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].

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)

Experimental
The synthesis of the polyphosphate Li 2 MnP 4 O 12 by wet process, was made starting from the stoechiometric proportions of (LiNO 3 99,9%) (I); (Mn(NO 3 ) 2 ,4H 2 O 99%) (II) and ((NH 4 ) 2 HPO 4 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 Li 2 MnP 4 O 12 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.

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.

Dilithium manganese(II) catena-tetrakis(polyphosphate)
Crystal data Refinement. Refinement of F 2 against all reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on all data will be even larger.