Boron Carbide Secrets

Resumo

The issues of the composition-structure relationship of boron carbide are discussed. A new hypothesis based on the presence of channels with a diameter of 2.7–2.9 Å in crystals, into which C or B atoms can be intruded, has been proposed. The intrusion has been confirmed by the data of quantum-chemical simulation using VASP program. It has been shown that the introduction of atoms into the channels changes the cell parameters and deforms the structural fragments. The latter may cause the formation of monoclinic crystals of boron carbide. According to the quantum chemical simulattions, the cell parameters of boron carbide crystals of the same composition depend on the site of intrusion of the C atoms into the channels.