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Boron phase α-R β-R γ β-T Symmetry ... Boron is not generated in the normal course of stellar nucleosynthesis and is destroyed in stellar interiors. [72]
γ-boron: Comparison of X-ray diffraction data of Wentorf [43] (bottom) with the modern data [11] The γ-phase can be described as a NaCl-type arrangement of two types of clusters, B 12 icosahedra and B 2 pairs. It can be produced by compressing other boron phases to 12–20 GPa and heating to 1500–1800 °C, and remains stable at ambient ...
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.
Borophene is a crystalline atomic monolayer of boron, i.e., it is a two-dimensional allotrope of boron and also known as boron sheet. First predicted by theory in the mid-1990s, [1] different borophene structures were experimentally confirmed in 2015. [2] [3]
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.
As previously discussed, a nitrogen lone pair donates into an empty boron p-orbital to form a π bond; the out of phase combination serves as a high-energy LUMO+2. [19] Diborene B-B σ-bonding-derived NBO. [18] Braunschweig's 2018 dinitrogen activation with a transient borylene species Diborene B lone pair-derived NBO. [18]
Main isotopes of boron; Main isotopes Decay; abundance half-life ... Phase at STP: Oxidation states ... normal-code dm1−4 en-name en-link
Unlike silicates, boron minerals never contain boron with coordination number greater than four. A typical motif is exemplified by the tetraborate anions of the common mineral borax , shown at left. The formal negative charge of the tetrahedral borate center is balanced by metal cations in the minerals, such as the sodium (Na + ) in borax . [ 1 ]