IR and Raman spectroscopy, normal coordinate analysis, and molecular mechanics were used to study the conformations of the Cl2P-O-(CH2)(2)SCN molecule. It is shown that in the low temperature crystals the molecule exists in two or more conformations, and in the liquid in at least three conformations. In both liquid and solid phases there exist the conformers with the O ... S and/or P ... S intramolecular distances comparable with the sums of the corresponding van der Waals radii. The substantial energy preference of the gauche conformation about the CC bond in the liquid state is assigned to certain attractive intramolecular interactions between the sulfur and phosphorus (or oxygen) atoms. The energy of the interaction may amount to about 2-4 kcal mol(-1). (C) 1997 Elsevier Science B.V.