![]() – 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. Pyykkö, personal communication, 1998, 204, 2008, 2010.Boron may have been the key to the evolution of life on Earth. Lide, (ed.), CRC Handbook of Chemistry and Physics 1999-2000 : A Ready-Reference Book of Chemical and Physical Data (CRC Handbook of Chemistry and Physics, CRC Press, Boca Raton, Florida, USA, 79th edition, 1998. ![]() I am grateful to Professor Pekka Pyykkö (University of Helsinki, Finland) who provided the nuclear quadrupole moment data in this and the following two references. Where given, data for certain radioactive nuclei are from this reference. Mason in Multinuclear NMR, Plenum Press, New York, USA, 1987. I am grateful to Professor Robin Harris (University of Durham, UK) who provided much of the NMR data, which are copyright 1996 IUPAC, adapted from his contribution contained within this reference. 5, John Wiley & Sons, Chichester, UK, 1996. Harris in Encyclopedia of Nuclear Magnetic Resonance, D.M. Magnetogyric ratio, γ (10 7 rad T ‑1 s -1) ![]() Table of NMR-active nucleus propeties of boron Ĭommon reference compound: BF 3.OEt 2/CDCl 3. Kuchitsu in Quantities, Units and Symbols in Physical Chemistry, Blackwell Scientific Publications, Oxford, UK, 1988.
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