Li2Ba4Al2Ta2N8O, the First Barium Nitridoalumotantalate with BCT-Zeolite Type Structure

Single-crystals of Li2Ba4Al2Ta2N8O:Eu2+ were synthesized from Ba3N2, Al2O3, Li3N, Eu2O3, and lithium metal by a high-temperature solid-state reaction in a weld shut tantalum ampule. The crystal structure of Li2Ba4Al2Ta2N8O was determined by single-crystal X-ray diffraction and it crystallizes in the orthorhombic space group Pnnm (no. 58) with the lattice parameters a=1006.71(3), b=1026.58(3), c=607.10(2) pm, and a volume of V=0.62742(3) nm(3). The compound is built up from AlN4 and TaN4 tetrahedra, which form a three-dimensional network corresponding to the BCT-zeolite type structure. Li2Ba4Al2Ta2N8O is homeotypic to Li2Sr4Si4N8O and Li2Sr4Al2Ta2N8O but, additionally, it could be successfully doped with the activator ion Eu2+ and hence features an experimental observed overall emission at lambda(max)=565 nm (fwhm=89 nm) consisting of a superposition of two adjusted emission bands at lambda(max)=557 nm (fwhm=69 nm) and at lambda(max)=604 nm (fwhm=102 nm).

Automated summary

Single-crystals of Li2Ba4Al2Ta2N8O:Eu2+ were synthesized and their crystal structure was determined. The compound features a three-dimensional network with BCT-zeolite type structure and can be doped with Eu2+ activator ions, exhibiting emission at 565 nm.