Phosphor from the class of the oxynitridosilicates, having a cation M which is doped with divalent europium, and having the empirical formula MSi.sub.2O.sub.2N.sub.2, where M=Sr.sub.1-x-yCa.sub.yEu.sub.x where 0.3.ltoreq.x+y.ltoreq.0.725, with a Ca/Eu ratio of >1, the oxynitridosilicate having an emission with a dominant wavelength in the range from 555 to 568 nm.