Larger borates are composed of trigonal planar BO 3 or tetrahedral BO 4 structural units, joined together via shared oxygen atoms, and may be cyclic or linear in structure.īoron trioxide is one of the oxides of boron it is a white, glassy solid with the formula B 2O 3. The simplest borate anion, BO 3 3-, has a trigonal planar structure and is analogous to the carbonate anion CO 3 2-, which is isoelectronic. It is acidic because it reacts with OH − from water, forming − and releases the corresponding proton left by the water autoprotolysis.ī(OH) 3 + 2 H 2O ⇌ − + + (p K a = 8.98)Īll borates are considered derivatives of boric acid B(OH) 3. In water, it behaves as a Lewis acid, accepting the electron pair of a hydroxyl ion produced by the water autoprotolysis. Boric acid is a weak proton donor – it can accept an electron pair. When a trigonal boron atom accepts a pair of electrons from a Lewis base, it adopts a tetrahedral configuration, and the octet rule is satisfied.ī- Boric Acid is an inorganic acid. The incomplete octet means that Borates act as Lewis acids. – The ultra-hard crystal Boron Carbide Boric Acid ->Boratesīorates are the form in which boron most often occurs in nature, mainly as borate minerals and borosilicates. – Borate Salts, including the mineral Borax and Sodium Metaborate
– Boric acid – all Borates are derived from Boric Acid Boron Compounds – Boric Acid and Boratesīoron is the lightest element of the boron group (above), with three valence electrons that form covalent bonds to produce several compounds, including: The most common isotopes are B-10 (natural abundance 19.9 percent) and B-11 (natural abundance 80.1 percent). The number of isotopes – atoms of the same element with a different number of neutrons – is 6. Natural boron is composed of two stable isotopes, one of which ( boron-10) has several uses as a neutron-capturing agent. – Crystalline boron is silvery to black, extremely hard (about 9.5 on the Mohs scale), and a poor electrical conductor at room temperature. Several allotropes exist, including α-rhombohedral B, β-rhombohedral B, γ-B, tetragonal boron Its boiling point is 7,232 degrees F (4,000 degrees centigrade). The melting point of Boron is 3,767 degrees Fahrenheit (2,075 degrees Celsius). The Atomic weight (average mass of the atom) is 10.81 with a density of 2.37 grams per cubic centimeter. Classified as a metalloid, boron is a solid at room temperature. Boronīoron is a chemical element with symbol B and atomic number – number of protons in the nucleus – 5. The elements in the boron group all have three valence electrons (or triels). The Boron Groupīelonging to the Boron Group are the chemical elements in group 13 of the periodic table: boron, aluminum, gallium, indium, thallium, and some include nihonium. Industrially, the very pure element is produced with difficulty because of contamination by carbon or other elements that are reputed to resist removal. Boron is a metalloid found in small amounts in meteoroids, but chemically uncombined boron is not otherwise found naturally on Earth. Elemental BoronĮlemental Boron is a low-abundance element in the Solar System and in the Earth’s crust (about 0.001 percent by weight of Earth’s crust).
Still, rasorite is the most important source of boron, found in extensive deposits in California, USA, in and around the Mojave Desert. Extensive borax deposits are found in Turkey, which has the largest borax deposits. A Martian meteorite that landed in Antarctica contained significant traces of boron.īoron is an orthoboric acid in some but not all volcanic spring waters and borates in the minerals borax and colemanite. Boron has also landed on our planet from Mars. A June 2014 study found that boron is present in rocks that date back to 3.8 billion years ago. The element stabilizes ribose, part of RNA, the self-assembling molecule that may have preceded DNA.
Boron may have been the key to the evolution of life on Earth.
0 kommentar(er)
