Energy level diagram, Nonmetal

• Er-O-Ti
• Al-Ce-O-Y
• Al-Mg-O-Ti
• Al-Ce-O-Y-Yb
• Al-La-O-Sr-Ta-Yb
• nonmetal
• lanthanoid
• rare earth
• chalcogen
• transitional
• cubic
• tetragonal
• monoclinic
• trigonal
• hexagonal