A New Isomer of Diiodotetraphosphorus Trisulfide. the Preparation and Crystal Structure of ²-P4S3I21

Abstract

²-P4S3I2 is prepared by the reaction of P4S3 with I2 in solution. The structure was determined from three-dimensional X-ray data collected by standard Weissenberg multiple-film techniques and refined with a data set collected by counter methods using Mo radiation. The compound crystallizes in the orthorhombic space group Pnma with a = 9.399 (2) A, b = 16.343 (4) A, c = 6.657 (9) A, and four molecules per unit cell. The structure was refined with 259 observed reflections to a conventional residual of R = 0.037. The molecules lie on a crystallographic mirror plane, with one sulfur and two phosphorus atoms on the mirror. The P-S bond lengths range from 2.091 (16) to 2.145 (10) A, the P-P bond length is 2.221 (10) A, and the P-I bond length is 2.471 (8) A. Evidence is presented to support the reaction sequence P4S3 + I2 → ²-P4S3I2 → α-P4S3I2, where (α-P4S3I2 is a previously reported P4S3I2 structure which has a P-S framework different from that of ²-P4S3I2. © 1971, American Chemical Society. All rights reserved.