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The borate ion is BO33-. A borate is a compound of the borate ion with metallic elements. Boron found in nature is commonly as a borate mineral. Boron is also found combined with silicate to form complex borosilicate minerals such as the tourmalines.
Borate exists in many forms. In acid conditions, as boric acid, H3BO3. In more basic conditions, it occurs as the dihydrogen borate ion, H2BO3-; the hydrogen borate ion, HBO32-; and finally borate ion, BO33-.
Borate can form many polymeric ions. Especially common is the tetraborate ion, B4O72-; also as the hydrogen tetraborate ion, HB4O7-. It also occurs as triborate and pentaborate. The various metaborate ions have an empirical formula of BO2-, and form metaborate compounds. For the borate compounds, formation of complicated infinite anion structures is extensive, perhaps surpassed only by the silicates.
Common borate salts include sodium metaborate, NaBO2, and sodium tetraborate, Na2B4O7. The latter also occurs naturally as the hydrous mineral borax, Na2B4O7ยท10H2O. Death Valley, California is noted for borate mining. The Atacama Desert in Chile also contains mineable borate concentrations.
Various forms of borate are used as wood preservatives.
Borate esters include trimethyl borate, B(OCH3)3, which is used as a precursor to boronic esters for Suzuki couplings.
External links
TriMethyl Borate as a precursor to boronic esters
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