Energy level diagram, Nonmetal, Rare earth

• Er-O-Ti
• Al-Ce-O-Y
• Ba-Ce-Cl-Eu-O-P
• Al-Ce-O-Y-Yb
• Al-La-O-Sr-Ta-Yb
• nonmetal
• rare earth
• lanthanoid
• chalcogen
• luminescent
• tetragonal
• cubic
• monoclinic
• trigonal
• hexagonal