Structural phase transitions in the cyano-elpasolite CS2NaCo(CN)6, a neutron diffraction study

Abstract We have studied the phase transformations in the cyano-elpasolite Cs 2 NaCo(CN) 6 by neutron powder diffraction in the temperature range 300–630 K. The temperature evolution of diffraction patterns clearly indicates two phase transitions at T 1 =500 K and T 2 =590 K. Detailed characterization of structural changes confirms the sequence of phase transitions proposed earlier (P2 1 /n↔P4/mnc↔Fm3 m) and provides, for the first time, a microscopic picture of the transformations of Cs 2 NaCo(CN) 6 .