Abstract: The invention concerns an illumination system comprising a radiation source and a fluorescent material comprising at least one phosphor capable of absorbing part of the light emitted by the radiation source and emitting light of a wavelength different from that of the absorbed light; wherein said at least one phosphor is a yellow to red-emitting europium(II) activated halogeno-oxonitridosilicate of the general formula EaxSiyN2/3X+4/3y:EuzOaXb, wherein 1?x?2; 3?y?7; 0.001?z?0.09, 0.005<a?5 0.05, 0.01<b?0.3, EA is at least one earth alkaline metal chosen from the group of calcium, barium and strontium and X is at least one halogen chosen from the group of fluorine, chlorine, bromine and iodine. The invention is also concerned with a red to yellow-emitting europium(II)-activated halogeno-oxonitridosilicate of the general formula EaxSiyN2/3x+4/3y:EuzOaXb, wherein 1?x?2; 3?y??7; 0.001<z?0.09, 0.005<a?0.05, 0.01<b?0.