000) = 809

Data collection

Nonius KappaCCD area-detector diffractometer	633 reflections with I > 2σ(I)
CCD rotation images, thick slices scans	Rint = 0.032
Absorption correction: multi-scan (SADABS; Sheldrick, 2002)	θmax = 40.0°, θmin = 3.5°
Tmin = 0.684, Tmax = 0.789	h = −9→9
6203 measured reflections	k = −9→9
748 independent reflections	l = −62→58

Refinement

Refinement on F^2	Only H-atom coordinates refined
Least-squares matrix: full	w = 1/[σ^2(Fo^2) + (0.0469P)^2 + 0.4877P] where P = (Fo^2 + 2Fc^2)/3
R[F^2 > 2σ(F^2)] = 0.027	(Δ/σ)max < 0.001
wR(F^2) = 0.070	Δρmax = 1.69 e Å^−3
S = 1.01	Δρmin = −1.07 e Å^−3
748 reflections	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
33 parameters	Extinction coefficient: 0.0017 (5)
2 restraints

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Fe1	0	0	0	0.01012 (18)	0.757 (3)
Fe2	0	0	0.083444 (11)	0.00926 (10)
P1	0.3333	0.6667	0.10603 (2)	0.00972 (13)
H1	0.3333	0.6667	0.0658 (5)	0.012*
P2	0.6667	0.3333	0.03222 (2)	0.01131 (14)
H2	0.6667	0.3333	−0.0081 (5)	0.014*
O1	0.17710 (13)	0.3542 (3)	0.11944 (3)	0.0143 (2)
O2A	0.3501 (4)	0.17506 (18)	0.04047 (5)	0.0133 (3)	0.757 (3)
O2B	0.3719 (12)	0.1860 (6)	0.05498 (18)	0.0133 (3)	0.243 (3)
K1	0.6667	0.3333	0.14646 (2)	0.01822 (14)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Fe1	0.0096 (2)	0.0096 (2)	0.0112 (3)	0.00480 (11)	0	0
Fe2	0.00826 (12)	0.00826 (12)	0.01126 (17)	0.00413 (6)	0	0
P1	0.00850 (18)	0.00850 (18)	0.0122 (2)	0.00425 (9)	0	0
P2	0.00945 (18)	0.00945 (18)	0.0150 (3)	0.00473 (9)	0	0
O1	0.0148 (4)	0.0095 (5)	0.0169 (4)	0.0048 (2)	0.00020 (19)	0.0004 (4)
O2A	0.0073 (5)	0.0139 (4)	0.0164 (8)	0.0036 (3)	−0.0017 (6)	−0.0009 (3)
O2B	0.0073 (5)	0.0139 (4)	0.0164 (8)	0.0036 (3)	−0.0017 (6)	−0.0009 (3)
K1	0.01617 (18)	0.01617 (18)	0.0223 (3)	0.00808 (9)	0	0

Geometric parameters (Å, º)

Fe1—O2A^i	2.1517 (18)	P1—K1	3.4087 (4)
Fe1—O2A	2.1517 (18)	P1—H1	1.392 (19)
Fe1—O2A^ii	2.1517 (18)	P2—O2A^xi	1.5029 (16)
Fe1—O2A^iii	2.1517 (18)	P2—O2A	1.5029 (16)
Fe1—O2A^iv	2.1517 (18)	P2—O2A^xii	1.5029 (16)
Fe1—O2A^v	2.1517 (18)	P2—O2B^xi	1.584 (6)
Fe1—Fe2	2.8915 (4)	P2—O2B^xii	1.584 (6)
Fe1—Fe2^i	2.8915 (4)	P2—O2B	1.584 (6)
Fe2—O2B^v	1.995 (6)	P2—H2	1.396 (18)
Fe2—O2B^iv	1.995 (6)	O1—K1^vii	2.8510 (4)
Fe2—O2B	1.995 (6)	O1—K1	2.8510 (4)
Fe2—O1	2.0692 (12)	O1—K1^vi	2.8612 (13)
Fe2—O1^iv	2.0692 (12)	O2A—O2B	0.513 (5)
Fe2—O1^v	2.0692 (12)	K1—O1^v	2.8510 (4)
Fe2—O2A^v	2.2093 (17)	K1—O1^xiii	2.8510 (4)
Fe2—O2A^iv	2.2093 (17)	K1—O1^xi	2.8510 (4)
Fe2—O2A	2.2093 (17)	K1—O1^ix	2.8510 (4)
Fe2—K1^vi	3.5842 (8)	K1—O1^xii	2.8510 (4)
Fe2—K1^vii	3.7979 (4)	K1—O1^xiv	2.8612 (13)
P1—O1^viii	1.5288 (12)	K1—O1^vi	2.8612 (13)
P1—O1^ix	1.5288 (12)	K1—O1^xv	2.8612 (13)
P1—O1	1.5288 (12)	K1—K1^xvi	3.4084 (6)
P1—K1^x	3.4087 (4)	K1—K1^xvii	3.4085 (6)
P1—K1^vii	3.4087 (4)	K1—K1^vi	3.4085 (6)
O2A^i—Fe1—O2A	180.00 (9)	O1—P1—H1	107.70 (5)
O2A^i—Fe1—O2A^ii	82.12 (7)	K1^x—P1—H1	114.269 (15)
O2A—Fe1—O2A^ii	97.88 (7)	K1^vii—P1—H1	114.269 (15)
O2A^i—Fe1—O2A^iii	82.12 (7)	K1—P1—H1	114.269 (15)
O2A—Fe1—O2A^iii	97.88 (7)	O2A^xi—P2—O2A	116.47 (5)
O2A^ii—Fe1—O2A^iii	82.12 (7)	O2A^xi—P2—O2A^xii	116.47 (5)
O2A^i—Fe1—O2A^iv	97.88 (7)	O2A—P2—O2A^xii	116.47 (5)
O2A—Fe1—O2A^iv	82.12 (7)	O2A^xi—P2—O2B^xi	18.89 (19)
O2A^ii—Fe1—O2A^iv	180.00 (8)	O2A—P2—O2B^xi	109.34 (13)
O2A^iii—Fe1—O2A^iv	97.88 (7)	O2A^xii—P2—O2B^xi	109.34 (13)
O2A^i—Fe1—O2A^v	97.88 (7)	O2A^xi—P2—O2B^xii	109.34 (13)
O2A—Fe1—O2A^v	82.12 (7)	O2A—P2—O2B^xii	109.34 (13)
O2A^ii—Fe1—O2A^v	97.88 (7)	O2A^xii—P2—O2B^xii	18.89 (19)
O2A^iii—Fe1—O2A^v	180.00 (9)	O2B^xi—P2—O2B^xii	97.4 (3)
O2A^iv—Fe1—O2A^v	82.12 (7)	O2A^xi—P2—O2B	109.34 (13)
O2A^i—Fe1—Fe2	130.67 (5)	O2A—P2—O2B	18.89 (19)
O2A—Fe1—Fe2	49.33 (5)	O2A^xii—P2—O2B	109.34 (13)
O2A^ii—Fe1—Fe2	130.67 (5)	O2B^xi—P2—O2B	97.4 (3)
O2A^iii—Fe1—Fe2	130.67 (5)	O2B^xii—P2—O2B	97.4 (3)
O2A^iv—Fe1—Fe2	49.33 (5)	O2A^xi—P2—H2	100.96 (8)
O2A^v—Fe1—Fe2	49.33 (5)	O2A—P2—H2	100.96 (8)
O2A^i—Fe1—Fe2^i	49.33 (5)	O2A^xii—P2—H2	100.96 (8)
O2A—Fe1—Fe2^i	130.67 (5)	O2B^xi—P2—H2	119.9 (2)
O2A^ii—Fe1—Fe2^i	49.33 (5)	O2B^xii—P2—H2	119.9 (2)
O2A^iii—Fe1—Fe2^i	49.33 (5)	O2B—P2—H2	119.9 (2)
O2A^iv—Fe1—Fe2^i	130.67 (5)	P1—O1—Fe2	125.23 (7)
O2A^v—Fe1—Fe2^i	130.67 (5)	P1—O1—K1^vii	97.61 (3)
Fe2—Fe1—Fe2^i	180	Fe2—O1—K1^vii	99.83 (3)
O2B^v—Fe2—O2B^iv	97.6 (2)	P1—O1—K1	97.61 (3)
O2B^v—Fe2—O2B	97.6 (2)	Fe2—O1—K1	99.83 (3)
O2B^iv—Fe2—O2B	97.6 (2)	K1^vii—O1—K1	141.44 (5)
O2B^v—Fe2—O1	172.57 (18)	P1—O1—K1^vi	142.94 (7)
O2B^iv—Fe2—O1	87.21 (13)	Fe2—O1—K1^vi	91.83 (4)
O2B—Fe2—O1	87.21 (13)	K1^vii—O1—K1^vi	73.27 (2)
O2B^v—Fe2—O1^iv	87.21 (13)	K1—O1—K1^vi	73.27 (2)
O2B^iv—Fe2—O1^iv	87.21 (13)	O2B—O2A—P2	89.5 (7)
O2B—Fe2—O1^iv	172.57 (18)	O2B—O2A—Fe1	142.1 (7)
O1—Fe2—O1^iv	87.42 (5)	P2—O2A—Fe1	128.37 (11)
O2B^v—Fe2—O1^v	87.21 (13)	O2B—O2A—Fe2	59.0 (7)
O2B^iv—Fe2—O1^v	172.57 (18)	P2—O2A—Fe2	148.58 (12)
O2B—Fe2—O1^v	87.21 (13)	Fe1—O2A—Fe2	83.05 (6)
O1—Fe2—O1^v	87.42 (5)	O2A—O2B—P2	71.6 (7)
O1^iv—Fe2—O1^v	87.42 (5)	O2A—O2B—Fe2	108.2 (8)
O2B^v—Fe2—O2A^v	12.74 (16)	P2—O2B—Fe2	179.8 (4)
O2B^iv—Fe2—O2A^v	89.29 (15)	O1^v—K1—O1^xiii	109.77 (2)
O2B—Fe2—O2A^v	89.29 (15)	O1^v—K1—O1^xi	52.51 (5)
O1—Fe2—O2A^v	174.69 (6)	O1^xiii—K1—O1^xi	60.20 (5)
O1^iv—Fe2—O2A^v	96.41 (4)	O1^v—K1—O1^ix	109.77 (2)
O1^v—Fe2—O2A^v	96.41 (4)	O1^xiii—K1—O1^ix	109.77 (2)
O2B^v—Fe2—O2A^iv	89.29 (15)	O1^xi—K1—O1^ix	141.44 (5)
O2B^iv—Fe2—O2A^iv	12.74 (16)	O1^v—K1—O1^xii	141.44 (5)
O2B—Fe2—O2A^iv	89.29 (15)	O1^xiii—K1—O1^xii	52.51 (5)
O1—Fe2—O2A^iv	96.41 (4)	O1^xi—K1—O1^xii	109.77 (2)
O1^iv—Fe2—O2A^iv	96.41 (4)	O1^ix—K1—O1^xii	60.20 (5)
O1^v—Fe2—O2A^iv	174.69 (6)	O1^v—K1—O1	60.20 (5)
O2A^v—Fe2—O2A^iv	79.54 (7)	O1^xiii—K1—O1	141.44 (5)
O2B^v—Fe2—O2A	89.29 (15)	O1^xi—K1—O1	109.77 (2)
O2B^iv—Fe2—O2A	89.29 (15)	O1^ix—K1—O1	52.51 (5)
O2B—Fe2—O2A	12.74 (16)	O1^xii—K1—O1	109.77 (2)
O1—Fe2—O2A	96.41 (4)	O1^v—K1—O1^xiv	136.892 (19)
O1^iv—Fe2—O2A	174.69 (6)	O1^xiii—K1—O1^xiv	77.68 (4)
O1^v—Fe2—O2A	96.41 (4)	O1^xi—K1—O1^xiv	106.73 (2)
O2A^v—Fe2—O2A	79.54 (7)	O1^ix—K1—O1^xiv	106.73 (2)
O2A^iv—Fe2—O2A	79.54 (7)	O1^xii—K1—O1^xiv	77.68 (4)
O2B^v—Fe2—Fe1	60.36 (17)	O1—K1—O1^xiv	136.892 (19)
O2B^iv—Fe2—Fe1	60.36 (17)	O1^v—K1—O1^vi	77.68 (4)
O2B—Fe2—Fe1	60.36 (17)	O1^xiii—K1—O1^vi	106.73 (2)
O1—Fe2—Fe1	127.07 (3)	O1^xi—K1—O1^vi	77.68 (4)
O1^iv—Fe2—Fe1	127.07 (3)	O1^ix—K1—O1^vi	136.892 (19)
O1^v—Fe2—Fe1	127.07 (3)	O1^xii—K1—O1^vi	136.892 (19)
O2A^v—Fe2—Fe1	47.62 (5)	O1—K1—O1^vi	106.73 (2)
O2A^iv—Fe2—Fe1	47.62 (5)	O1^xiv—K1—O1^vi	59.96 (4)
O2A—Fe2—Fe1	47.62 (5)	O1^v—K1—O1^xv	106.73 (2)
O2B^v—Fe2—K1^vi	119.64 (17)	O1^xiii—K1—O1^xv	136.892 (19)
O2B^iv—Fe2—K1^vi	119.64 (17)	O1^xi—K1—O1^xv	136.892 (19)
O2B—Fe2—K1^vi	119.64 (17)	O1^ix—K1—O1^xv	77.68 (4)
O1—Fe2—K1^vi	52.93 (3)	O1^xii—K1—O1^xv	106.73 (2)
O1^iv—Fe2—K1^vi	52.93 (3)	O1—K1—O1^xv	77.68 (4)
O1^v—Fe2—K1^vi	52.93 (3)	O1^xiv—K1—O1^xv	59.96 (4)
O2A^v—Fe2—K1^vi	132.38 (5)	O1^vi—K1—O1^xv	59.96 (4)
O2A^iv—Fe2—K1^vi	132.38 (5)	O1^v—K1—K1^xvi	95.96 (2)
O2A—Fe2—K1^vi	132.38 (5)	O1^xiii—K1—K1^xvi	53.50 (2)
Fe1—Fe2—K1^vi	180	O1^xi—K1—K1^xvi	53.50 (2)
O2B^v—Fe2—K1^vii	129.79 (7)	O1^ix—K1—K1^xvi	153.61 (2)
O2B^iv—Fe2—K1^vii	64.74 (17)	O1^xii—K1—K1^xvi	95.96 (2)
O2B—Fe2—K1^vii	129.79 (7)	O1—K1—K1^xvi	153.61 (2)
O1—Fe2—K1^vii	47.701 (10)	O1^xiv—K1—K1^xvi	53.229 (15)
O1^iv—Fe2—K1^vii	47.701 (10)	O1^vi—K1—K1^xvi	53.229 (15)
O1^v—Fe2—K1^vii	107.83 (4)	O1^xv—K1—K1^xvi	100.98 (4)
O2A^v—Fe2—K1^vii	133.609 (10)	O1^v—K1—K1^xvii	153.61 (2)
O2A^iv—Fe2—K1^vii	77.48 (5)	O1^xiii—K1—K1^xvii	95.96 (2)
O2A—Fe2—K1^vii	133.609 (10)	O1^xi—K1—K1^xvii	153.61 (2)
Fe1—Fe2—K1^vii	125.096 (9)	O1^ix—K1—K1^xvii	53.50 (2)
K1^vi—Fe2—K1^vii	54.903 (9)	O1^xii—K1—K1^xvii	53.50 (2)
O1^viii—P1—O1^ix	111.18 (5)	O1—K1—K1^xvii	95.96 (2)
O1^viii—P1—O1	111.18 (5)	O1^xiv—K1—K1^xvii	53.228 (15)
O1^ix—P1—O1	111.18 (5)	O1^vi—K1—K1^xvii	100.98 (4)
O1^viii—P1—K1^x	56.000 (16)	O1^xv—K1—K1^xvii	53.228 (15)
O1^ix—P1—K1^x	56.000 (16)	K1^xvi—K1—K1^xvii	104.28 (2)
O1—P1—K1^x	138.03 (6)	O1^v—K1—K1^vi	53.50 (2)
O1^viii—P1—K1^vii	56.000 (16)	O1^xiii—K1—K1^vi	153.61 (2)
O1^ix—P1—K1^vii	138.03 (6)	O1^xi—K1—K1^vi	95.96 (2)
O1—P1—K1^vii	56.000 (16)	O1^ix—K1—K1^vi	95.96 (2)
K1^x—P1—K1^vii	104.275 (17)	O1^xii—K1—K1^vi	153.61 (2)
O1^viii—P1—K1	138.03 (6)	O1—K1—K1^vi	53.50 (2)
O1^ix—P1—K1	56.000 (16)	O1^xiv—K1—K1^vi	100.98 (4)
O1—P1—K1	56.000 (16)	O1^vi—K1—K1^vi	53.228 (15)
K1^x—P1—K1	104.275 (17)	O1^xv—K1—K1^vi	53.228 (15)
K1^vii—P1—K1	104.275 (17)	K1^xvi—K1—K1^vi	104.29 (2)
O1^viii—P1—H1	107.70 (5)	K1^xvii—K1—K1^vi	104.28 (2)
O1^ix—P1—H1	107.70 (5)

Symmetry codes: (i) −x, −y, −z; (ii) y, −x+y, −z; (iii) x−y, x, −z; (iv) −y, x−y, z; (v) −x+y, −x, z; (vi) −x+2/3, −y+1/3, −z+1/3; (vii) x−1, y, z; (viii) −x+y, −x+1, z; (ix) −y+1, x−y+1, z; (x) x, y+1, z; (xi) −y+1, x−y, z; (xii) −x+y+1, −x+1, z; (xiii) x+1, y, z; (xiv) y+2/3, −x+y+1/3, −z+1/3; (xv) x−y+2/3, x+1/3, −z+1/3; (xvi) −x+5/3, −y+1/3, −z+1/3; (xvii) −x+5/3, −y+4/3, −z+1/3.