Hexagonal, Lanthanoid, Photoluminescence spectra

• Al-Ba-Eu-Mg-O
• Er-F-Gd-Na-Yb
• F-Gd-Ho-Na-Yb
• Ba-Cl-Eu-O-P
• Er-F-Na-Y-Yb
• rare earth
• lanthanoid
• luminescent
• chalcogen
• alkaline