Crystal structure and luminescence properties of the barium europium tetragermanate Ba2Eu2Ge4O13

The tetragermanate Ba₂Eu₂Ge₄O₁₃ was synthesized for the first time, and its structural and luminescent properties were examined. It crystallizes in a monoclinic system (space group C2/c, Z=4) and its crystal structure incorporates a unique linear [Ge₄O₁₃]¹⁰⁻ anion. The photoluminescence spectrum of the sample (λ_ex=280nm) contains several intense peaks in the orange-red spectral range corresponding to the 4f–4f transitions in Eu³⁺ ions.