Search results
Results From The WOW.Com Content Network
Elemental boron is found in small amounts in meteoroids, but chemically uncombined boron is not otherwise found naturally on Earth. Several allotropes exist: amorphous boron is a brown powder; crystalline boron is silvery to black, extremely hard (9.3 on the Mohs scale ), and a poor electrical conductor at room temperature (1.5 × 10 −6 Ω ...
Boron (5 B) naturally occurs as isotopes 10 B and 11 B, the latter of which makes up about 80% of natural boron. There are 13 radioisotopes that have been discovered, with mass numbers from 7 to 21, all with short half-lives, the longest being that of 8 B, with a half-life of only 771.9(9) ms and 12 B with a half-life of 20.20(2) ms.
Boron is found in nature on Earth almost entirely as various oxides of B(III), often associated with other elements. More than one hundred borate minerals contain boron in oxidation state +3. These minerals resemble silicates in some respect, although boron is often found not only in a tetrahedral coordination with oxygen, but also in a ...
Boron has found many industrial applications in recent decades, and new ones are still being found. A common application is in fiberglass. [47] There has been rapid expansion in the market for borosilicate glass; most notable among its special qualities is a much greater resistance to thermal expansion than regular glass.
Elemental boron has been found in star dust and meteorites, but does not exist in the high oxygen environment of Earth. It is difficult to extract from its compounds. The earliest methods involved reduction of boric oxide with metals such as magnesium or aluminium. However, the product is almost always contaminated with metal borides.
The boron was identified by the rover's laser-shooting Chemistry and Camera (ChemCam) instrument, which was developed at Los Alamos National Laboratory. [12] Hematite, clay minerals and boron are found to be more abundant in layers farther uphill in Gale Crater, compared with lower, older layers. [13]
Boron can also be created directly. The beryllium and boron are brought down to the ground by rain. [1] See Cosmogenic nuclide for a list of nuclides produced by cosmic ray spallation. The x-process in cosmic rays is the primary means of nucleosynthesis for the five stable isotopes of lithium, beryllium, and boron. [2]
Boron forms covalent bonds with other nonmetals and has oxidation states of 1, 2, 3 and 4. [19] [20] [21] Boron does not occur naturally as a free element, but in compounds such as borates. The most common sources of boron are tourmaline, borax, Na 2 B 4 O 5 (OH) 4 ·8H 2 O, and kernite, Na 2 B 4 O 5 (OH) 4 ·2H 2 O. [17] it is difficult to