Synthesis and crystal structure of the low-temperature modification of lithium potassium zinc diphosphate LiKZnP2O7

A new polymorphic modification, α-LiKZnP₂O₇, has been synthesized, which is a low-temperature modification of the LiKZnP₂O₇ compound. The crystal structure is determined by the Rietveld method from the X-ray powder diffraction data. The compound crystallizes in the monoclinic system (space group Pc, a = 12.3621(3) Å, b = 5.0655(1) Å, c = 10.2365(3) Å, β = 90.88(1)°, Z = 2) and has a framework structure similar to that of the high-temperature β phase. The framework is formed by the diphosphate groups and the oxygen tetrahedra of the zinc and lithium atoms, which statistically uniformly occupy equivalent positions in the structure.