Characteristics of boron

Boron is similar to carbon's capability to form stable covalently bonded molecular networks. Even nominally disordered (amorphous) boron contains regular boron icosahedra, which are connected randomly without long-range order. Crystalline boron is a rigid, black material with a melting point above 2000 °C. It forms four major allotropes: α-rhombohedral and β-rhombohedral (α-R and β-R), γ-orthorhombic (γ) and β-tetragonal (β-T). All four phases are stable at ambient conditions, and β-rhombohedral is the most common and regular. An α-tetragonal phase also exists (α-T) but is very difficult to produce without significant contamination. Most phases are based on B12 icosahedra, but the γ phase can be described as a rocksalt-type arrangement of the icosahedra and B2 atomic pairs. It can be produced by compressing other boron phases to 12–20 GPa and heating to 1500–1800 °C; it remains stable after releasing the temperature and pressure. The β-T phase is produced at similar pressures but at higher temperatures of 1800–2200 °C. The α-T and β-T phases might coexist at ambient conditions, with the β-T phase being the more stable. Compressing boron above 160 GPa produces a boron phase with an unknown structure. This phase is a superconductor at temperatures below 6–12 K. Borospherene (fullerene-like B40 molecules) and borophene (proposed graphene-like structure) were described in 2014. If you are looking for high quality, high purity, and cost-effective boron, or if you require the latest price, please email contact mis-asia.