Tetraethyldistibine, Et4Sb2, a new antimony source for MOCVD is evaluated. It is shown to be a useful and safe dopant feedstock for low temperature growth of p-type Hg1-xCdxTe. Attempted purification of Et4Sb2 by adduct formation with CdI2 resulted in isolation of a polymeric chain adduct [Et4Sb2 · 2CdI2]n (1). The structure of 1 has been determined by X-ray crystallography and consists of chains of iodide-bridged Et4Sb2 · 2CdI2 units which have CdI2 bonded to each antimony atom. Antimony and two iodine atoms form a trigonal planar arrangement around cadmium, and two weak axial bonds to the iodine atoms of adjacent units give distorted trigonal bipyramidal coordination to cadmium. The distibine molecules display a skew configuration of the ethyl substituents. The SbII-SbII and SbII-CdII distances are 2.784(2) and 2.822(2) Å respectively. Dropwise addition of Me2Cd to Et4Sb2 in the absence of solvent gave an insoluble 1:1 adduct. Et4Sb2 reacts with Te but not with Cd or Hg.