Crystal Growth, Room Temperature Crystal Structure and Phase Transitions of KMnPO4

Abstract

Single crystals of KMnPO4 grown in a KCl flux show ferroelastic domains. The structure was determined on an optically controlled single domain crystal by X-ray diffraction methods. The cell is triclinic with dimensions a = 5.4813(5), b = 8.627(1), c = 8.887(1), in Å, α = 87.73(1)°, β = 89.10(1)°, γ = 88.01(1)°, Vᴍ = 419.6(1) Å3 and Z = 4. The structure is closely related to the stuffed β-tridymite type. DTA experiments between room temperature and 1000 °C and polarized light microscopy observations showed four phase transitions: at 165, 330, 353 and 707 °C.