X-ray diffraction, X-ray photoelectron spectra, crystal structure, and optical properties of centrosymmetric strontium borate Sr2B16O26.
We report results of X-ray diffraction (XRD) and valence band X- ray photoelectron (VB-XPS) spectra for strontium borate Sr(2)B(16)O(26). The X-ray structural analysis shows that the single crystals of Sr(2)B(16)O(26) crystallize in the monoclinic space group P2(1)/c with a = 8.408(1) A, b = 16.672(1) A, c = 13.901(2) A, beta = 106.33(1) degrees , and Z = 4. The crystal structure consists of a 3D network of the complex borate anion [B(16)O(20)O(12/2)](4-), formed by 12 BO(3) triangles and four BO(4) tetrahedra, which can be viewed as three linked [B(3)O(3)O(4/2)](-) triborate groups bonded to one pentaborate [B(5)O(6)O(4/2)](-) group and two BO(3) triangles. Using this structure, we have performed theoretical calculations using the all-electron full potential linearized augmented plane wave (FP-LAPW) method for the band structure, density of states, electron charge density, and the frequency-dependent optical properties. Our experimental VB-XPS of Sr(2)B(16)O(26) is compared with results of our FP-LAPW calculations. Our calculations show that the valence band maximum (VBM) and conduction band minimum (CBM) are located at Gamma of the Brillouin zone (BZ) resulting in a direct energy gap of about 5.31 eV. Our measured VB-XPS show reasonable agreement with our calculated total density of states for the valence band that is attributed to the use of the full potential method.
Reshak
Ali Hussain
AH
Institute of Physical Biology, South Bohemia University, Nove Hrady 37333, Czech Republic. maalidph@yahoo.co.uk
Auluck
S
S
Kityk
I V
IV
Chen
Xuean
X
D001881:Borates / Q000138:chemical synthesis / Q000737:chemistry*; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D004583:Electrons; D008958:Models, Molecular; D015394:Molecular Structure; D013324:Strontium / Q000737:chemistry*
D001881:Borates; C543851:strontium borate; D013324:Strontium