Dilithium manganese(II) catena-tetra­kis­(polyphosphate), Li₂Mn(PO₃)₄

The poly-phosphate Li₂Mn(PO₃)₄ was synthesized and its structure characterized from powder diffraction data by Averbuch-Pouchot & Durif [J. Appl. Cryst. (1972), 5, 307–308]. These authors showed that the structure of this phosphate is isotypic to that of Li₂Cd(PO₃)₄, as confirmed by the present work. The structure is built from infinite zigzag polyphosphate chains, [(PO₃)⁻]_n, extending along [010]. These polyphosphate chains are connected by sharing vertices with MnO₆ octa­hedra (site symmetry .m.) and Li₂O₇ polyhedra, which form also chains parallel to [010]. Adjacent chains are linked by common vertices of polyhedra in such a way as to form porous layers parallel to (100). The three-dimensional framework delimits empty channels extending along [010].

Related literature

For potential applications of lithium and manganese phosphates, see: Parada et al. (2003); Jouini et al. (2003); Bian et al. (2003); Aravindan et al. (2013); Drezen et al. (2007); Bakenov & Taniguchi (2010); Adam et al. (2008). For a previous structure determination from powder data, see: Averbuch-Pouchot & Durif (1972). For the isotypic structure of Li₂Cd(PO₃)₄, see: Averbuch-Pouchot et al. (1976).

Experimental

Crystal data

• Li₂Mn(PO₃)₄

• M_r = 384.70

• Orthorhombic, P n m a

• a = 9.4295 (2) Å

• b = 9.2755 (2) Å

• c = 10.0972 (2) Å

• V = 883.13 (3) ų

• Z = 4

• Mo Kα radiation

• μ = 2.29 mm⁻¹

• T = 296 K

• 0.23 × 0.16 × 0.13 mm

Data collection

• Bruker X8 APEX diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 2008) T_min = 0.651, T_max = 0.743

• 13605 measured reflections

• 2520 independent reflections

• 2318 reflections with I > 2σ(I)

• R_int = 0.024

Refinement

• R[F² > 2σ(F²)] = 0.018

• wR(F²) = 0.051

• S = 1.09

• 2520 reflections

• 97 parameters

• Δρ_max = 0.52 e Å⁻³

• Δρ_min = −0.51 e Å⁻³

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Supporting information

S1. Comment

Due to their interesting physical properties, the lithium and manganese phosphates have a wide domain of applications (Parada et al., 2003; Jouini et al., 2003; Bian et al., 2003). Among these mixed phosphates, the LiMnPO₄ monophosphate is the most studied, followed by the Li₂MnP₂O₇ diphosphate and the Li₂Mn(PO₃)₄ polyphosphate, which is the object of this work. These phosphate materials are being extensively studied as lithium-ion battery electrodes (Aravindan et al., 2013; Drezen et al., 2007; Bakenov & Taniguchi, 2010; Adam et al., 2008).

Averbuch-Pouchot & Durif (1972) have synthesized the powder of the polyphosphate Li₂Mn(PO₃)₄ and have shown that the structure of this phosphate is isotype to that of Li₂Cd(PO₃)₄ (Averbuch-Pouchot et al., 1976). The present paper describes the crystal structure of the title compound from single-crystal X-ray diffraction data.

The partial three-dimensional plot in Fig.1 illustrates the connection ion-oxygen polyhedra in the crystal structure of the title compound. The phosphorous atoms have a tetrahedral environment with P–O distances varying between 1.4650 (9) Å and 1.5932 (7) Å and the angles O–P–O are in the range of 95.22 (5)–119.93 (5) °. These value are within the limits generally observed in the crystal chemistry of condensed phosphate. The Mn2+ cation is surrounded by a roughly octahedral arrangement of six oxygen atoms and share one edge with Li₂O₇ polyhedron in which each Li is coordinated to five oxygen atoms.

The structure of Li₂Mn(PO₃)₄ consists of edge-sharing [MnO₆] octahedra and [Li₂O₇] polyhedra forming an infinite linear chains [Mn–Li–Li–Mn] running parallel to [100], as shown in Fig.2. The (PO₃)^-n polyphosphate form also infinite zigzag chains propaging along b axis. Adjacent chains are linked together by common vertices of polyhedra in such a way as to form porous layers parallel to (100). The resulting 3-D framework presents empty tunnels running along [010] directions (Fig.2).

Related literature

For potential applications of lithium and manganese phosphates, see: Parada et al. (2003); Jouini et al. (2003); Bian et al. (2003); Aravindan et al. (2013); Drezen et al. (2007); Bakenov & Taniguchi (2010); Adam et al. (2008). For a previous structure determination from powder data, see: Averbuch-Pouchot & Durif (1972). For the isotypic structure of Li₂Cd(PO₃)₄, see: Averbuch-Pouchot et al. (1976).

S2. Experimental

The synthesis of the polyphosphate Li₂MnP₄O₁₂ by wet process, was made starting from the stoechiometric proportions of (LiNO₃ 99,9%) (I); (Mn(NO₃)₂,4H₂O 99%) (II) and ((NH₄)₂HPO₄ 99%) (III). The starting reagents were made in distilled water solution. A drop by drop of the solution (II) was added on the solution (I), under mechanical agitation, and thereafter the solution (III). The mixture is carried to 373 K until total evaporation of the solution. The residue thus obtained was heated in air, intersected with grindings, until a final temperature of 773 K during 4 h. The final products are of violet colour.

The previous powder of the Li₂MnP₄O₁₂ phase synthesized by wet process introduced into a platinum crucible, then carried gradually heated at a temperature higher than its melting point (973 K) during 2 h, followed-up by a slow cooling about 5 °K per hour until 773 K. Then, the power supply of the furnace is cut, and cooling is continued until the ambient temperature. The single crystals obtained are of violet colour.

S3. Refinement

The highest peak and the deepest hole in the final Fourier map are at 0.51 Å and 0.97 Å, from O3 and P1, respectively. The not significant bonds and angles were removed from the CIF file.

Computing details

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures

	Fig. 1. Plot of Li2Mn(PO3)4 crystal structure showing polyhedra linkage. Displacement ellipsoids are drawn at the 50% probability level. Symmetry codes:(i) x - 1/2, y, -z + 3/2; (ii) x - 1/2, -y + 1/2, -z + 3/2; (iii) x, -y + 1/2, z; (iv) -x + 1/2, y + 1/2, z + 1/2; (v) -x + 1/2, -y, z + 1/2; (vi) x - 1/2, y, -z + 1/2; (vii) -x, -y, -z + 1; (viii) -x + 1/2, -y, z - 1/2.
	Fig. 2. Three-dimensional views of the Li2Mn(PO3)4 framework structure showing emptly tunnels running along b.

Dilithium manganese(II) catena-tetrakis(polyphosphate)

Crystal data

Li2Mn(PO3)4	F(000) = 748
Mr = 384.70	Dx = 2.893 Mg m^−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 2520 reflections
a = 9.4295 (2) Å	θ = 3.0–38.1°
b = 9.2755 (2) Å	µ = 2.29 mm^−1
c = 10.0972 (2) Å	T = 296 K
V = 883.13 (3) Å^3	Block, violet
Z = 4	0.23 × 0.16 × 0.13 mm

Data collection

Bruker X8 APEX diffractometer	2520 independent reflections
Radiation source: fine-focus sealed tube	2318 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.024
φ and ω scans	θmax = 38.1°, θmin = 3.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 2008)	h = −16→13
Tmin = 0.651, Tmax = 0.743	k = −16→13
13605 measured reflections	l = −11→17

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Primary atom site location: structure-invariant direct methods
R[F^2 > 2σ(F^2)] = 0.018	Secondary atom site location: difference Fourier map
wR(F^2) = 0.051	w = 1/[σ^2(Fo^2) + (0.0262P)^2 + 0.2295P] where P = (Fo^2 + 2Fc^2)/3
S = 1.09	(Δ/σ)max = 0.001
2520 reflections	Δρmax = 0.52 e Å^−3
97 parameters	Δρmin = −0.51 e Å^−3

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.

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

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

	x	y	z	Uiso*/Ueq
Mn1	0.012320 (17)	0.2500	0.697042 (16)	0.00824 (4)
P1	0.30533 (3)	0.2500	0.39321 (3)	0.00708 (5)
P2	0.29220 (2)	0.03744 (2)	0.610286 (19)	0.00742 (4)
P3	0.22718 (3)	0.2500	0.98429 (3)	0.00661 (5)
O1	0.14967 (9)	0.2500	0.37467 (9)	0.01356 (15)
O2	0.40037 (9)	0.2500	0.27630 (8)	0.01232 (14)
O3	0.35189 (7)	0.11634 (8)	0.48227 (7)	0.01946 (13)
O4	0.13548 (6)	0.05951 (7)	0.62027 (6)	0.01146 (10)
O5	0.38358 (7)	0.07235 (7)	0.72611 (7)	0.01537 (11)
O6	0.32753 (6)	−0.12374 (7)	0.57702 (7)	0.01270 (10)
O7	0.14661 (10)	0.2500	0.86024 (9)	0.01801 (18)
O8	0.38557 (9)	0.2500	0.98024 (8)	0.01291 (15)
Li1	0.0036 (2)	0.1031 (3)	0.3305 (3)	0.0319 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Mn1	0.00776 (6)	0.00889 (7)	0.00807 (7)	0.000	−0.00102 (5)	0.000
P1	0.00667 (10)	0.00812 (11)	0.00646 (10)	0.000	0.00036 (7)	0.000
P2	0.00715 (7)	0.00576 (8)	0.00935 (8)	−0.00010 (5)	0.00026 (5)	−0.00046 (6)
P3	0.00626 (10)	0.00710 (11)	0.00645 (10)	0.000	−0.00036 (7)	0.000
O1	0.0071 (3)	0.0192 (4)	0.0144 (3)	0.000	−0.0017 (3)	0.000
O2	0.0121 (3)	0.0163 (4)	0.0086 (3)	0.000	0.0034 (3)	0.000
O3	0.0135 (2)	0.0205 (3)	0.0243 (3)	0.0064 (2)	0.0071 (2)	0.0153 (3)
O4	0.0076 (2)	0.0110 (2)	0.0158 (2)	0.00088 (18)	0.00164 (17)	−0.0008 (2)
O5	0.0134 (2)	0.0165 (3)	0.0162 (3)	−0.0019 (2)	−0.0040 (2)	−0.0070 (2)
O6	0.0125 (2)	0.0068 (2)	0.0188 (3)	0.00120 (18)	−0.0044 (2)	−0.0039 (2)
O7	0.0158 (4)	0.0279 (5)	0.0103 (3)	0.000	−0.0058 (3)	0.000
O8	0.0065 (3)	0.0222 (4)	0.0099 (3)	0.000	0.0015 (2)	0.000
Li1	0.0186 (8)	0.0241 (10)	0.0530 (14)	−0.0087 (7)	−0.0128 (8)	0.0163 (10)

Geometric parameters (Å, º)

Mn1—O7	2.0782 (9)	P2—O3	1.5885 (7)
Mn1—O8^i	2.1523 (8)	P3—O7	1.4650 (9)
Mn1—O5^i	2.1888 (6)	P3—O8	1.4941 (8)
Mn1—O5^ii	2.1888 (6)	P3—O6^iv	1.5857 (6)
Mn1—O4^iii	2.2519 (6)	P3—O6^v	1.5857 (6)
Mn1—O4	2.2519 (6)	Li1—O1	1.988 (2)
P1—O1	1.4797 (9)	Li1—O2^vi	1.992 (2)
P1—O2	1.4821 (9)	Li1—O4^vii	2.060 (2)
P1—O3^iii	1.5932 (7)	Li1—O5^viii	2.211 (3)
P1—O3	1.5932 (7)	Li1—O8^i	2.598 (3)
P2—O5	1.4883 (6)	Li1—Li1^iii	2.725 (5)
P2—O4	1.4953 (6)	Li1—Mn1^vii	3.290 (2)
P2—O6	1.5681 (6)
O7—Mn1—O8^i	176.19 (4)	O5—P2—O6	104.64 (4)
O7—Mn1—O5^i	93.26 (3)	O4—P2—O6	110.79 (4)
O8^i—Mn1—O5^i	89.25 (2)	O5—P2—O3	109.51 (4)
O7—Mn1—O5^ii	93.26 (3)	O4—P2—O3	110.00 (4)
O8^i—Mn1—O5^ii	89.25 (2)	O6—P2—O3	100.93 (4)
O5^i—Mn1—O5^ii	97.67 (4)	O7—P3—O8	119.67 (5)
O7—Mn1—O4^iii	87.63 (2)	O7—P3—O6^iv	109.64 (4)
O8^i—Mn1—O4^iii	90.01 (2)	O8—P3—O6^iv	109.97 (3)
O5^i—Mn1—O4^iii	177.06 (2)	O7—P3—O6^v	109.64 (4)
O5^ii—Mn1—O4^iii	79.48 (2)	O8—P3—O6^v	109.97 (3)
O7—Mn1—O4	87.63 (2)	O6^iv—P3—O6^v	95.22 (5)
O8^i—Mn1—O4	90.01 (2)	O1—Li1—O2^vi	89.50 (9)
O5^i—Mn1—O4	79.48 (2)	O1—Li1—O4^vii	152.74 (16)
O5^ii—Mn1—O4	177.06 (2)	O2^vi—Li1—O4^vii	108.68 (9)
O4^iii—Mn1—O4	103.37 (3)	O1—Li1—O5^viii	106.16 (10)
O1—P1—O2	119.93 (5)	O2^vi—Li1—O5^viii	118.72 (14)
O1—P1—O3^iii	110.17 (3)	O4^vii—Li1—O5^viii	83.24 (9)
O2—P1—O3^iii	106.43 (3)	O1—Li1—O8^i	76.84 (10)
O1—P1—O3	110.17 (3)	O2^vi—Li1—O8^i	80.21 (9)
O2—P1—O3	106.43 (3)	O4^vii—Li1—O8^i	86.20 (9)
O3^iii—P1—O3	102.18 (6)	O5^viii—Li1—O8^i	160.51 (11)
O5—P2—O4	119.30 (4)

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