For pt.VI see ibid., vol.14, p.5247 (1981). The crystal structure of cadmium sulphur boracite at room temperature has been determined with X-ray diffraction measurements from a single-crystal sample. Within a B₇O₁₂ framework, very like that found in the 'standard' cubic structure of the metal-halogen boracites, the Cd ions are disordered over two sites each approximately 0.5 AA from the standard metal site; and the S site-at the position occupied by Cl, Br or I in the halogen boracites-is surrounded by four peaks of electron density in a regular tetrahedral array. The evidence strongly suggests that this distribution can be interpreted as a disordered S₂ ion. The distance between each 'outer', partially-occupied S site and its nearest Cd (disordered) sites is too small for a Cd-S approach. Hence there must be some mutual short range ordering of the Cd and S₂ distributions, and it would seem probable that there is a fully ordered phase at a lower temperature. There is no apparent simple geometrical requirement for the Cd ion to occupy displaced sites: it is suggested that this feature reflects an affinity of the Cd²⁺ ion for sulphur coordination.