New organic conductors (BEDO-TTF)(m)MHg(SCN)(4)

A series of new BEDO-TTF salts with the [Hg(SCN)(4)](2-) anion and Li+, K+, NH4+, Rb+, and Cs+ cations has been prepared. The salts with Li, K, NH4, a nd Rb show metallic behaviour down to 4 K, the Cs salt behaves as a metal d own to 85 K, at lower temperatures a gradual increase of resistance takes p lace. Crystals of (BEDO-TTF)(5)[CsHg(SCN)(4)](2) are triclinic: a=10.436(2) , b=10.709(2), c = 19.973(4) Angstrom, alpha= 89.59(2), beta= 81.88(2), gam ma= 72.76(2)degrees, P (1) over bar, Z= 1. The structure of this salt appea rs as the alternation of BEDO-TTF donor layers of the 'I-3' type and inorga nic layers composed of infinite anion chains incorporating Csf cations. (C) 1999 Published by Elsevier Science S.A. All rights reserved.