Borataanion

Borataanion, commonly referred to as the borate ion, is the class of anions derived from boric acid (H3BO3) by deprotonation and/or condensation of boron-oxygen units. In aqueous solution, the most prevalent species is the tetrahydroxyborate ion, B(OH)4−, formed when boric acid reacts with hydroxide: B(OH)3 + 2 H2O ⇌ B(OH)4− + H3O+. This monoanion dominates in neutral to mildly basic solutions and represents the main borate form under many laboratory conditions.

In more concentrated or strongly basic environments, borate units can condense into polyborate anions. The exact species formed depend on pH, concentration, and counterions; common examples include larger borate clusters such as tetraborate and other polyborate ions. The borate system is therefore highly pH-dependent, with B(OH)4− prevailing at moderate pH and more polymerized borates appearing at higher pH or boron concentration.

Preparation and occurrence: Borate species arise from boron-containing materials such as boric acid or borates used commercially. For example, borax (sodium tetraborate decahydrate) dissolves to produce borate species in solution, including B4O7^2−–type units, depending on conditions. The speciation of boron-oxygen anions reflects hydration, condensation, and the presence of counterions.

Applications and relevance: Borate buffers provide stability around pH 9–10 and are widely used in biochemistry and molecular biology. Borate salts serve as fluxes in glass and ceramic industries, as corrosion inhibitors, and in some agricultural formulations as micronutrient sources. The borate framework is also relevant in materials science for polyborate glasses and related compounds.

Note: The term boratanion is largely synonymous with borate ion; specific names such as orthoborate or tetraborate describe particular structural motifs.