Europium valency in EuCu(2-x)Fe(x)Si(2), EuCu(2)Si(2-x)Ge(x), EuCu(2-x)Si(2+x) and EuNi(2-x)Si(2+x).

Mossbauer spectroscopy, X-ray photoemission spectroscopy and magnetization studies of EuCu(2-x)Fe(x)Si(2), EuCu(2)Si(2-x)Ge (x), EuCu(2-x) Si(2+x) and EuNi(2-x)Si(2+x) have been performed. In EuFe(2)Si(2) and EuNi(2)Si(2) the Eu ion is trivalent, in EuCu(2)Si(2) it is of intermediate valency. In all systems with x=0 many inequivalent Eu sites of intermediate valency are formed. In EuCu(2-x)Fe(x)Si(2) the average valency of Eu moves nonmonotonicaly towards Eu(3+. In EuCu(2)Si(2-x)Ge (x), EuCu(2-x)Si(2+x) and EuNi(2-x)Si(2+x) the Eu average valency moves quickly towards Eu(2+). In all three systems, when x=1, all Eu ions are already stable divalent.