The electronic ground state of isolated Cr3+ introduced into the title compounds has been investigated with electron spin resonance and electron-nuclear double resonance spectroscopy. Simultaneously a multiple scattering (MS) Xalpha study of the (CrCl6)3− cluster has been performed. The experimental results agree with a cubic Cr site. They further show evidence for strong quadrupole interaction at the anion neighbor nuclei and for observably different covalency in the two hosts. Rather good agreement is found between the predictions of the MS Xalpha model and the experimental superhyperfine interaction constants but not with the Cr-hyperfine structure constant. It is suspected that the second neighboring Cs play a non-negligible role in the electronic structure of the cluster.