Phosphors comprising a nitride-based composition represented by the chemical formula: M(x/v)(M′aM″b)Si(c−x)AlxNd:RE, wherein: M is a divalent or trivalent metal with valence v; M′ is at least one divalent metal; M″ is at least one trivalent metal; 2a+3b+4c=3d; and RE is at least one element selected from the group consisting of Eu, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb. Furthermore, the nitride-based composition may have the general crystalline structure of M′aM″bSicNd, where Al substitutes for Si within the crystalline structure and M is located within the crystalline structure substantially at the interstitial sites.