This article discusses the major classes of inorganic polymers, including borates and three classes of silicon polymers—silicates, silicones (silicone), and silanes (silane). For a more detailed discussion of borates and silicates, see mineral.

These compounds are salts of the oxyacids of boron (B), such as boric acid, H₃BO₃, metaboric acid, HBO₂, and tetraboric acid, H₂B₄O₇. Borates result either from the reaction of a base with a boron oxyacid or from the melting of boric acid or boron oxide, B₂O₃, with a molten metal oxide or hydroxide. Borate anion structures range from the simple trigonal planar BO₃³⁻ ion to rather complex structures containing chains and rings of three- and four-coordinated boron atoms. (See chemical bonding for a description of molecular shapes.) For example, calcium metaborate, CaB₂O₄, consists of infinite chains of B₂O₄²⁻ units, whereas potassium borate, K【B₅O₆(OH)₄】 · 2H₂O (commonly written as KB₅O₈ · 4H₂O), consists of two B₃O₃ rings linked through a common four-coordinated boron atom. The tetraborates, B₄O₅(OH)₄²⁻, contain both three- and four-coordinated boron surrounded trigonally and tetrahedrally, respectively, by oxygen (O) atoms. Commercially, the most important borate is borax, or sodium tetraborate decahydrate, Na₂B₄O₇ · 10H₂O. Borax is found naturally in dry lake beds, such as Searles Lake in California. It can be used to soften water and to make washing compounds. Its usefulness arises from the insolubility of calcium and magnesium borates and the alkaline or basic nature of aqueous solutions of borax. Borax is also used in the manufacture of borosilicate glass and enamels (enamel) and as a fire retardant.

Silicones (silicone) are polymeric organosilicon compounds containing Si−O−Si linkages and Si−C bonds. They are generally very stable, because of the presence of strong silicon-oxygen and silicon-carbon bonds. A general formula for silicones is (R₂SiO)_x, where R can be any one of a variety of organic groups. Silicones may be linear, cyclic, or cross-linked polymers, as shown here.

Linear and cyclic silicones are produced by the reaction of water with organochlorosilanes of the general formula R₂SiCl₂, followed by a polymerization reaction that occurs by the elimination of a molecule of water from two hydroxyl groups of adjacent R₂Si(OH)₂ molecules.

Silicone polymers incorporate some of the properties of both carbon-hydrogen compounds and silicon-oxygen compounds. They are stable to many chemical reagents and to heat. Depending on their degree of polymerization and the complexity of the attached organic groups, silicones can occur in the form of oils, greases, rubberlike substances, or resins (resin). They are used as lubricants, hydraulic fluids, and electrical insulators. They are especially useful as lubricants in applications where there are extreme variations in temperature, because their viscosity changes very little as the temperature changes. Silicones are also water-repellent. Paper, wool, silk, and other fabrics can be coated with a water-repellent film by exposing them for a short time (one to two seconds) to the vapour of trimethylchlorosilane, (CH₃)₃SiCl. The −OH groups on the surface of the materials react with the silane, and the surface becomes coated with a thin water-repellent film of (CH₃)Si−O− groups.

Silanes (silane) are compounds of silicon and hydrogen. Silicon forms a series of hydrides (hydride) that have the general formula Si_nH_{2n + 2}, including SiH₄, Si₂H₆, Si₃H₈, and Si₄H₁₀. These compounds contain Si−H and Si−Si single bonds. Silicon possesses empty valence-shell d orbitals (see chemical bonding), which cause the chemistry of silanes to be quite different from that of the corresponding carbon-hydrogen compounds (hydrocarbons (hydrocarbon)). For example, silanes inflame spontaneously in air, whereas the corresponding hydrocarbons do not.

The simplest silane, SiH₄, is called silane. It has a formula and a tetrahedral structure analogous to the hydrocarbon methane, CH₄. It can be prepared in the laboratory by the addition of aqueous acid to an ionic silicide such as magnesium silicide, Mg₂Si.

Silanes react readily with hydrogen halides to produce halogenated silanes. For example, silane reacts in a stepwise manner with hydrogen bromide, HBr, to yield all possible combinations of brominated silane from SiH₃Br to SiBr₄. Silanes are also very reactive toward hydroxides (hydroxide), producing silicate ions and hydrogen gas.