We report the first ab initio computational study of the structural and ele
ctronic properties of BEDT-TTF charge transfer salts, which have wide rangi
ng physical properties which are derived primarily from the packing of the
donor-radical cations. The calculations accurately reproduce the observed c
rystal structure of the material and provide new information on the electro
nic structure of the (BEDT-TTF)[FeBr4] salt.