Energy level diagram, Lanthanoid, Transitional, Monoclinic

• Er-La-O-V-Yb
• Er-O-Si-Tm-Y-Yb
• Er-O-W-Y-Yb
• Er-O-W-Y
• Ba-Bi-Eu-Gd-Li-Mo-O
• transitional
• lanthanoid
• rare earth
• chalcogen
• luminescent