Nontypical Luminescence Properties and Structural Relation of Ba3P5N10X:Eu2+ (X = Cl, I): Nitridophosphate Halides with Zeolite-like Structure

The isotypic nitridophosphates Ba3P5N10X (X = Cl, I) have been synthesized by high-temperature reaction under pressures between 1 and 5 GPa. The crystal structures of both compounds were solved and refined using single-crystal X-ray diffraction data. Accuracy of the structure determination as well as phase purity of the products were confirmed by Rietveld refinement and FTIR spectroscopy. The band gap values (4.0–4.3 eV) for the direct transitions were determined from UV–vis data using the Kubelka–Munk function and were confirmed by DFT calculations. Both compounds crystallize in the Ba3P5N10Br structure type (space group Pnma (No. 62), Z = 8; Ba3P5N10Cl, a = 12.5182(5) A, b = 13.1798(5) A, c = 13.7676(6) A, R1 = 0.0214, wR2 = 0.0526; Ba3P5N10I, a = 12.6311(7) A, b = 13.2565(8) A, c = 13.8689(8) A, R1 = 0.0257, wR2 = 0.0586) with a tetrahedra network being analogous to the topology of the JOZ zeolite structure type. The crystal structure is built up of all-side vertex-sharing PN4 tetrahedra leading to a z...