Crystal Structure and Luminescence Properties of the First Hydride Oxide Chloride with Divalent Europium: LiEu ₂2 HOCl ₂2

摘要

> The mixed‐anionic hydride oxide chloride LiEu ₂ HOCl ₂ with divalent europium was synthesized by the reduction of Eu ₂ O ₃ with LiH in a LiCl flux at 750 °C for 4 d in silica‐jacketed niobium capsules. According to structure determination by single‐crystal X‐ray diffraction the yellow compound crystallizes in the orthorhombic space group Cmcm ( a = 1492.30(11) pm, b = 570.12(4) pm, c = 1143.71(8) pm, Z = 8) with a crystal structure closely related to that one of the quaternary hydride oxide LiLa ₂ HO ₃ and the hydride nitride LiSr ₂ H ₂ N. On the other hand it can also be derived from the PbFCl‐type structure of EuHCl showing astonishingly short Eu 2+ ···Eu 2+ contacts of 326 and 329 pm. Both crystallographically different Eu 2+ cations have nine anionic neighbors, while all other ions (Li + , H – , O 2– and Cl – ) reside in six‐membered coordination spheres. LiEu ₂ OCl ₂ H exhibits a bright yellow luminescence with an emission maximum at 581 nm upon excitation at 440 nm.