Neutron powder diffraction data for low- and high-temperature NASICON phases of LiM2(PO4)3 (M=Hf, Sn)

The new diffraction patterns of the low- and high-temperature phases of Li0.87Hf2.032 (PO4)3 and LiSn2(PO4)3 are given and indexed on the basis of a structure refinement from neutron powder data using Rietveld method. The two isotypic compounds present a reversible phase transition: triclinic (LT, space group P1) <=> rhombohedral (HT, space group R3c) which proceeds by topotactic distortion of the structural skeleton. © 1999 International Centre for Diffraction Data. [80885-7156(98)00702-7]