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Synthesis and crystal structure of a new magnesium phosphate Na3RbMg7(PO4)6

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aUnité de recherche, Matériaux Inorganiques, Faculté des Sciences, Université de Monastir, 5019, Monastir, Tunisia
*Correspondence e-mail: teycirbenhamed@yahoo.fr

Edited by I. D. Brown, McMaster University, Canada (Received 15 March 2017; accepted 27 April 2017; online 5 May 2017)

A new magnesium phosphate, Na3RbMg7(PO4)6 [tris­odium rubidium hepta­magnesium hexakis(ortho­phosphate)], has been synthesized as single crystals by the flux method and exhibits a new structure type. Its original structure is built up from MgOx (x = 5 and 6) polyhedra linked directly to each other through common corners or edges and reinforced by corner-sharing with PO4 tetra­hedra. The resulting anionic three-dimensional framework leads to the formation of channels along the [010] direction, in which the Na+ cations are located, while the Rb+ cations are located in large inter­stitial cavities.

1. Chemical context

Magnesium phosphates are of increasing inter­est because of their potential applications as host materials for optically active rare earth ions (Seo, 2013[Seo, H. J. (2013). J. Ceram. Process. Res. 14(1), 22-25.]; Kim et al., 2013[Kim, S. W., Hasegawa, T., Ishigaki, T. K., Uematsu, K., Toda, K. & Sato, M. (2013). ECS Solid State Letters, 2, R49-R51.]; Boukhris et al., 2015[Boukhris, A., Glorieux, B. & Ben Amara, M. (2015). J. Mol. Struct. 1083, 319-329.]). Moreover, these materials are very attractive in terms of basic research because they exhibit a rich structural chemistry due to their polymorphism (Ait Benhamou et al., 2010[Ait Benhamou, R., Wallez, G., Loiseau, P., Viana, B., Elaatmani, M., Daoud, M. & Zegzouti, A. (2010). J. Solid State Chem. 183, 2082-2086.]; Orlova et al., 2015[Orlova, M., Khainakov, S., Michailov, D., Perfler, L., Langes, Ch., Kahlenberg, V. & Orlova, A. (2015). J. Solid State Chem. 221, 224-229.]).

Among the variety of magnesium monophosphates synthesized and characterized up to now, only four compounds belong to the system Na3PO4–Mg3(PO4)2, namely NaMgPO4, NaMg4(PO4)3, Na2Mg5(PO4)4 and Na4Mg(PO4)2 (Imura & Kawahara, 1997[Imura, H. & Kawahara, A. (1997). Acta Cryst. C53, 1733-1735.]; Ben Amara et al., 1983[Ben Amara, M., Vlasse, M., Olazcuaga, R., Le Flem, G. & Hagenmuller, P. (1983). Acta Cryst. C39, 936-939.]; Yamakawa et al., 1994[Yamakawa, J., Yamada, T. & Kawahara, A. (1994). Acta Cryst. C50, 986-988.]; Ghorbel et al., 1974[Ghorbel, A., d'Yvoire, F. & Dorrmieux-Morin, C. (1974). Bull. Soc. Chim. Fr. pp. 1239-1242.]). NaMgPO4 compound crystallizes in the ortho­rhom­bic system with space group P212121. Its structure involves MgO6 and MgO5 polyhedra linked by the monophosphate groups that form a three-dimensional framework. NaMg4(PO4)3 is also ortho­rhom­bic, space group Pnma. Its structure is built up from three kinds of MgO5 units sharing edges and corners and linked to each other by the PO4 tetra­hedra, leading to a three-dimensional framework. Na2Mg5(PO4)4, synthesized under pressure, crystallizes in the triclinic system. Its structure results from a three-dimensional framework of MgO6 and MgO5 polyhedra connected either directly via common corners or by means of the phosphate groups. Na4Mg(PO4)2 exhibits two polymorphs, which were only identified by their powder diffraction patterns.

Starting from these compounds, suitable replacements of magnesium and/or sodium by large cations induces their transformation into several structural types for different Mg/P atomic ratios. NaMMg(PO4)2 (M = Ca, Sr and Ba) compounds are related to the glaserite-type structure (Alkemper & Fuess, 1998[Alkemper, J. & Fuess, H. (1998). Z. Kristallogr. 213, 282-287.]; Boukhris et al., 2012[Boukhris, A., Hidouri, M., Glorieux, B. & Ben Amara, M. (2012). Mater. Chem. Phys. 137, 26-33.], 2013[Boukhris, A., Hidouri, M., Glorieux, B. & Ben Amara, M. (2013). J. Rare Earths, 31, 849-856.]). They adopt an anionic two-dimensional network with different symmetries as a function of the size of the M2+ cation. For an atomic ratio M:P of 7:6, magnesium phosphate compounds adopt a three-dimensional network related to the fillowite-type structure, as observed in Na4Ca4Mg21(PO4)18, Na2CaMg7(PO4)6 and Na2.5Y0.5Mg7(PO4)6 (Domanskii et al., 1982[Domanskii, A. I., Smolin, Yu. I., Shepelev, Yu. F. & Majling, J. (1982). Sov. Phys. Crystallogr. 27, 535-537.]; McCoy et al., 1994[McCoy, T. J., Steele, I. M., Keil, K., Leonard, B. F. & Endress, M. (1994). Am. Mineral. 79, 375-380.]; Jerbi et al., 2010a[Jerbi, H., Hidouri, M. & Ben Amara, M. (2010a). J. Rare Earths, 28, 481-487.]). All of them crystallize with trigonal symmetry (space group R[\overline{3}]) and differ only by their cationic distributions. Three-dimensional anionic networks includes also original structures such as those observed in Na18Ca13Mg5(PO4)18, NaCa9Mg(PO4)7, Na7LnMg13(PO4)12 (Ln = La, Eu, Nd) (Yamakawa et al., 1994[Yamakawa, J., Yamada, T. & Kawahara, A. (1994). Acta Cryst. C50, 986-988.]; Morozov et al., 1997[Morozov, V. A., Presnyakov, I. A., Belik, A. A., Khasanov, S. S. & Lazoryak, B. I. (1997). Kristallografiya, 42, 825-836.]; Jerbi et al., 2010b[Jerbi, H., Hidouri, M., Glorieux, B., Darriet, J., Garcia, A., Jubera, V. & Ben Amara, M. (2010b). J. Solid State Chem. 183, 1752-1760.], 2012[Jerbi, H., Hidouri, M. & Ben Amara, M. (2012). Acta Cryst. E68, i44.]).

As a contribution to the investigation of the above-mentioned systems, we report here the structural characterization of a new magnesium phosphate Na3RbMg7(PO4)6, which is, to our knowledge, the first magnesium phosphate revealing an original structure for an atomic ratio Mg/P equal to 7/6.

2. Structural commentary

To the best of our knowledge, Na3RbMg7(PO4)6 exhibits a new structure type. A projection along the [010] direction of its structure (Fig. 1[link]) clearly evidences the three-dimensional character of its anionic framework, which is built up from five different polyhedra MgOx (x = 5, 6) and three kinds of PO4 tetra­hedra connected together by sharing edges and corners. The Na+ cations are located within channels running along the [010] direction while the Rb+ cations are found in the large inter­stitial cavities.

[Figure 1]
Figure 1
A view of the Na3RbMg7(PO4)6 structure along [010]. Colour key: MgOx (x = 5 and 6; blue polyhedra), PO4 (purple polyhedra), Rb (green spheres) and Na (yellow spheres).

A projection of the structure on the (012) plane (Fig. 2[link]) shows that it can also be described on the basis of three kinds of rows (A, B and C) running parallel to the [100] direction. The first row (A; Fig. 3[link]), consists of units with edge-sharing between one Na1O8 and two Na2O6 polyhedra. Such units alternate with Mg1O5 polyhedra, leading to the sequence –Mg1–Na2–Na1–Na2–. The second row (B) consists of corner-sharing P2O4, P3O4, Mg4O6 and Mg5O5 polyhedra, forming the sequence –P3–Mg4–P2–Mg5–. Rows B and B′ are symmetrical with respect to the inversion centre located on the A row. The last row (C) includes units with corner-sharing between P1O4 tetra­hedra and Mg2O10 dimers, which consist of edge-sharing MgiO6 (i = 2, 3) octa­hedra. These units alternate with RbO12 polyhedra to form a –P1–[Mg2,Mg3]–P1–Rb– sequence. These rows, connected to each other through common corners or edges, occur with a sequence of ABCB′.

[Figure 2]
Figure 2
A view down the b axis, showing ABCB' rows made of PO4 tetra­hedra and Mg, Na and Rb atoms.
[Figure 3]
Figure 3
A view of parallel rows of ABC polyhedra.

There are five distinct Mg sites. The Mg1 atom is displaced slightly from the inversion center, statistically occupying two symmetry-related positions. As a consequence, the Mg1O6 polyhedron exhibits two distances that are long [2.241 (5) Å] compared to the other Mg1—O distances, which vary from 1.969 (10) to 2.030 (10) Å. Thus, this environment can be considered as [4 + 1]. The average value of 2.005 (10) Å calculated from the four short distances is slightly higher but consistent with that of 1.930 (2) Å reported for the tetra-coordinated Mg2+ cation in KMgPO4 (Wallez et al.,1998[Wallez, G., Colbeau-Justin, C., Le Mercier, T., Quarton, M. & Robert, F. (1998). J. Solid State Chem. 136, 175-180.]). Sites Mg2 and Mg3 are located on twofold rotation axes and have slightly distorted octa­hedral environments with Mg—O distances varying from 2.052 (3) to 2.202 (2) Å for Mg2 and from 2.042 (2) to 2.169 (2) Å for Mg3. The corresponding average values of 2.123 and 2.103 Å, respectively, are in a good agreement with that of 2.14 Å observed for hexa-coordinated Mg2+ ions in Mg3(PO4)2 (Jaulmes et al., 1997[Jaulmes, S., Elfakir, A., Quarton, M., Brunet, F. & Chopin, C. (1997). J. Solid State Chem. 129, 341-345.]). Site Mg4 is [5 + 1]-coordinated, with five short distances varying from 1.981 (3) to 2.050 (3) Å and a sixth longer distance of 2.5734 (3) Å. A similar environment has already been observed in Mg3(PO4)2 (Jaulmes et al., 1997[Jaulmes, S., Elfakir, A., Quarton, M., Brunet, F. & Chopin, C. (1997). J. Solid State Chem. 129, 341-345.]). Site Mg5 is five-coordinated with Mg—O distances ranging from 2.020 (3) to 2.148 (3) Å. The corresponding mean distance of 2.07 Å is close to that of 2.08 Å observed for Mg2+ with the same coordination in NaMg4(PO4)3 (Ben Amara et al., 1983[Ben Amara, M., Vlasse, M., Olazcuaga, R., Le Flem, G. & Hagenmuller, P. (1983). Acta Cryst. C39, 936-939.]). The P—O distances within the PO4 tetra­hedra are in the range of 1.518 (2)–1.552 (2) Å with an overall mean value of 1.539 Å, very close to that of 1.537 Å predicted by Baur (1974[Baur, W. H. (1974). Acta Cryst. B30, 1195-1215.]) for monophosphate groups.

The environments of the alkali cations are shown in Fig. 4[link]. Those of the two crystallographic distinct Na sites were determined assuming a maximum sodium–oxygen distance Lmax of 3.13 Å, as suggested by Donnay & Allmann (1970[Donnay, G. & Allmann, R. (1970). Am. Mineral. 55, 1003-1015.]). As in the case of the Mg1 atom, the sodium atom Na1 is also moved slightly away from the inversion center and statistically occupying two symmetry-related positions. This moving probably occurs to accommodate the environment of the Na1 site, which then consists of eight oxygen atoms with Na—O distances varying from 2.303 (7) to 2.963 (6) Å. Na2 is bound to only six oxygen atoms, with Na2—O distances in the range 2.246 (3)–2.962 (3) Å. The Rb+ ion is located on a twofold rotation axis and occupies a single site whose environment was determined assuming all Rb—O distances to be shorter than the shortest distance between Rb+ and its nearest cation. This environment then consists of twelve oxygen atoms with Rb—O distances ranging from 2.923 (3) to 3.517 (2) Å.

[Figure 4]
Figure 4
The environment of the (a) Na1+, (b) Na2+ and (c) Rb+ cations, showing displacement ellipsoids drawn at the 50% probability level.

3. Synthesis and crystallization

Single crystals of Na3RbMg7(PO4)6 were grown in a flux of sodium molybdate, Na2MoO4, with a P:Mo atomic ratio of 2:1. Appropriate amounts of the starting reactants (NH4)H2PO4, Na2CO3, Rb2CO3, (MgCO3)4Mg(OH)2·5H2O and Na2MoO4·2H2O were dissolved in nitric acid and the obtained solution was evaporated to dryness. The residue was homogenized by grinding in an agate mortar, and subsequently heated in a platinum crucible for 24 h at 673 K and then for 12 h at 873 K. After being reground, the sample was melted for 2 h at 1273 K and then cooled slowly down to room temperature at a rate of 10 K h−1. The solidified melt was washed with boiling water to dissolve the flux. Colourless, irregularly shaped crystals were extracted from the final product.

4. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1[link]. The refinement was performed on the basis of electric neutrality and similar works. The atomic positions are determined by comparison with the refinements reported by Jerbi et al. (2010a[Jerbi, H., Hidouri, M. & Ben Amara, M. (2010a). J. Rare Earths, 28, 481-487.]) and McCoy et al. (1994[McCoy, T. J., Steele, I. M., Keil, K., Leonard, B. F. & Endress, M. (1994). Am. Mineral. 79, 375-380.]).

Table 1
Experimental details

Crystal data
Chemical formula Na3RbMg7(PO4)6
Mr 894.43
Crystal system, space group Monoclinic, C2/c
Temperature (K) 293
a, b, c (Å) 12.734 (3), 10.685 (3), 15.498 (5)
β (°) 112.83 (2)
V3) 1943.5 (10)
Z 4
Radiation type Mo Kα
μ (mm−1) 3.47
Crystal size (mm) 0.16 × 0.10 × 0.07
 
Data collection
Diffractometer Enraf–Nonius Turbo CAD-4
Absorption correction Part of the refinement model (ΔF) (Parkin et al., 1995[Parkin, S., Moezzi, B. & Hope, H. (1995). J. Appl. Cryst. 28, 53-56.])
Tmin, Tmax 0.377, 0.485
No. of measured, independent and observed [I > 2σ(I)] reflections 2333, 2333, 1968
Rint 0.020
(sin θ/λ)max−1) 0.660
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.036, 0.100, 1.07
No. of reflections 2333
No. of parameters 196
Δρmax, Δρmin (e Å−3) 0.87, −1.49
Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1994[Enraf-Nonius (1994). CAD-4 EXPRESS. Enraf-Nonius, Delft, The Net.]), XCAD4 (Harms & Wocadlo, 1995[Harms, K. & Wocadlo, S. (1995). XCAD4. University of Marburg, Germany.]), SIR92 (Altomare et al., 1993[Altomare, A., Cascarano, G., Giacovazzo, C. & Guagliardi, A. (1993). J. Appl. Cryst. 26, 343-350.]), SHELXL2014 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), DIAMOND (Brandenburg et al., 1999[Brandenburg, K. (1999). DIAMOND. University of Bonn, Germany.]) and WinGX (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]).

Supporting information


Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: DIAMOND (Brandenburg et al., 1999); software used to prepare material for publication: WinGX (Farrugia, 2012).

Trisodium rubidium heptamagnesium hexakis(orthophosphate) top
Crystal data top
Mg7Na3O24P6RbF(000) = 1744
Mr = 894.43Dx = 3.057 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
a = 12.734 (3) ÅCell parameters from 25 reflections
b = 10.685 (3) Åθ = 7.5–10.8°
c = 15.498 (5) ŵ = 3.47 mm1
β = 112.83 (2)°T = 293 K
V = 1943.5 (10) Å3Prism, colourless
Z = 40.16 × 0.10 × 0.07 mm
Data collection top
Enraf–Nonius Turbo CAD-4
diffractometer
Rint = 0.020
non–profiled ω/2τ scansθmax = 28.0°, θmin = 2.6°
Absorption correction: part of the refinement model (ΔF)
(Parkin et al., 1995)
h = 1615
Tmin = 0.377, Tmax = 0.485k = 014
2333 measured reflectionsl = 020
2333 independent reflections2 standard reflections every 60 min
1968 reflections with I > 2σ(I) intensity decay: 2%
Refinement top
Refinement on F2196 parameters
Least-squares matrix: full0 restraints
R[F2 > 2σ(F2)] = 0.036 w = 1/[σ2(Fo2) + (0.0549P)2 + 7.6361P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.100(Δ/σ)max < 0.001
S = 1.07Δρmax = 0.87 e Å3
2333 reflectionsΔρmin = 1.49 e Å3
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
xyzUiso*/UeqOcc. (<1)
Rb0.50000.74607 (5)0.75000.02406 (16)
Na10.2552 (5)0.7550 (6)0.0226 (3)0.0279 (12)0.5
Na20.01858 (14)0.76242 (14)0.98277 (13)0.0226 (4)
Mg10.2487 (8)0.2471 (9)0.0142 (4)0.0098 (10)0.5
Mg20.00000.58859 (15)0.75000.0071 (3)
Mg30.50000.62142 (14)0.25000.0059 (3)
Mg40.18422 (9)0.54259 (10)0.12717 (7)0.0065 (2)
Mg50.19042 (9)0.99696 (11)0.14183 (7)0.0081 (2)
P10.28980 (7)0.76938 (7)0.27439 (6)0.00668 (18)
O110.41297 (19)0.7658 (2)0.27801 (17)0.0097 (5)
O120.25429 (18)0.9074 (2)0.27435 (15)0.0084 (4)
O130.2043 (2)0.7106 (3)0.18543 (18)0.0164 (5)
O140.2884 (2)0.6963 (2)0.36018 (17)0.0146 (5)
P20.41165 (6)0.50005 (7)0.08098 (5)0.00531 (18)
O210.53692 (18)0.5150 (2)0.15135 (15)0.0084 (4)
O220.38853 (19)0.5698 (2)0.98959 (16)0.0113 (5)
O230.34627 (19)0.5654 (2)0.13363 (15)0.0085 (4)
O240.38345 (19)0.3619 (2)0.06370 (17)0.0119 (5)
P30.09357 (6)0.50198 (7)0.92791 (5)0.00484 (18)
O310.03126 (18)0.4851 (2)0.86059 (16)0.0100 (5)
O320.10990 (18)0.6126 (2)0.99444 (15)0.0103 (5)
O330.15211 (18)0.5301 (2)0.85956 (16)0.0109 (5)
O340.1418 (2)0.3884 (2)0.99025 (18)0.0136 (5)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Rb0.0278 (3)0.0250 (3)0.0200 (3)0.0000.0099 (2)0.000
Na10.0132 (16)0.0218 (17)0.050 (4)0.0034 (12)0.014 (3)0.009 (3)
Na20.0180 (8)0.0166 (7)0.0412 (10)0.0006 (6)0.0202 (7)0.0027 (6)
Mg10.0043 (9)0.0081 (11)0.015 (3)0.0002 (8)0.001 (2)0.001 (3)
Mg20.0052 (7)0.0109 (7)0.0054 (7)0.0000.0021 (5)0.000
Mg30.0044 (7)0.0099 (7)0.0050 (6)0.0000.0037 (5)0.000
Mg40.0035 (5)0.0114 (5)0.0052 (5)0.0010 (4)0.0024 (4)0.0014 (4)
Mg50.0036 (5)0.0166 (6)0.0055 (5)0.0009 (4)0.0033 (4)0.0002 (4)
P10.0030 (3)0.0093 (4)0.0098 (4)0.0003 (3)0.0046 (3)0.0010 (3)
O110.0045 (10)0.0115 (11)0.0158 (11)0.0007 (8)0.0070 (9)0.0000 (9)
O120.0059 (10)0.0106 (11)0.0097 (11)0.0019 (8)0.0042 (9)0.0004 (8)
O130.0076 (11)0.0216 (13)0.0179 (12)0.0027 (10)0.0026 (9)0.0117 (11)
O140.0149 (12)0.0142 (12)0.0203 (13)0.0005 (10)0.0129 (10)0.0051 (10)
P20.0029 (4)0.0105 (4)0.0038 (4)0.0006 (3)0.0028 (3)0.0011 (3)
O210.0027 (10)0.0169 (11)0.0056 (10)0.0002 (8)0.0017 (8)0.0028 (8)
O220.0098 (11)0.0191 (12)0.0060 (10)0.0007 (9)0.0043 (9)0.0011 (9)
O230.0065 (10)0.0139 (11)0.0072 (10)0.0000 (8)0.0049 (8)0.0026 (9)
O240.0081 (11)0.0112 (11)0.0165 (12)0.0023 (9)0.0049 (9)0.0042 (9)
P30.0025 (4)0.0090 (4)0.0040 (4)0.0005 (3)0.0024 (3)0.0008 (3)
O310.0027 (10)0.0181 (12)0.0089 (11)0.0016 (9)0.0018 (8)0.0003 (9)
O320.0091 (11)0.0144 (11)0.0082 (11)0.0003 (9)0.0041 (9)0.0034 (9)
O330.0044 (10)0.0232 (12)0.0066 (10)0.0001 (9)0.0037 (8)0.0014 (9)
O340.0093 (11)0.0141 (11)0.0197 (12)0.0061 (9)0.0080 (9)0.0088 (10)
Geometric parameters (Å, º) top
Rb—O24i2.923 (3)Mg2—O33xvi2.115 (2)
Rb—O24ii2.923 (3)Mg2—O332.115 (2)
Rb—O13iii3.163 (3)Mg2—O312.202 (2)
Rb—O13iv3.163 (3)Mg2—O31xvi2.202 (2)
Rb—O31v3.186 (2)Mg3—O112.042 (2)
Rb—O31vi3.186 (2)Mg3—O11xvii2.042 (2)
Rb—O21i3.301 (2)Mg3—O212.100 (2)
Rb—O21ii3.301 (2)Mg3—O21xvii2.100 (2)
Rb—O14iii3.452 (3)Mg3—O23xvii2.169 (2)
Rb—O14iv3.452 (3)Mg3—O232.169 (2)
Rb—O12iv3.517 (2)Mg4—O131.981 (3)
Rb—O12iii3.517 (2)Mg4—O12xv2.026 (3)
Na1—O32vii2.303 (7)Mg4—O232.041 (2)
Na1—O32iv2.318 (7)Mg4—O32vii2.043 (3)
Na1—O22iv2.573 (7)Mg4—O31xviii2.050 (2)
Na1—O232.620 (7)Mg4—O34vii2.573 (3)
Na1—O22vii2.782 (7)Mg5—O22iv2.020 (3)
Na1—O132.878 (5)Mg5—O21xix2.026 (2)
Na1—O33iv2.886 (6)Mg5—O33iv2.034 (2)
Na1—O23viii2.963 (6)Mg5—O122.121 (3)
Na2—O322.246 (3)Mg5—O14xx2.148 (3)
Na2—O24ix2.340 (3)P1—O131.521 (3)
Na2—O22x2.365 (3)P1—O121.542 (2)
Na2—O34xi2.396 (3)P1—O111.548 (2)
Na2—O14xii2.495 (3)P1—O141.548 (2)
Na2—O11xii2.962 (3)P2—O241.518 (2)
Mg1—O34vii1.969 (10)P2—O22vii1.524 (2)
Mg1—O242.004 (10)P2—O231.541 (2)
Mg1—O24xiii2.017 (10)P2—O211.552 (2)
Mg1—O34xiv2.030 (10)P3—O341.524 (2)
Mg1—O14xv2.241 (4)P3—O321.528 (2)
Mg2—O11iv2.052 (3)P3—O311.537 (2)
Mg2—O11xii2.052 (3)P3—O331.543 (2)
O24i—Rb—O24ii133.51 (9)O24ix—Na2—O22x92.29 (10)
O24i—Rb—O13iii84.83 (7)O32—Na2—O34xi90.71 (10)
O24ii—Rb—O13iii101.86 (7)O24ix—Na2—O34xi71.97 (10)
O24i—Rb—O13iv101.86 (7)O22x—Na2—O34xi159.77 (12)
O24ii—Rb—O13iv84.83 (7)O32—Na2—O14xii131.25 (11)
O13iii—Rb—O13iv163.19 (10)O24ix—Na2—O14xii75.82 (9)
O24i—Rb—O31v136.57 (6)O22x—Na2—O14xii114.69 (10)
O24ii—Rb—O31v84.63 (6)O34xi—Na2—O14xii74.54 (9)
O13iii—Rb—O31v110.05 (7)O32—Na2—O11xii85.19 (9)
O13iv—Rb—O31v54.74 (6)O24ix—Na2—O11xii128.61 (10)
O24i—Rb—O31vi84.63 (6)O22x—Na2—O11xii99.52 (9)
O24ii—Rb—O31vi136.57 (6)O34xi—Na2—O11xii100.27 (10)
O13iii—Rb—O31vi54.74 (6)O14xii—Na2—O11xii53.75 (8)
O13iv—Rb—O31vi110.05 (7)O34vii—Mg1—O2491.7 (4)
O31v—Rb—O31vi73.42 (9)O34vii—Mg1—O24xiii88.6 (4)
O24i—Rb—O21i47.00 (6)O24—Mg1—O24xiii166.9 (2)
O24ii—Rb—O21i90.86 (6)O34vii—Mg1—O34xiv167.0 (2)
O13iii—Rb—O21i72.22 (6)O24—Mg1—O34xiv87.2 (4)
O13iv—Rb—O21i123.54 (6)O24xiii—Mg1—O34xiv89.6 (4)
O31v—Rb—O21i175.28 (6)O34vii—Mg1—O14xv89.2 (3)
O31vi—Rb—O21i110.99 (6)O24—Mg1—O14xv104.7 (3)
O24i—Rb—O21ii90.86 (6)O24xiii—Mg1—O14xv88.4 (3)
O24ii—Rb—O21ii47.00 (6)O34xiv—Mg1—O14xv103.6 (3)
O13iii—Rb—O21ii123.54 (6)O11iv—Mg2—O11xii81.37 (14)
O13iv—Rb—O21ii72.22 (7)O11iv—Mg2—O33xvi117.11 (10)
O31v—Rb—O21ii110.99 (6)O11xii—Mg2—O33xvi89.56 (10)
O31vi—Rb—O21ii175.28 (6)O11iv—Mg2—O3389.56 (10)
O21i—Rb—O21ii64.66 (8)O11xii—Mg2—O33117.11 (10)
O24i—Rb—O14iii126.45 (6)O33xvi—Mg2—O33145.64 (16)
O24ii—Rb—O14iii63.05 (6)O11iv—Mg2—O31145.19 (10)
O13iii—Rb—O14iii44.16 (6)O11xii—Mg2—O3186.60 (9)
O13iv—Rb—O14iii131.70 (6)O33xvi—Mg2—O3195.21 (10)
O31v—Rb—O14iii85.51 (6)O33—Mg2—O3167.21 (9)
O31vi—Rb—O14iii78.00 (6)O11iv—Mg2—O31xvi86.60 (9)
O21i—Rb—O14iii93.70 (6)O11xii—Mg2—O31xvi145.19 (10)
O21ii—Rb—O14iii103.71 (6)O33xvi—Mg2—O31xvi67.21 (9)
O24i—Rb—O14iv63.05 (6)O33—Mg2—O31xvi95.20 (9)
O24ii—Rb—O14iv126.45 (6)O31—Mg2—O31xvi119.70 (14)
O13iii—Rb—O14iv131.70 (6)O11—Mg3—O11xvii81.88 (14)
O13iv—Rb—O14iv44.16 (6)O11—Mg3—O21149.00 (10)
O31v—Rb—O14iv78.00 (6)O11xvii—Mg3—O2187.76 (9)
O31vi—Rb—O14iv85.51 (6)O11—Mg3—O21xvii87.76 (9)
O21i—Rb—O14iv103.71 (6)O11xvii—Mg3—O21xvii149.00 (10)
O21ii—Rb—O14iv93.70 (6)O21—Mg3—O21xvii114.43 (14)
O14iii—Rb—O14iv159.44 (9)O11—Mg3—O23xvii114.89 (10)
O24i—Rb—O12iv67.45 (6)O11xvii—Mg3—O23xvii89.77 (9)
O24ii—Rb—O12iv90.89 (6)O21—Mg3—O23xvii94.09 (9)
O13iii—Rb—O12iv150.50 (6)O21xvii—Mg3—O23xvii68.28 (9)
O13iv—Rb—O12iv42.77 (6)O11—Mg3—O2389.77 (9)
O31v—Rb—O12iv97.43 (6)O11xvii—Mg3—O23114.89 (10)
O31vi—Rb—O12iv128.18 (6)O21—Mg3—O2368.28 (9)
O21i—Rb—O12iv81.20 (5)O21xvii—Mg3—O2394.09 (9)
O21ii—Rb—O12iv50.59 (5)O23xvii—Mg3—O23147.97 (14)
O14iii—Rb—O12iv153.49 (6)O13—Mg4—O12xv111.06 (11)
O14iv—Rb—O12iv43.24 (6)O13—Mg4—O2385.41 (10)
O24i—Rb—O12iii90.89 (6)O12xv—Mg4—O2387.74 (10)
O24ii—Rb—O12iii67.45 (6)O13—Mg4—O32vii93.13 (12)
O13iii—Rb—O12iii42.77 (6)O12xv—Mg4—O32vii155.80 (11)
O13iv—Rb—O12iii150.50 (6)O23—Mg4—O32vii94.02 (10)
O31v—Rb—O12iii128.18 (6)O13—Mg4—O31xviii92.75 (11)
O31vi—Rb—O12iii97.43 (6)O12xv—Mg4—O31xviii86.03 (10)
O21i—Rb—O12iii50.59 (5)O23—Mg4—O31xviii172.38 (11)
O21ii—Rb—O12iii81.20 (5)O32vii—Mg4—O31xviii93.46 (10)
O14iii—Rb—O12iii43.24 (6)O13—Mg4—O34vii154.80 (11)
O14iv—Rb—O12iii153.49 (6)O12xv—Mg4—O34vii93.48 (10)
O12iv—Rb—O12iii124.43 (8)O23—Mg4—O34vii90.10 (9)
O32vii—Na1—O32iv163.38 (18)O32vii—Mg4—O34vii62.42 (9)
O32vii—Na1—O22iv88.3 (2)O31xviii—Mg4—O34vii94.64 (9)
O32iv—Na1—O22iv94.9 (3)O22iv—Mg5—O21xix89.44 (10)
O32vii—Na1—O2374.4 (2)O22iv—Mg5—O33iv92.64 (10)
O32iv—Na1—O23112.8 (3)O21xix—Mg5—O33iv175.75 (11)
O22iv—Na1—O23137.03 (19)O22iv—Mg5—O12132.14 (11)
O32vii—Na1—O22vii89.9 (2)O21xix—Mg5—O1289.48 (10)
O32iv—Na1—O22vii83.2 (2)O33iv—Mg5—O1286.38 (10)
O22iv—Na1—O22vii166.37 (17)O22iv—Mg5—O14xx110.57 (11)
O23—Na1—O22vii54.84 (15)O21xix—Mg5—O14xx92.12 (10)
Na1viii—Na1—O13150.6 (12)O33iv—Mg5—O14xx90.63 (10)
O32vii—Na1—O1367.64 (15)O12—Mg5—O14xx117.28 (10)
O32iv—Na1—O13129.0 (2)O13—P1—O12106.71 (14)
O22iv—Na1—O1377.79 (16)O13—P1—O11112.40 (14)
O23—Na1—O1359.29 (12)O12—P1—O11108.47 (12)
O22vii—Na1—O13113.9 (2)O13—P1—O14109.11 (15)
O32vii—Na1—O33iv138.3 (2)O12—P1—O14112.44 (13)
O32iv—Na1—O33iv56.44 (15)O11—P1—O14107.79 (13)
O22iv—Na1—O33iv64.67 (16)O24—P2—O22vii111.34 (14)
O23—Na1—O33iv103.37 (17)O24—P2—O23113.25 (13)
O22vii—Na1—O33iv123.6 (2)O22vii—P2—O23108.74 (13)
O13—Na1—O33iv75.63 (12)O24—P2—O21109.41 (13)
O32vii—Na1—O23viii102.1 (2)O22vii—P2—O21112.20 (13)
O32iv—Na1—O23viii67.63 (16)O23—P2—O21101.56 (12)
O22iv—Na1—O23viii52.91 (14)O34—P3—O32105.79 (14)
O23—Na1—O23viii168.2 (2)O34—P3—O31113.15 (14)
O22vii—Na1—O23viii114.48 (15)O32—P3—O31112.52 (13)
O13—Na1—O23viii130.4 (2)O34—P3—O33114.02 (13)
O33iv—Na1—O23viii86.8 (2)O32—P3—O33109.69 (14)
O32—Na2—O24ix143.52 (12)O31—P3—O33101.82 (13)
O32—Na2—O22x95.11 (10)
Symmetry codes: (i) x, y+1, z+1/2; (ii) x+1, y+1, z+1; (iii) x+1/2, y+3/2, z+1/2; (iv) x+1/2, y+3/2, z+1; (v) x+1/2, y+1/2, z; (vi) x+1/2, y+1/2, z+3/2; (vii) x, y, z1; (viii) x+1/2, y+3/2, z; (ix) x1/2, y+1/2, z+1; (x) x+1/2, y+3/2, z+2; (xi) x, y+1, z+2; (xii) x1/2, y+3/2, z+1/2; (xiii) x+1/2, y+1/2, z; (xiv) x+1/2, y+1/2, z+1; (xv) x+1/2, y1/2, z+1/2; (xvi) x, y, z+3/2; (xvii) x+1, y, z+1/2; (xviii) x, y+1, z+1; (xix) x1/2, y+1/2, z; (xx) x+1/2, y+1/2, z+1/2.
 

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