Energy level diagram, Nonmetal, Rare earth, Tetragonal

• Er-O-V-Y-Yb
• F-Li-U-Y
• Er-Gd-O-V-Yb
• Ca-Eu-O-W
• Er-Eu-Mg-O-Si-Sr
• rare earth
• nonmetal
• luminescent
• lanthanoid
• chalcogen