Alkaline, Chalcogen, Energy gap for direct transition

• Mg-O
• O-Sr-Ti
• Mg-O-Zn
• Ba-Cu-F-O-Y
• Mg-Se
• alkaline
• chalcogen
• non-disordered
• conductor
• semiconductor
• cubic
• tetragonal
• orthorhombic
• hexagonal
• trigonal