Refinement of the crystal structure of zinckenite, Pb6Sb14S27*

Abstract
The crystal structure of zinckenite, Pb 6 Sb 14 S 27 , has been refined to an R value of 0.13 with the aid of three-dimensional x-ray data. The intensities were measured by means of a Supper-Pace autodiffractometer, using Cu Kα radiation. The hexagonal unit cell, with a = 22.148(6) and c = 4.333(6) Å, contains 1½ formula units. Results of refinements in the space groups P 6 3 / m and P 6 3 are compared according to H amilton's R -ratio test. The latter space group is the correct one.