Chalcogen, Rare earth, Hexagonal, Pls

• Al-Eu-N-O-Si
• Al-Ba-Eu-Mg-O
• Ba-Cl-Eu-Gd-O-P
• Al-Ba-Eu-Mg-O-Si
• Ba-Cl-Eu-La-O-P
• chalcogen
• rare earth
• lanthanoid
• luminescent
• nonmetal