Electronic Structure and Chemical Bond of Titanium Diboride

Titanium diboride was calculated by the density function and discrete variational (DFT-DVM) method to study the relation between structure and properties.Titanium and its first-nearest boron atoms form a strong covalent bond,so TiB2 has high melting point,hardness and chemical stability.Titanium atom releases two electrons to form Ti2+ ions,and a boron atom gets one electron to come into B- ion.B- takes the sp2 hybrid and forms σ bonds to link other boron atoms in the same layer.The other one 2pz orbital of every B- ion in the same layer interacts each other to form the π molecular orbital,so TiB2 has fine electrical property.The calculated density of state is close to the result of XPS experiment of TiB2.Mainly Ti3d and B2p atomic orbitals contribute the total DOS near the Fermi level.