Iso-structural phase transition in tetramethylammonium nickel(II) nitrite [(CH3)4N][Ni(NO2)3

Abstract

Abstract The title compound, tetramethylammonium nickel nitrite [(CH3)4N][Ni(NO2)3], has a hexagonal perovskite-type structure with formula ABX3. It undergoes two reversible phase transitions occurring at about 409.1 and 428.4 K, associated with dielectric transitions. DSC measurement and dielectric measurement confirm the transition. The variable-temperature X-ray structural determinations and the powder X-ray diffraction (PXRD) experiments reveal that this compound has the same space group P 3 ¯ m 1 (No. 164) at 293 K, 413 K and 438 K. The phase transitions are caused by the rotation of the [(CH3)4N]+ cation.