Abstract: The emission spectra of some heteropolytungstates containing europium, K_{17[Eu(XW11 O39)2](X = P, Ge, As, or Ga), K17[EuCAs2W17O61)2/sup>] and K16H9EuAs4W40O140 have been investigated and the structures of these compounds are discussed. The emission spectra at room temperature are very similar to each other in terms of both the number of bands and transition frequencies, showing that they have the similar structures to those of K16[Ce(P2W17O61)2] and K12[U(GeW11O39)2].}

Key words: Emission spectrum, Heteropolytungstates containing europium, Lanthanides