Zwei neue Tetraphosphor-trichalkogeno-diiodide α′-P4Se3I2 und α′-P4S3I2 / Two New Tetraphosphorus-trichalcogeno-diiodies α′-P4Se3I2 and α′-P4S3I2

Abstract

Abstract α′-P4Se3I2 and α′-P4S3I2 were prepared by the reaction of P4S3 (P4Se3) with I2 in the molten state. The structure of α′-P4Se3I2 was determined. The compound crystallizes in the tetragonal space group I4̄2d with a - 1200.5(2) pm, c = 1518.8(4) pm, and eight molecules per unit cell. The structure was refined with 814 of 1402 observed reflections to a conventional residual of R = 0.045. One half of a molecule is forming the asymmetric unit. α′-P4S3l2 is isotypic with the lattice parameters a = 1182.2(2) pm and c = 1496.8(4) pm. 31P NMR data confirm that both modifica­tions have the same bicyclic molecular structure in solution as in the solid state and form an AA′BB′ system. Evidence is presented that the α-isomer is stabilized by the formation of two additional weak P-X bonds in this molecule.