Polymeric spin transition compounds : EXAFS and thermal behavior

Michalowicz, A. [] Moscovici, J. [] Garcia, Yann [University of Mainz (Germany)] Kahn, O. []

The structures of large thermal hysteresis Fe(II) polymeric spin transition compounds have been studied by EXAFS. The asumption that a peak at 7 A can be assigned to a multiple scattering double metal-metal distance in an aligned polymeric structure is con_fumed. For the first time, such an aligned structure was observed on High Spin (HS) compound of the family. A qualitative study of the thermal variation of this multiple scattering peak was performed. The correlation between this thermal behaviour, due to variations in the vibrational entropy, and the electronic structure of the metallic ions is discussed.