Abstract
The properties, structure, and methods of preparation of the tetrahydroborates of beryllium, aluminium, and certain heavy metals (zirconium, hafnium, thorium, and uranium) are reviewed.
These compounds, which can provisionally be grouped together as the so-called covalent complex hydroborates, have much in common both as regards physical properties and high reactivity and as regards the nature of the chemical bond and the character of the chemical changes in which the M(BH4)n molecules participate. The main types of chemical reactions of the covalent tetrahydroborates, the structural principles lying at the basis of their molecular and crystal structures, and also the possibility of using covalent tetrahydroborates in various fields of inorganic synthesis are examined. 114 references.