Europium-substituted compounds of Ba_1-xY_2-yEu_x+ySi₃O₁₀ and Ba_1-xLu_x-yEu_x+ySi₃O₁₀ have been prepared as 1 efficient green phosphors fur use in solid state white lighting.  The compounds were prepared using a high-temperature solid state route and characterized by powder X-ray diffraction and flourescence spectroscopy.  Photoluminescent characterization identified a broad excitation peak ranging from <250 nm to 400 nm (UV to deep blue) and a broad emission across nearly the entire visible region that varied depending on Eu²⁺ concentration.  The emissions cover from about 400 nm to >600 nm, producing a greenish-white light.  The optimized quantum yield for both compounds is approximately 30% with an optimized Eu²⁺ concentration of 3% and 1% respectively, which is comparable with other broad emission phosphors.