Luminescent material and light-emitting device

A luminescent material, wherein said luminescent material exhibits a light emission peak in a wavelength ranging from 490 to 580 nm when excited with light having a wavelength ranging from 250 to 500 nm and has a composition represented by the following general formula (2):

• (M1-xRx)a2AlSib2Oc2Nd2 (2)
• wherein in the general formula (2), M comprises Sr;
• R comprises Eu;
• and x, a2, b2, c2 and d2 satisfy the following relationships:
• 0<x≦1, 0.93<a2<1.3, 4.0<b2<5.8
• 0.6<c2<1, and 6<d2<11,
• wherein the luminescent material comprises one component concurrently indicating diffraction peaks at diffraction angles (2θ) of 11.81-11.85, 15.34-15.38, 20.40-20.47 and 23.74-23.86° in the X-ray diffraction in the presence of CuKα characteristic X-rays having a wavelength of 1.54056 Å.