Alkali, Chalcogen, Optical absorption, Trigonal

• Li-Nb-O
• Li-Mg-Nb-O
• Dy-Li-Nb-O
• Fe-Li-Nb-O
• Cd-Cs-In-Se
• values of optical absorption
• transmittance
• alkali
• chalcogen
• transitional
• disordered
• nonmetal