Valence-Ordering Structures and Magnetic Behavior of Metallic MMX Chain Compounds

Abstract

Chains change: Novel valence-ordering structures of the ground states of MMX chain compounds, [Pt2(RCS2)4I]∞ (1: R=nBu, 2: R=Et), are determined by low-temperature crystal-structure analyses to be -Pt2+-Pt3+-I−-Pt3+-Pt2+-I−-. Magnetic susceptibility measurements of 1 (see graph) revealed an abrupt drop in magnitude from a 1D antiferromagnetic spin system to a spin-singlet state accompanying a first-order phase-transition around 210 K. This result is in contrast to the spin degree of freedom of 2 that survived down to 2 K.