Alkaline, Non-disordered, Transitional, Energy gap for direct transition

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