X-Ray powder structure determination of Li6P6O18 center dot 3H(2)O

Preparation, characterization by X-ray diffraction, IR absorption, DTA-GTA analysis and ab-initio crystal structure determination sire reported for a new lithium cyclohexaphosphate hydrate Li6P6O18. 3H(2)O. It crystallizes in a trigonal (rhomboedral) cell (space group <R(3)over bar>m No 166, Z = 6) with a = 15.7442(2) Angstrom, c = 12.5486(2) Angstrom. X-ray powder diffrac tion pattern data was refined by Rietveld profile technique and lead to R-B ragg = 0.09. The crystal structure of Li6P6O18. 3H(2)O is built up from [P6 O18](6-) ring anions, having the 3m symmetry, alternating along the (3) ove r bar axis with rings made of six LiO4 tetrahedra and six LiO5 pseudo squar e pyramids sharing common edges.