Abstract L III absorption edges of cerium in ternary AuCu 3 compounds Ce(Pd 1− x M x ) 3 ( M = Ag and Rh) and (Ce 1− x Y x )Pd 3 are presented. We find that Ce in these compounds is mixed valent with n f ⩾ 0.7. The valence V of Ce(Pd 1− x Rh x ) 3 becomes concentration independent of V = 3.29 ± 0.02 for x ⩾ 0.18. In Ce 1− x Y x Pd 3 we observe the valence to increase up to V = 3.32 ± 0.02 at the highest concentration of Y. We show, that a critical volume, available for the Ce atom, is associated with the concentration independent valence around 3.3. For both systems, linewidths W 1, W 0 and Δ = E(4 f 1) − E(4 f 0), as derived from L III double-bump structure, are given. Possible falsifications due to “final states effects” on the valence are discussed.