Zusammenfassung
The chalcogenogallate RbGaSe2 was synthesized by thermal decomposition of rubidium azide in the presence of gallium selenide and selenium. RbGaSe2 crystallizes in the monoclinic space group C2/c (no. 15) with the lattice parameters a = 10.954(1) angstrom, b = 10.949(1) angstrom, c = 16.064(1) angstrom, beta = 99.841(4)degrees, V = 1898.2(2) angstrom(3), and Z = 16 (single-crystal data, 20 degrees ...
Zusammenfassung
The chalcogenogallate RbGaSe2 was synthesized by thermal decomposition of rubidium azide in the presence of gallium selenide and selenium. RbGaSe2 crystallizes in the monoclinic space group C2/c (no. 15) with the lattice parameters a = 10.954(1) angstrom, b = 10.949(1) angstrom, c = 16.064(1) angstrom, beta = 99.841(4)degrees, V = 1898.2(2) angstrom(3), and Z = 16 (single-crystal data, 20 degrees C) in the TlGaSe2 structure type. Its crystal structure features anionic layers (2)(infinity)[Ga4Se84-] with a van der Waals distance of 3.30(1) angstrom. Thermal analysis revealed a melting point of about 930 degrees C. Using UV/Vis diffuse reflectance spectroscopy, a wide bandgap of 3.16 eV was determined for the colorless semiconductor. The bonding situation in the compound was further compared with the isotypic cesium phases based on the results from Raman spectroscopy and DFT calculations. The slight shifts of the Raman bands suggest a slightly higher covalency of the rubidium compound.