Silicon: Inorganic Chemistry

Abstract

Silicon is an element of vital importance in many areas of modern synthetic chemistry, the electronics industry and in materials science. This article attempts to summarize the many types of important inorganic derivatives of silicon but excludes the chemistry of silicates and zeolites, which are covered in separate articles. The isolation of elemental silicon from sand is described together with the various methods of purification of the element for use in the semiconductor industry. A brief description of the occurrence of silicon in biology is also given. The bulk of the article deals with compounds of silicon organized according to coordination number. One‐coordinate compounds are short‐lived intermediates and are described briefly. Two‐coordinate compounds, silylenes, have become increasingly important in recent years as are transition metal complexes in which they act as ligands. The use of bulky substituents has allowed stable silylenes to be isolated and their chemistry is described. Three‐coordinate compounds comprise radicals, cations, anions, and silanes (compounds containing a double bond to Si). These species are also generally short‐lived and reactive. The bulk of the article deals with four‐coordinate compounds and is organized according to the substituents at silicon. The industrially important hydrosilanes and halosilanes are described together with the mixed halohydrosilanes and the less common pseudohalosilanes. Alkoxysilanes are also industrially important and these are discussed with other oxygen derivatives such as esters and silanols. Compounds containing SiN bonds are also common and have interesting structural features. The preparation and structures of transition metal complexes containing silyl ligands is described. This is followed by a description of compounds containing silicon with coordination number five or six. The final section describes the analytical methods for the determination of the composition and structure of inorganic silicon compounds. Compounds containing SiC bonds are excluded throughout.