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Calcium borate (Ca 3 (BO 3) 2). It can be prepared by reacting calcium metal with boric acid. The resulting precipitate is calcium borate. A hydrated form occurs naturally as the minerals colemanite, nobleite and priceite. [citation needed] One of its uses is as a binder in some grades of hexagonal boron nitride for hot pressing.
The tables below provides information on the variation of solubility of different substances (mostly inorganic compounds) in water with temperature, at one atmosphere pressure. Units of solubility are given in grams of substance per 100 millilitres of water (g/100 ml), unless shown otherwise.
The following chart shows the solubility of various ionic compounds in water at 1 atm pressure and room temperature (approx. 25 °C, 298.15 K). "Soluble" means the ionic compound doesn't precipitate, while "slightly soluble" and "insoluble" mean that a solid will precipitate; "slightly soluble" compounds like calcium sulfate may require heat to precipitate.
Common borate salts include sodium metaborate (NaBO 2) and borax. Borax is soluble in water, so mineral deposits only occur in places with very low rainfall. Extensive deposits were found in Death Valley and shipped with twenty-mule teams from 1883 to 1889. In 1925, deposits were found at Boron, California on the edge of the Mojave Desert.
Grade HBN contains a boron oxide binder; it is usable up to 550–850 °C in oxidizing atmosphere and up to 1600 °C in vacuum, but due to the boron oxide content is sensitive to water. Grade HBR uses a calcium borate binder and is usable at 1600 °C. Grades HBC and HBT contain no binder and can be used up to 3000 °C.
The isolated borate polyanion [B 5 O 6 (OH) 6] 3− has five boron atoms, therefore placing ulexite in the pentaborate group. Ulexite is a structurally complex mineral, with a basic structure containing chains of sodium, water and hydroxide octahedra. The chains are linked together by calcium, water, hydroxide and oxygen polyhedra and massive ...
The Borate Minerals are minerals which contain a borate anion group. The borate (BO 3) units may be polymerised similar to the SiO 4 unit of the silicate mineral class. This results in B 2 O 5, B 3 O 6, B 2 O 4 anions as well as more complex structures which include hydroxide or halogen anions. [2] The [B(O,OH) 4] − anion exists as well.
Despite the low reactivity of the tetrafluoroborate anion in general, BF − 4 serves as a fluorine source to deliver an equivalent of fluoride. [2] The Balz–Schiemann reaction for the synthesis of aryl fluorides is the best known example of such a reaction. [3]