Nitridomagnesosilicate Ba[Mg3SiN4]:Eu2+ and Structure-Property Relations of Similar Narrow-Band Red Nitride Phosphors

The nitridomagnesosilicate Ba[Mg3SiN4] has been synthesized in an arc-welded Ta ampule. The crystal structure was solved and refined from single-crystal X-ray data and Rietveld refinement on the basis of powder X-ray diffraction data, revealing a distorted triclinic variant of the UCr4C4 structure type (space group P (1) over bar (no. 2), Z = 1, a = 3.451(1), b = 6.069(5), c = 6.101(4) angstrom, alpha = 85.200(7), beta = 73.697(5), gamma = 73.566(8)degrees, R-p = 0.0218, R-wp = 0.0290). The crystal structure of Ba[Mg3SiN4] consists of a highly condensed network of (Mg,Si)N-4 tetrahedra with Ba2+ centered inside vierer ring channels along [100] in a cuboidal coordination by N3-. From UV/vis-reflectance data, a band gap of similar to 4.0 eV was estimated. Doping with Eu2+ shows promising luminescence properties of lambda(em) = 670 nm with an fwhm similar to 1970 cm(-1). Furthermore, anomalous luminescence phenomena, such as trapped-exciton emission, were identified and considered. Ba[Mg3SiN4]:Eu2+ is a further narrow-band red-emitting phosphor and is discussed concerning the structure-property relations of recently reported Eu2+-doped nitrides with narrow-band red emission.