First-order phase transition in the organic metal κ-(BETS)2C(CN)3

Evidence concerning the occurrence of a first-order phase transition around 260 K in the organic metal κ-(BETS)2C(CN)3 is reported and the effect of the transition on the crystal and electronic structure of the salt is discussed. Determination of the crystal structure at 50 K has shown that the main structural change brought about by the transition affects the anion sublattice. Although there are noticeable changes in the chalcogen⋯chalcogen short contacts of the donor lattice it is shown that the Fermi surface is left unaltered by both the first-order transition and the thermal contraction down to 50 K.