borates

Borates are chemical compounds that contain boron and oxygen, often with hydrogen and other elements. In borates, boron is typically in the +3 oxidation state and forms coordination geometries such as BO3 triangles and BO4 tetrahedra. These units link to form a variety of anionic networks, and borates occur as minerals and as acids and salts. In aqueous solutions, borate species include B(OH)4− and related boron-oxygen complexes.

Natural occurrence and minerals: Borates are common in arid regions and evaporite deposits. Important ore minerals include borax (sodium borate decahydrate, Na2B4O7·10H2O), colemanite (Ca2B6O11·5H2O), kernite (Na2B4O7·5H2O), and ulexite (NaCaB5O9·8H2O). Other borates include boracite (Mg3B7O13Cl). These minerals form by the evaporation of boron-rich brines and are found in places such as Turkey, the United States (notably California and Nevada), Chile, and Argentina. Ulexite is known for its fibrous crystals and distinctive optical properties.

Production and uses: Borates are extracted by solution mining and processed to yield borax, boric acid, and various sodium, calcium, or magnesium borates. The main industrial uses are in glass and ceramics production, fiberglass and enamel manufacturing, and detergents. They also serve as micronutrients in agriculture, flame retardants, stabilizers and catalysts in polymers, and additives in cements and other materials.

Properties and safety: Many borates are white or colorless solids with properties that depend on hydration and crystal form; solubility varies among species. Handling and environmental considerations are important due to potential boron release into water systems. Proper storage and regulatory compliance are customary in mining and processing of borates.