The Crystal Structure of Tetramethyltetraselenafulvalenium Perrhenate, (TMTSF)(ReO4)(C2H3Cl3)0.25

Abstract

Abstract The crystal structure of (TMTSF)(ReO4)(C2H3Cl3)2.25 was determined. The crystals are monoclinic P2/c, a=18.573(3), b=7.418(2), c=26.210(6)Å, β=107.85(2)°, Z=8. TMTSF molecules are stacked to form diadic columns along the b axis. The mode of intermolecular overlapping between adjacent TMTSF molecules shows a new mode of overlapping. The strong alternation of the intermolecular Se–Se distances along the TMTSF columns indicates that this compound is a Peierls insulator, which is consistent with the semiconducting behavior. The Peierls instability is accompanied by a bending distortion of the planar TMTSF molecules. The roomtemperature conductivity is 3×10−4 (Ω cm)−1, and the activation energy is 0.18eV. There are some short Se–O contacts between ReO4 anions and TMTSF stacks. The solvent molecnles (C2H3Cl3) are located in the channel formed along the b axis.