Europium Lithosilicates Li 2 EuSi 2 N 4 and Li 2 EuSiO 4 -Crystal Structures and Luminescence

With Li EuSi N , the end member of the solid-solution series set up by substituting the divalent cation in the well-known host materials Li CaSi N and Li SrSi N with Eu(II) could be synthesized and described by means of single-crystal X-ray diffraction and single-grain luminescence spectroscopy. The new compound crystallizes isotypically to Li CaSi N and Li SrSi N in cubic space group 3̅ (no. 205) with a lattice parameter of = 10.7049(2) Å and a cell volume of = 1226.73(7) Å . Irradiated with blue light, Li EuSi N exhibits a narrow-band red emission (λ = 628 nm, 1.97 eV, 15924 cm ; fwhm = 83 nm, 0.27 eV, 2143 cm ). Also for Li EuSiO , the end member of the solid-solution series of Li SrSiO with Sr(II) substituted by Eu(II), luminescence emission could be measured on a single crystal (λ = 595 nm, 2.05 eV, 16798 cm ; fwhm = 116 nm, 0.40 eV, 3211 cm ). In this paper, both compounds are being compared with other known members of their solid-solution series regarding structure and luminescence properties.