Li(2)Ba(4)Al(2)Ta(2)N(8)O, the First Barium Nitridoalumotantalate with BCT‐Zeolite Type Structure

Single‐crystals of Li(2)Ba(4)Al(2)Ta(2)N(8)O:Eu(2+) were synthesized from Ba(3)N(2), Al(2)O(3), Li(3)N, Eu(2)O(3), and lithium metal by a high‐temperature solid‐state reaction in a weld shut tantalum ampule. The crystal structure of Li(2)Ba(4)Al(2)Ta(2)N(8)O 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 AlN(4) and TaN(4) tetrahedra, which form a three‐dimensional network corresponding to the BCT‐zeolite type structure. Li(2)Ba(4)Al(2)Ta(2)N(8)O is homeotypic to Li(2)Sr(4)Si(4)N(8)O and Li(2)Sr(4)Al(2)Ta(2)N(8)O but, additionally, it could be successfully doped with the activator ion Eu(2+) and hence features an experimental observed overall emission at λ(max)=565 nm (fwhm=89 nm) consisting of a superposition of two adjusted emission bands at λ(max)=557 nm (fwhm=69 nm) and at λ(max)=604 nm (fwhm=102 nm).