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The boron group is notable for trends in the electron configuration, as shown above, and in some of its elements' characteristics. Boron differs from the other group members in its hardness, refractivity and reluctance to participate in metallic bonding. An example of a trend in reactivity is boron's tendency to form reactive compounds with ...
Boron is added to boron steels at the level of a few parts per million to increase hardenability. Higher percentages are added to steels used in the nuclear industry due to boron's neutron absorption ability. [citation needed] Boron can also increase the surface hardness of steels and alloys through boriding.
Amorphous powder boron and polycrystalline β-rhombohedral boron are the most common forms. The latter allotrope is a very hard [ n 1 ] grey material, about ten percent lighter than aluminium and with a melting point (2080 °C) several hundred degrees higher than that of steel.
Tourmaline (/ ˈ t ʊər m ə l ɪ n,-ˌ l iː n / TOOR-mə-lin, -leen) is a crystalline silicate mineral group in which boron is compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium.
A boride is a compound between boron and a less electronegative element, for example silicon boride (SiB 3 and SiB 6). The borides are a very large group of compounds that are generally high melting and are covalent more than ionic in nature. Some borides exhibit very useful physical properties.
However, in group XIII (boron family), the electronegativity first decreases from boron to aluminium and then increases down the group. It is due to the fact that the atomic size increases as we move down the group, but at the same time the effective nuclear charge increases due to poor shielding of the inner d and f electrons.
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.
The boron framework of YB 41 Si 1.2 can be described as a layered structure where two boron networks (figures 9a,b) stack along the z-axis. One boron network consists of 3 icosahedra I1, I2 and I3 and is located in the z = 0 plane; another network consists of the icosahedron I5 and the B 12 Si 3 polyhedron and lies at z = 0.5.