Hexagonal, Lanthanoid, Rare earth, Photoluminescence spectra

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