Electronic Structures and Chemical Bonding of the Layered Tungsten Borides: an ab initio Calculation

摘要

We have investigated the electronic structures and chemical bonding of four tungsten borides,including two WB2 compounds with different crystal structures,α-W2B5 and ε-WB2.5,by ab initio calculations based on density function theory (DFT).The calculated density of state (DOS) shows that all compounds are metallic.The DOS at Fermi level is mainly contributed from 5d states of W atoms.The strong covalent bonds of boron atoms make these compounds stable.Due to a lack of electrons in boron sublattices,weak ionic bonds are generated.The charge density distributions indicate the solid B layers or B polyhedrons are interleaved by the W layers.