Chemistry, basics nonmetal compounds

Most nonmetal borates reported in the literature are ammonium and substituted ammonium salts, hi general, boric acid forms salts with alkyl- or aryl-amines that are roughly as or more basic than pyridine. Depending on the reaction conditions, a number of different crystalline borates might be isolated from a given amine. However, the chemistry of substituted amine borates is dominated by the occurrence of pentaborates, and relatively few compounds in this class have been reported containing more basic borates anions. 

The Group lllA elements clearly show the trend of increasing metallic character in going down any column of elements in the periodic table. Boron, at the top of Group lllA, is a metalloid, and its chemistry is typical of a nonmetal. The compound B(OH)3 is actually acidic (boric acid). The rest of the elements (aluminum, gallium, indium, and thallium) are metals, but their hydroxides change from amphoteric (acidic and basic) for aluminum and gallium to basic for indium and thallium. 

Metal oxides belong to a class of widely used catalysts. They exhibit acidic or basic properties, which make them appropriate systems to be used as supports for highly dispersed metal catalysts or as precursors of a metal phase or sulfide, chloride, etc. Simple metal oxides range from essentially ionic compounds with the electropositive elements to covalent compounds with the nonmetals. However, taking into account the large variety of metal oxides, the principal objective of this book is to examine only metal oxides that are more attractive from the catalytic point of view, and most specifically transition metal oxides (TMO). In particular, TMO usually exhibit nonstoichiometry as a consequence of the presence of defective structures. The interaction of TMO with surfaces of the appropriate carriers develop monolayer structures of these oxides. The crystal and electronic structure, stoichiometry and composition, redox properties, acid-base character and cation valence sates are major ingredients of the chemistry investigated in the first part of the book. New approaches to the preparation of ordered TMO with extended structure of texturally well defined systems are also included. 

---