Boron nitride

Jime

May 4,2023
Updated 08:37 pm

Boron nitride is a thermally and chemically resistant refractory compound of boron and nitrogen with the chemical formula BN. It exists in various crystalline forms that are isoelectronic to a similarly structured carbon lattice. The hexagonal form corresponding to graphite is the most stable and soft among BN polymorphs and is used as a lubricant and an additive to cosmetic products. The cubic (zincblende aka sphalerite structure) variety analogous to diamond is called c-BN; it is softer than diamond, but its thermal and chemical stability is superior. The rare wurtzite BN modification is similar to lonsdaleite but slightly softer than the cubic form. Because of excellent thermal and chemical stability, boron nitride ceramics are used in high-temperature equipment and metal casting. Boron nitride has potential use in nanotechnology. Boron nitride exists in multiple forms that differ in the arrangement of the boron and nitrogen atoms, giving rise to varying bulk properties of the material. The amorphous form of boron nitride (a-BN) is non-crystalline, lacking any long-distance regularity in the arrangement of its atoms. It is analogous to amorphous carbon. All other forms of boron nitride are crystalline. The most stable crystalline form is the hexagonal, called h-BN, α-BN, g-BN, and graphitic boron nitride. Hexagonal boron nitride (point group = D6h; space group = P63/MMC) has a layered structure similar to graphite.

Boron and nitrogen atoms are bound by strong covalent bonds within each layer, whereas weak van der Waals forces hold the layers together. However, the interlayer "registry" of these sheets differs from the pattern seen for graphite because the atoms are eclipsed, with boron atoms lying over and above nitrogen atoms. This registry reflects the B–N bonds' local polarity and interlayer N-donor/B-acceptor characteristics. Likewise, many metastable forms consisting of differently stacked polytypes exist. Therefore, h-BN and graphite are very close neighbors, and the material can accommodate carbon as a substituent element to form BNCs. BC6N hybrids have been synthesized, where carbon substitutes for some B and N atoms. If you are looking for high quality, high purity, and cost-effective Boron nitride, or if you require the latest price of Boron nitride, please feel free to email contact mis-asia.

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