title: Synthesis, IR, UV-vis spectra, x-ray diffraction and band structure of a non-centrosymmetric borate single-crystal CaBiGaB(2)O(7).
abstract: A non-centrosymmetric borate, CaBiGaB(2)O(7), has been grown by a solid-state reaction method at a temperature below 700 °C. The single-crystal x-ray structural analysis has shown that it crystallizes in the tetragonal space group [Formula: see text] with a = 0.7457(1) nm, c = 0.4834(1) nm, Z = 2. It has a three-dimensional (3D) structure in which [B(2)O(7)](8-) groups are bridged by [GaO(4)](5-) tetrahedra through shared O atoms to form 2D [Formula: see text] layers that are further linked by Bi(3+)/Ca(2+) cations giving rise to the final 3D framework. The IR spectrum confirms the presence of [BO(4)](5-) groups and the UV-vis diffuse reflectance spectrum shows that the optical band gap is about 2.9 eV. This value is compared with our band structure calculations using the full potential linearized augmented plane wave approach within the framework of the Engel-Vosko GGA formalism.
authors.affiliation: Institute of Physical Biology, South Bohemia University, Nove Hrady 37333, Czech Republic. Institute of System Biology and Ecology, Academy of Sciences, Nove Hrady 37333, Czech Republic.
authors.forename: Ali Hussain
authors.initials: AH
authors.lastname: Reshak
authors.forename: Xuean
authors.initials: X
authors.lastname: Chen
authors.forename: Fangping
authors.initials: F
authors.lastname: Song
authors.forename: I V
authors.initials: IV
authors.lastname: Kityk
authors.forename: S
authors.initials: S
authors.lastname: Auluck