Crystal structure of alluaudite-type NaMg3(HPO4)2(PO4)

Ould Saleck, A.; Assani, A.; Saadi, M.; Mercier, C.; Follet, C.; El Ammari, L.

doi:10.1107/S205698901501155X

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Volume 71| Part 7| July 2015| Pages 813-815

doi:10.1107/S205698901501155X

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Crystal structure of alluaudite-type NaMg₃(HPO₄)₂(PO₄)

Ahmed Ould Saleck,^a,^b ^* Abderrazzak Assani,^a Mohamed Saadi,^a Cyrille Mercier,^b Claudine Follet ^b and Lahcen El Ammari ^a

^aLaboratoire de Chimie du Solide Appliquée, Faculté des Sciences, Université Mohammed V, Avenue Ibn Battouta, BP 1014, Rabat, Morocco, and ^bLaboratoire des Matériaux Céramiques et Procédés Associés, EA2443, Université de Valenciennes et du Hainaut-Cambrésis, Boulevard Charles de Gaulle, BP 59600, Maubeuge, France
^*Correspondence e-mail: a_ouldsaleck@yahoo.fr

Edited by M. Weil, Vienna University of Technology, Austria (Received 8 June 2015; accepted 15 June 2015; online 20 June 2015)

The title compound, sodium trimagnesium bis(hydrogen phosphate) phosphate, was obtained under hydrothermal conditions. In the crystal, two types of [MgO₆] octahedra, one with point group symmetry 2, share edges to build chains extending parallel to [10-1]. These chains are linked together by two kinds of phosphate tetrahedra, HPO₄ and PO₄, the latter with point group symmetry 2. The three-dimensional framework delimits two different types of channels extending along [001]. One channel hosts the Na⁺ cations (site symmetry 2) surrounded by eight O atoms, with Na—O bond lengths varying between 2.2974 (13) and 2.922 (2) Å. The OH group of the HPO₄ tetrahedron points into the other type of channel and exhibits a strong hydrogen bond to an O atom of the PO₄ tetrahedron on the opposite side.

Keywords: crystal structure; transition metal phosphates; alluaudite structure type; hydrothermal synthesis; hydrogen bonding.

CCDC reference: 1406819

1. Chemical context

By means of hydrothermal processes (Demazeau, 2008 ; Yoshimura & Byrappa, 2008 ), we have previously succeeded in the isolation of the mixed-valence manganese phosphates MMn^II₂Mn^III(PO₄)₃ (M = Ba, Pb, Sr) adopting the α-CrPO₄ structure type (Assani et al., 2013 ; Alhakmi et al., 2013a ,b ). In addition, within the pseudo-ternary systems Ag₂O–MO–P₂O₅, hydrothermal syntheses have allowed us to obtain other α-CrPO₄ isotype phosphates, viz. Ag₂M₃(HPO₄)(PO₄)₂ (M = Co, Ni) while AgMg₃(HPO₄)₂(PO₄) is found to adopt the alluaudite structure type (Assani et al., 2011a ,b ,c ). Other hydrothermally grown phosphates with the alluaudite structure include AgCo₃(HPO₄)₂(PO₄) (Guesmi & Driss, 2002 ), AgNi₃(HPO₄)₂(PO₄) (Ben Smail & Jouini, 2002 ), AMn₃(HPO₄)₂(PO₄) (A = Na, Ag) (Leroux et al., 1995a ,b ) and NaCo₃(HPO₄)₂(PO₄) (Lii & Shih, 1994 ). Phosphates belonging to either the α-CrPO₄ or alluaudite structure type or derivatives thereof are still in the focus of research owing to their promising applications as battery materials (Trad et al., 2010 ; Essehli et al., 2015a ,b ; Huang et al., 2015 ).

The crystal structures of alluaudite-type phosphates exhibit channels in which the monovalent cations are localized. Indeed, this is strongly required for conductivity properties. The crystal structure of alluaudite can be formulated by the general formula (A1)(A2)(M1)(M2)₂(PO₄)₃, (Moore & Ito, 1979 ). The two A sites can be occupied by either mono- or divalent medium-sized cations while the two M cationic sites correspond to an octahedral environment generally occupied by transition metal cations. On the basis of literature research, it has been shown that the hydrothermal process allows, in general, stoechiometric phases to be obtained while solid-state reactions give rather a statistical distribution of cations on either the A or M sites, leading to non-stoechiometric compounds (Bouraima et al., 2015 ; Khmiyas et al., 2015 ).

In line with our focus of interest, we hydrothermally synthesized the compound NaMg₃(PO₄)(HPO₄)₂ and report here its crystal structure.

2. Structural commentary

The principal building units of the allaudite structure of the title compound are represented in Fig. 1. The three atoms Mg1, Na1 and P1 are located on a twofold rotation axis (Wyckoff position 4e). Selected interatomic distances are compiled in Table 1. The three-dimensional framework of this structure consists of kinked chains of edge-sharing MgO₆ octahedra running parallel to [10 $[\overline{1}]$ ]. The chains are held together by regular P1O₄ phosphate groups, forming sheets perpendicular to [010], as shown in Fig. 2. The stacked sheets delimit two types of channels along [001]. One of the channels is occupied by Na⁺ cations surrounded by eight oxygen atoms (Table 1), whereas the second channel contains the hydrogen atoms of the HP2O₄ tetrahedra, as shown in Fig. 3. They form strong hydrogen bonds (Table 2, Figs. 1 and 3) with one of the oxygen atoms of PO₄ tetrahedra on opposite sides.

Table 1
Selected bond lengths (Å)

Mg1—O3ⁱ	2.1224 (13)	Na1—O3	2.8840 (19)
Mg1—O1ⁱⁱ	2.1312 (12)	Na1—O1^vii	2.922 (2)
Mg1—O4	2.1669 (14)	P1—O1^viii	1.5372 (12)
Mg2—O6	2.0234 (13)	P1—O1	1.5372 (12)
Mg2—O3ⁱⁱ	2.0686 (13)	P1—O2^viii	1.5476 (13)
Mg2—O2	2.0696 (14)	P1—O2	1.5476 (13)
Mg2—O5ⁱⁱⁱ	2.0729 (13)	P2—O5	1.5234 (12)
Mg2—O5^iv	2.0955 (13)	P2—O6	1.5263 (12)
Mg2—O1^v	2.1153 (14)	P2—O3	1.5349 (13)
Na1—O6	2.2974 (13)	P2—O4	1.5806 (13)
Na1—O6^vi	2.4386 (13)
Symmetry codes: (i) $[x-{\script{1\over 2}}, -y+{\script{1\over 2}}, z-{\script{1\over 2}}]$ ; (ii) $[x, -y+1, z-{\script{1\over 2}}]$ ; (iii) $[-x+{\script{1\over 2}}, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iv) $[x, -y+1, z+{\script{1\over 2}}]$ ; (v) $[-x+{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+1]$ ; (vi) -x+1, -y+1, -z+1; (vii) $[x+{\script{1\over 2}}, -y+{\script{3\over 2}}, z+{\script{1\over 2}}]$ ; (viii) $[-x, y, -z+{\script{1\over 2}}]$ .

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O4—H4⋯O2	0.93	1.57	2.4932 (17)	174

Figure 1
The principal building units in the structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen bonds are indicated by dashed lines [Symmetry codes: (i) x + $[{1\over 2}]$ , y + $[{1\over 2}]$ , z; (ii) −x + $[{3\over 2}]$ , y + $[{1\over 2}]$ , −z + $[{1\over 2}]$ ; (iii) −x + $[{3\over 2}]$ , −y + $[{3\over 2}]$ , −z + 1; (iv) −x + $[{3\over 2}]$ , −y + $[{3\over 2}]$ , −z; (v) −x + 1, −y + 1, −z; (vi) −x + 1, y, −z + $[{1\over 2}]$ ; (vii) x, −y + 1, z + $[{1\over 2}]$ ; (viii) x − $[{1\over 2}]$ , −y + $[{3\over 2}]$ , z − $[{1\over 2}]$ ; (ix) −x + 2, y, −z + $[{3\over 2}]$ ; (x) −x + 2, −y + 1, −z + 1; (xi) x + $[{1\over 2}]$ , −y + $[{1\over 2}]$ , z + $[{1\over 2}]$ ; (xii) −x + $[{3\over 2}]$ , −y + $[{1\over 2}]$ , −z + 1; (xiii) x, −y + 1, z − $[{1\over 2}]$ .]

Figure 2
A sheet resulting from the linkage of kinked chains via vertices of PO₄ tetrahedra.

Figure 3
Polyhedral representation of the NaMg₃(HPO₄)₂(PO₄) structure showing channels along [001]. The O—H⋯O hydrogen bonds are indicated by dashed lines.

3. Synthesis and crystallization

Colourless parallelepiped-shaped crystals of the title compound were grown under hydrothermal conditions, starting from a mixture of Na₄P₂O₇·10H₂O, MgO and H₃PO₄ (85 wt%) in the molar ratio Na₄P₂O₇·10H₂O:MgO:H₃PO₄ = 1:3:3. The hydrothermal reaction was conducted in a 23 ml Teflon-lined autoclave, filled to 50% with distilled water and under autogenous pressure at 483 K for four days.

4. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3. The minimum and maximum electron densities are located 0.71 and 0.17 Å from O5 and H4, respectively. The O–bound H atom was initially located in a difference map and refined with an O—H distance restraint of 0.93 Å, and with U_iso(H) = 1.5U_eq(O).

Table 3
Experimental details

Crystal data
Chemical formula	NaMg₃(HPO₄)₂(PO₄)
M_r	382.85
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	296
a, b, c (Å)	11.8064 (6), 12.0625 (7), 6.4969 (4)
β (°)	113.805 (2)
V (Å³)	846.54 (8)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	1.06
Crystal size (mm)	0.36 × 0.24 × 0.18

Data collection
Diffractometer	Bruker X8 APEX
Absorption correction	Multi-scan (SADABS; Bruker, 2009 )
T_min, T_max	0.504, 0.748
No. of measured, independent and observed [I > 2σ(I)] reflections	9797, 1291, 1138
R_int	0.038
(sin θ/λ)_max (Å⁻¹)	0.714

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.025, 0.072, 1.09
No. of reflections	1291
No. of parameters	88
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.57, −0.54
Computer programs: APEX2 and SAINT (Bruker, 2009), SHELXS (Sheldrick, 2008 ), SHELXL2013 (Sheldrick, 2015 ), ORTEP-3 for Windows (Farrugia, 2012 ). DIAMOND (Brandenburg, 2006 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 1406819

Crystal structure: contains datablock I. DOI: 10.1107/S205698901501155X/wm5174sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S205698901501155X/wm5174Isup2.hkl

checkCIF report

Chemical context top

By means of hydrothermal processes (Demazeau, 2008; Yoshimura & Byrappa, 2008), we have previously succeeded in the isolation of the mixed-valence manganese phosphates MMn^II2Mn^III(PO₄)₃ (M = Ba, Pb, Sr) adopting the α-CrPO₄ structure type (Assani et al., 2013; Alhakmi et al., 2013a,b). In addition, within the pseudo-ternary systems Ag₂O–MO–P₂O₅, hydrothermal syntheses have allowed us to obtain other α-CrPO₄ isotype phosphates, viz. Ag₂M₃(HPO₄)(PO₄)₂ (M = Co, Ni) while AgMg₃(PO₄)(HPO₄)₂ is found to adopt the alluaudite structure type (Assani et al., 2011a,b,c). Other hydrothermally grown phosphates with the alluaudite structure include AgCo₃(HPO₄)₂(PO₄) (Guesmi & Driss, 2002), AgNi₃(HPO₄)₂(PO₄) (Ben Smail & Jouini, 2002), AMn₃(HPO₄)₂(PO₄) (A = Na, Ag) (Leroux et al., 1995a,b) and NaCo₃(HPO₄)₂(PO₄) (Lii & Shih, 1994). Phosphates belonging to either the α-CrPO₄ or alluaudite structure type or derivatives thereof are still in the focus of research owing to their promising applications as battery materials (Trad et al., 2010; Essehli et al., 2015a,b; Huang et al., 2015).

The crystal structures of alluaudite-type phosphates exhibit channels in which the monovalent cations are localized. Indeed, this is strongly required for conductivity properties. The crystal structure of alluaudite can be formulated by the general formula (A1)(A2)(M1)(M2)₂(PO₄)₃, (Moore & Ito, 1979). The two A sites can be occupied by either mono- or divalent medium-sized cations while the two M cationic sites correspond to an octahedral environment generally occupied by transition metal cations. On the basis of literature research, it has been shown that the hydrothermal process allows, in general, stoechiometric phases to be obtained while solid-state reactions give rather a statistical distribution of cations on either the A or M sites, leading to non-stoechiometric compounds (Bouraima et al., 2015; Khmiyas et al., 2015).

In line with our focus of interest, we hydrothermally synthesized the compound NaMg₃(PO₄)(HPO₄)₂ and report here its crystal structure.

Structural commentary top

The principal building units of the allaudite structure of the title compound are represented in Fig. 1. The three atoms Mg1, Na1 and P1 are located on a twofold rotation axis (Wyckoff position 4e). Selected interatomic distances are compiled in Table 1. The three-dimensional framework of this structure consists of kinked chains of edge-sharing MgO₆ octahedra running parallel to [101]. The chains are held together by regular P1O₄ phosphate groups, forming sheets perpendicular to [010], as shown in Fig. 2. The stacked sheets delimit two types of channels along [001]. One of the channels is occupied by Na⁺ cations surrounded by eight oxygen atoms (Table 1), whereas the second channel contains the hydrogen atoms of the HPO₄ tetrahedra, as shown in Fig. 3. They form strong hydrogen bonds (Table 2, Figs. 1 and 3) with one of the oxygen atoms of PO₄ tetrahedra on opposite sides.

Synthesis and crystallization top

Refinement top

Related literature top

For related literature, see: Alhakmi et al. (2013a, 2013b); Assani et al. (2011a, 2011b, 2011c, 2013); Ben & Jouini (2002); Bouraima et al. (2015); Demazeau (2008); Essehli et al. (2015a, 2015b); Guesmi & Driss (2002); Huang et al. (2015); Khmiyas et al. (2015); Lii & Shih (1994); Leroux et al. (1995a, 1995b); Moore & Ito (1979); Trad et al. (2010); Yoshimura & Byrappa (2008).

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS (Sheldrick, 2008); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top

	Fig. 1. The principal building units in the structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen bonds are indicated by dashed lines [Symmetry codes: (i) x + 1/2, y + 1/2, z; (ii) -x + 3/2, y + 1/2, -z + 1/2; (iii) -x + 3/2, -y + 3/2, -z + 1; (iv) -x + 3/2, -y + 3/2, -z; (v) -x + 1, -y + 1, -z; (vi) -x + 1, y, -z + 1/2; (vii) x, -y + 1, z + 1/2; (viii) x - 1/2, -y + 3/2, z - 1/2; (ix) -x + 2, y, -z + 3/2; (x) -x + 2, -y + 1, -z + 1; (xi) x + 1/2, -y + 1/2, z + 1/2; (xii) -x + 3/2, -y + 1/2, -z + 1; (xiii) x, -y + 1, z - 1/2.]
	Fig. 2. A sheet resulting from the linkage of kinked chains via vertices of PO₄ tetrahedra.
	Fig. 3. Polyhedral representation of the NaMg₃(HPO₄)₂(PO₄) structure showing channels along [001]. The O—H···O hydrogen bonds are indicated by dashed lines.

Sodium trimagnesium bis(hydrogen phosphate) phosphate top

Crystal data top

NaMg₃(HPO₄)₂(PO₄)	F(000) = 760
M_r = 382.85	D_x = 3.004 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 11.8064 (6) Å	Cell parameters from 1291 reflections
b = 12.0625 (7) Å	θ = 2.5–30.5°
c = 6.4969 (4) Å	µ = 1.06 mm⁻¹
β = 113.805 (2)°	T = 296 K
V = 846.54 (8) Å³	Block, colourless
Z = 4	0.36 × 0.24 × 0.18 mm

Data collection top

Bruker X8 APEX diffractometer	1291 independent reflections
Radiation source: fine-focus sealed tube	1138 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.038
ϕ and ω scans	θ_max = 30.5°, θ_min = 2.5°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −16→16
T_min = 0.504, T_max = 0.748	k = −17→17
9797 measured reflections	l = −9→8

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F² > 2σ(F²)] = 0.025	H-atom parameters constrained
wR(F²) = 0.072	w = 1/[σ²(F_o²) + (0.0362P)² + 1.4203P] where P = (F_o² + 2F_c²)/3
S = 1.09	(Δ/σ)_max < 0.001
1291 reflections	Δρ_max = 0.57 e Å⁻³
88 parameters	Δρ_min = −0.54 e Å⁻³

Crystal data top

NaMg₃(HPO₄)₂(PO₄)	V = 846.54 (8) Å³
M_r = 382.85	Z = 4
Monoclinic, C2/c	Mo Kα radiation
a = 11.8064 (6) Å	µ = 1.06 mm⁻¹
b = 12.0625 (7) Å	T = 296 K
c = 6.4969 (4) Å	0.36 × 0.24 × 0.18 mm
β = 113.805 (2)°

Data collection top

Bruker X8 APEX diffractometer	1291 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2009)	1138 reflections with I > 2σ(I)
T_min = 0.504, T_max = 0.748	R_int = 0.038
9797 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.025	0 restraints
wR(F²) = 0.072	H-atom parameters constrained
S = 1.09	Δρ_max = 0.57 e Å⁻³
1291 reflections	Δρ_min = −0.54 e Å⁻³
88 parameters

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.

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

	x	y	z	U_iso*/U_eq
Mg1	0.0000	0.27947 (7)	0.2500	0.00857 (18)
Mg2	0.29000 (6)	0.66219 (5)	0.37489 (10)	0.00643 (14)
Na1	0.5000	0.52321 (14)	0.7500	0.0308 (4)
P1	0.0000	0.68659 (5)	0.2500	0.00564 (14)
P2	0.28093 (4)	0.38887 (3)	0.38603 (7)	0.00494 (11)
O1	0.03662 (11)	0.75858 (10)	0.4624 (2)	0.0078 (2)
O2	0.10795 (12)	0.61003 (10)	0.2634 (2)	0.0084 (2)
O3	0.34567 (12)	0.32859 (10)	0.6116 (2)	0.0073 (2)
O4	0.14051 (11)	0.40754 (10)	0.3420 (2)	0.0085 (2)
H4	0.1241	0.4816	0.3033	0.013*
O5	0.28443 (11)	0.32046 (10)	0.1916 (2)	0.0068 (2)
O6	0.34273 (12)	0.50140 (10)	0.4000 (2)	0.0076 (2)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Mg1	0.0081 (4)	0.0088 (4)	0.0094 (4)	0.000	0.0041 (3)	0.000
Mg2	0.0073 (3)	0.0057 (3)	0.0067 (3)	0.0004 (2)	0.0031 (2)	0.0001 (2)
Na1	0.0118 (6)	0.0691 (11)	0.0091 (6)	0.000	0.0016 (5)	0.000
P1	0.0051 (3)	0.0063 (3)	0.0044 (3)	0.000	0.0007 (2)	0.000
P2	0.0060 (2)	0.00431 (19)	0.0043 (2)	−0.00006 (14)	0.00177 (16)	−0.00011 (14)
O1	0.0063 (6)	0.0110 (5)	0.0054 (5)	−0.0010 (4)	0.0014 (5)	−0.0022 (4)
O2	0.0060 (6)	0.0073 (5)	0.0114 (6)	0.0010 (4)	0.0031 (5)	−0.0007 (4)
O3	0.0086 (6)	0.0080 (5)	0.0049 (5)	0.0020 (4)	0.0024 (5)	0.0016 (4)
O4	0.0073 (6)	0.0058 (5)	0.0131 (6)	0.0009 (4)	0.0048 (5)	0.0004 (5)
O5	0.0077 (6)	0.0077 (5)	0.0052 (5)	0.0003 (4)	0.0028 (5)	−0.0009 (4)
O6	0.0083 (6)	0.0051 (5)	0.0093 (6)	−0.0014 (4)	0.0035 (5)	−0.0002 (4)

Geometric parameters (Å, º) top

Mg1—O3ⁱ	2.1224 (13)	Na1—O6^x	2.4386 (13)
Mg1—O3ⁱⁱ	2.1224 (13)	Na1—O3	2.8840 (19)
Mg1—O1ⁱⁱⁱ	2.1312 (12)	Na1—O3^ix	2.8840 (19)
Mg1—O1^iv	2.1312 (12)	Na1—O1^xi	2.922 (2)
Mg1—O4^v	2.1669 (14)	Na1—O1^viii	2.922 (2)
Mg1—O4	2.1669 (14)	P1—O1^v	1.5372 (12)
Mg2—O6	2.0234 (13)	P1—O1	1.5372 (12)
Mg2—O3ⁱⁱⁱ	2.0686 (13)	P1—O2^v	1.5476 (13)
Mg2—O2	2.0696 (14)	P1—O2	1.5476 (13)
Mg2—O5^vi	2.0729 (13)	P2—O5	1.5234 (12)
Mg2—O5^vii	2.0955 (13)	P2—O6	1.5263 (12)
Mg2—O1^viii	2.1153 (14)	P2—O3	1.5349 (13)
Na1—O6	2.2974 (13)	P2—O4	1.5806 (13)
Na1—O6^ix	2.2974 (13)	O4—H4	0.9269
Na1—O6^vii	2.4386 (13)

O3ⁱ—Mg1—O3ⁱⁱ	104.23 (8)	O6^vii—Na1—O6^x	166.01 (10)
O3ⁱ—Mg1—O1ⁱⁱⁱ	86.53 (5)	O6—Na1—O3	56.06 (5)
O3ⁱⁱ—Mg1—O1ⁱⁱⁱ	78.23 (5)	O6^ix—Na1—O3	111.84 (7)
O3ⁱ—Mg1—O1^iv	78.23 (5)	O6^vii—Na1—O3	62.51 (5)
O3ⁱⁱ—Mg1—O1^iv	86.53 (5)	O6^x—Na1—O3	105.27 (6)
O1ⁱⁱⁱ—Mg1—O1^iv	155.13 (8)	O6—Na1—O3^ix	111.84 (7)
O3ⁱ—Mg1—O4^v	83.70 (5)	O6^ix—Na1—O3^ix	56.06 (5)
O3ⁱⁱ—Mg1—O4^v	170.20 (5)	O6^vii—Na1—O3^ix	105.27 (6)
O1ⁱⁱⁱ—Mg1—O4^v	108.38 (5)	O6^x—Na1—O3^ix	62.51 (5)
O1^iv—Mg1—O4^v	89.53 (5)	O3—Na1—O3^ix	71.02 (6)
O3ⁱ—Mg1—O4	170.20 (5)	O6—Na1—O1^xi	118.48 (6)
O3ⁱⁱ—Mg1—O4	83.70 (5)	O6^ix—Na1—O1^xi	74.30 (5)
O1ⁱⁱⁱ—Mg1—O4	89.53 (5)	O6^vii—Na1—O1^xi	84.97 (5)
O1^iv—Mg1—O4	108.38 (5)	O6^x—Na1—O1^xi	107.88 (6)
O4^v—Mg1—O4	89.05 (7)	O3—Na1—O1^xi	146.62 (4)
O6—Mg2—O3ⁱⁱⁱ	85.88 (5)	O3^ix—Na1—O1^xi	129.17 (3)
O6—Mg2—O2	88.80 (5)	O6—Na1—O1^viii	74.30 (5)
O3ⁱⁱⁱ—Mg2—O2	111.03 (6)	O6^ix—Na1—O1^viii	118.48 (7)
O6—Mg2—O5^vi	172.05 (6)	O6^vii—Na1—O1^viii	107.88 (6)
O3ⁱⁱⁱ—Mg2—O5^vi	91.58 (5)	O6^x—Na1—O1^viii	84.97 (5)
O2—Mg2—O5^vi	85.07 (5)	O3—Na1—O1^viii	129.17 (3)
O6—Mg2—O5^vii	98.45 (5)	O3^ix—Na1—O1^viii	146.62 (4)
O3ⁱⁱⁱ—Mg2—O5^vii	162.38 (6)	O1^xi—Na1—O1^viii	51.46 (6)
O2—Mg2—O5^vii	86.23 (5)	O1^v—P1—O1	111.21 (10)
O5^vi—Mg2—O5^vii	86.22 (5)	O1^v—P1—O2^v	111.07 (7)
O6—Mg2—O1^viii	100.87 (6)	O1—P1—O2^v	108.34 (7)
O3ⁱⁱⁱ—Mg2—O1^viii	79.79 (5)	O1^v—P1—O2	108.34 (7)
O2—Mg2—O1^viii	166.18 (6)	O1—P1—O2	111.07 (7)
O5^vi—Mg2—O1^viii	86.06 (5)	O2^v—P1—O2	106.73 (10)
O5^vii—Mg2—O1^viii	82.62 (5)	O5—P2—O6	111.03 (7)
O6—Na1—O6^ix	166.85 (10)	O5—P2—O3	111.42 (7)
O6—Na1—O6^vii	86.56 (4)	O6—P2—O3	108.82 (7)
O6^ix—Na1—O6^vii	91.84 (4)	O5—P2—O4	107.74 (7)
O6—Na1—O6^x	91.84 (4)	O6—P2—O4	108.99 (7)
O6^ix—Na1—O6^x	86.56 (4)	O3—P2—O4	108.78 (7)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4···O2	0.93	1.57	2.4932 (17)	174

Selected bond lengths (Å) top

Mg1—O3ⁱ	2.1224 (13)	Na1—O3	2.8840 (19)
Mg1—O1ⁱⁱ	2.1312 (12)	Na1—O1^vii	2.922 (2)
Mg1—O4	2.1669 (14)	P1—O1^viii	1.5372 (12)
Mg2—O6	2.0234 (13)	P1—O1	1.5372 (12)
Mg2—O3ⁱⁱ	2.0686 (13)	P1—O2^viii	1.5476 (13)
Mg2—O2	2.0696 (14)	P1—O2	1.5476 (13)
Mg2—O5ⁱⁱⁱ	2.0729 (13)	P2—O5	1.5234 (12)
Mg2—O5^iv	2.0955 (13)	P2—O6	1.5263 (12)
Mg2—O1^v	2.1153 (14)	P2—O3	1.5349 (13)
Na1—O6	2.2974 (13)	P2—O4	1.5806 (13)
Na1—O6^vi	2.4386 (13)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O4—H4···O2	0.93	1.57	2.4932 (17)	173.7

Experimental details

Crystal data
Chemical formula	NaMg₃(HPO₄)₂(PO₄)
M_r	382.85
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	296
a, b, c (Å)	11.8064 (6), 12.0625 (7), 6.4969 (4)
β (°)	113.805 (2)
V (Å³)	846.54 (8)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	1.06
Crystal size (mm)	0.36 × 0.24 × 0.18

Data collection
Diffractometer	Bruker X8 APEX diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2009)
T_min, T_max	0.504, 0.748
No. of measured, independent and observed [I > 2σ(I)] reflections	9797, 1291, 1138
R_int	0.038
(sin θ/λ)_max (Å⁻¹)	0.714

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.025, 0.072, 1.09
No. of reflections	1291
No. of parameters	88
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.57, −0.54

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker, 2009), SHELXS (Sheldrick, 2008), SHELXL2013 (Sheldrick, 2015), ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg, 2006), publCIF (Westrip, 2010).

Acknowledgements

The authors thank the Unit of Support for Technical and Scientific Research (UATRS, CNRST) for the X-ray measurements and Mohammed V University, Rabat, Morocco, for financial support.

References

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Volume 71| Part 7| July 2015| Pages 813-815

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