We have synthesized a partially nitridated Ca13.7Eu0.3Mg2Si8O32 (CMSN:Eu2+) using Si3N4 with a conventional solid-state reaction and successfully determined the structural parameters by a combined Rietveld refinement method. The partial nitridation of Ca13.7Eu0.3Mg2Si8O32 (CMS:Eu2+) led to a large enhancement in the luminescence intensity, as much as 148%. From the Rietveld refinement results, the anisotropic changes of the lattice parameters were observed for the partially nitridated samples. By incorporating this phosphor + red phosphor with an encapsulant on an InGaN light-emitting diode (LED) (max=395nm), white light with a color rendering index of 92 and a color temperature of 5320K under 20mA was obtained.