Alkali, Chalcogen, Nonmetal, Optical properties, Trigonal

• Li-Nb-O
• Li-O-Ta
• Bi-Na-O-Ti
• Fe-K-Mo-O
• Li-Mg-Nb-O
• phonons
• luminescence
• optical absorption
• wavenumber of optical phonon
• photoluminescence spectra
• chalcogen
• alkali
• nonmetal
• transitional
• disordered