The molecular and crystal structure of thallium (I) methoxide

Abstract

An X-ray single-crystal structural study of thallium (I) methoxide, TlOCH 3, has yielded the thallium arrangement along with a proposed over-all configuration of the molecule. Thallium (I) methoxide is orthorhombic with a = 13·80 A ̊ , b = 6·98 A ̊ , and c = 13·66 A ̊ . The probable space grou[ is Pca2 1; the unit cell contains sixteen TlOCH 3 species. Two-dimensional Patterson and Fourier projections and least squares analyses gave the atomic positions of the heavy thallium atoms; the X-ray data were not sufficient to allow detection of the methoxide positions. Crystalline thallium (I) methoxide consists of tetrameric molecules in which the thallium atoms are at the corners of a regular tetrahedron. In this structure the average TlTl distance is 3·84 Å. A structure is proposed for (TlOCH 3) 4 in which thallium and methoxide groups each occupy the corners of two interpenetrating concentric tetrahedra of different size resulting in a distorted cube such that the TlOTl angle is > 90° and the OTlO angle is < 90°.