Bismuth: Inorganic Chemistry

Abstract This review presents findings from 420 references. Bismuth has a diverse chemistry from the properties of the element to those of its important solid‐state compounds and its varied coordination complexes. Bismuth is the heaviest stable element whose chemistry is dominated by the +3 oxidation state, but −3, +1, +2, and +5 oxidation numbers are also accessible. In contrast to the lighter pnictogens, very few inorganic bismuth(V) compounds have been reported. The best characterized of these is BiF 5 , which is a strongly oxidizing Lewis acid that readily forms the BiF 6 − ion in the presence of a variety of F− ion donors. In this review, the chemistry of bismuth is organized by compound classification. Included are sections on the properties of the element, its intermetallic compounds and important solid‐state materials such as the bismuth oxides, chalcogenides, and pnictides. Recent work has been directed toward production of elemental bismuth and key solid‐state compounds in nanoparticle form. The solid‐state materials have important applications including high TC superconductors, ferroelectric, and piezoelectric materials, oxide ion conductors, catalysts, thermoelectric materials, etc. In its reduced compounds with alkali and alkaline earth metals, bismuth forms a number of homometallic and heterometallic anionic Zintl ions showing Bi–Bi bonding and a strong tendency toward cluster formation. Cationic clusters in reduced halide species have been observed. Bi–Bi single and double bonds are known. Molecular compounds are discussed and organized by the donor elements coordinated to bismuth, including sections on amines and amides, alkoxides, carboxylates, thiolates, and halides. The halides along with Bi(NO 3 ) 3 · 5H2O are amongst the most common starting materials for synthesizing other bismuth complexes. The alkoxide and carboxylate complexes are subject to facile hydrolysis leading to a wide variety of oxo‐alkoxide and oxo‐carboxylate complexes. Particularly stable configurations for these oxo clusters are Bi 9 and Bi 38 . These latter two cluster sizes stabilized by salicylate ligands are good model compounds for the bismuth subcarboxylate compounds, which have found widespread medicinal usage. High coordination numbers ranging from two to nine are common and the Bi 3+ ion is well‐known for its high Lewis acidity. Despite its identity as a heavy metal, its compounds are generally nontoxic to humans and enjoy a wide application as antibacterial and antifungal agents. Aspects of the biological chemistry of bismuth compounds are surveyed. A rich chemistry of bismuth coordinated to organometallic transition metal fragments is well developed. Many Fe, Co, Ru, Os, and Re metal carbonyl complexes have been reported as well as cyclopentadienyl metal derivatives. Unusual structure and bonding patterns have been observed in these compounds that include representatives from Groups 6 through 11 as well as one organometallic lanthanide complex.