Divalent doping of the EuPd3S4 mixed valence system

We investigate the solubility of divalent alkaline earths calcium and strontium in EuPd3S4 where Eu2+ and Eu3+ ions are present in equal amounts on distinct sublattices. Contrary to a recent yttrium and lanthanum substitution study where complete europium replacement is possible, and there are significant changes in the europium valence, here we observe severely limited solubility (x≲0.1 (Ca) and x≲0.25 (Sr) ) with a simple direct replacement of Eu2+ ions and no effects on the europium valence.