Stereochemistry of some organic derivatives of Group Vb elements. Part VIII. Crystal and molecular structure of µ-chloro-bis[hydroxytriphenylarsenic](1+) dichloroiodate(1–)

Abstract

Crystals of the title compound are monoclinic, space group P2₁/c, with Z= 4 in a unit cell of dimensions: a= 14.259(2), b= 14.374(2), c= 17.653(3)Å. β= 90.15(1)°. The structure was solved by the heavy-atom method and refined by least-squares techniques to R= 0.046 for 2441 observed intensities. The compound is correctly formulated as [Ph₃As–O–H ⋯ Cl ⋯ H–O–AsPh₃]+ ICl₂^–. The chloride ion bridges the hydroxy groups via strong hydrogen bonds. The stereochemistry of the arsenic atoms is very slightly distorted tetrahedral. Mean dimensions are: As–C(Ph) 1.901 (10), As–O 1.727(7) and 1.716(7), I–Cl 2.513(3) and 2.542(4)Å. The hydrogen atoms involved in the bridging have been located, with mean distances O–H 0.89 and H ⋯ Cl^–2.13 Å.