Neutron-diffraction study of a structural phase transition in the deuterated molecular ferromagnet Fe(dtc) 2 Cl

The nuclear structure of Fe(dtc)2Cl, where dtc = diethyl-dithiocarbamate, is determined at several temperatures between 50 K and room temperature by high resolution powder neutron diffraction in a deuterated sample. Thermodiffractograms reveal that a structural transition extends over the temperature region from 300 to 75 K. In this structural transition one of the ethyl groups of Fe(dtc)2Cl, which at room temperature is disordered between two non-equivalent positions, becomes frozen in only one position in the low-temperature phase.