Phase transition and decomposition of tetraethylammonium tetrahalomanganate in the solid state

Abstract

The synthesis, magnetic and electronic spectral studies of tetrahedral tetrahalometallates have drawn much attention since 1958 [1]. A lot of studies have been made with tetraalkyltetrahalometallates due to their temperature-dependent spectral, magnetic, thermal, etc., properties [2]. Tetramethylammoniumtetrahalometallates undergo high-temperature normal phase transition to the incommensurate phase on cooling. The incommensurate phase undergoes a transition to the commensurate phase on further cooling [2]. Low-temperature phase transitions of tetraethylammoniumtetrachlorometallates of first-row transition metals are known [3], but the phase transitions of the corresponding tetrabromo compounds and aboveambient temperature phase transitions of [Net₄]₂MX₄ are not yet reported. The present paper reports the phase transitions of [Net₄]₂MnX₄ (X = Cl or Br) starting from 233 K to their corresponding decomposition temperatures. It also includes their thermal decompositions.