Eu 2+-doped BaSi 6N 8O phosphors (Ba 1− x Eu x Si 6N 8O, 0.005≤ x≤0.2) were synthesized by gas-pressure sintering of the powder mixture of BaCO 3, Si 3N 4, and Eu 2O 3 at 1750 °C under 0.5 MPa N 2. The fired powder consists of a major BaSi 6N 8O phase and a trace amount of impurity phases. The structural result of the BaSi 6N 8O powder, refined by the Rietveld method, agrees well with that of single crystals. A wide blue luminescence band peaking at about 500 nm is observed in BaSi 6N 8O:Eu 2+, upon excitation with the ultraviolet light of 310 nm. Although Eu is covalently bonded to six nearest neighbor nitrogen atoms, the luminescence of Eu 2+ is not significantly redshifted but shows a very narrow excitation spectrum at high energies. The origin of the short-wavelength luminescence is mainly ascribed to a small crystal-field splitting as a result of extremely long distances between europium and nitrogen ligands in BaSi 6N 8O:Eu 2+.