O 2s-band

The characteristic feature of this band structure is that the properties of the orbitals of the atoms and atomic groups are approximately preserved. The lowest band is primarily an O 2s-band. The next band is primarily an O 2p-band. These bands are fully occupied valence bands. The next band is primarily of t2 character the following band primarily of Og character. These bands are unoccupied and are called conduction bands. The Fermi level in the ideal crystal is between the highest occupied and the lowest unoccupied bands. The band gap of 3,2 eV makes Ti02 an insulator. 

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