STRUCTURE OF ETHYLTRIPHENYLPHOSPHONIUM TRIIODIDE, [P(C2H5)(C6H5)3]I3

The title compound was obtained unexpectedly from a mixture of KReO4, triphenylphosphine and excess HI in ethanol. The crystal contains the tetrahedral [P(C2H5)(C6H5)3]+ cation in which the P-C distances range from 1.789 (13) to 1.819 (14) angstrom and the C-P-C angles from 108.3 (6) to 110.5 (6)degrees. The I3-counterion is roughly linear [I-I-I = 176.89 (5)degrees] and the I-I distances are 2.908 (1) and 2.948 (1) angstrom. Slightly puckered chains of I3- ions with interionic I...I contacts of 4.007 (1) angstrom form infinite layers separated by layers of phosphonium cations in the unit cell.