Chalcogen, Energy level diagram, Trigonal

• Bi-Na-O-Sm-Ti
• Ca-Eu-O-Sm-Sr-V
• Al-Ca-Eu-O-P
• Bi-Na-O-Pr-Ti
• Er-La-O-S-Yb
• chalcogen
• rare earth
• lanthanoid
• luminescent
• transitional