On the Relative Stability of Donor and Acceptor Stacks Against the Peierls Distortion in the Tetrathia- and Tetraselenafulvalenium Tetracyanoquinodimethanide Family of Organic Metals

An organic conductor having a Peierls instability driven by donor stacks is considered. The compound is tetramethyltetraselenafulvalene-2,5-dimethyltetracyanoquinodimethane. Magnetic data confirm that the instability is donor driven. The influence of the unit cell size is examined. The unit cell size can be changed by the substitution of sulphur or selenium or by the introduction of methyl groups.

The consequences of this are discussed