On the Red Intermediate in a Photochemical Reaction of the Mo(CN)84° Ion

There is a disagreement in the literature as to the intermediates and final products of the photo­ chemical reaction of diluted aqueous solutions of K4Mo (CN) 8 . In the article we give arguments to support our view that the formula of the red intermediate ion is [Mo(CN)8(H2O)2] 40. In parti­ cular we give an answer to recent objections by P e r u m a r e d d i against such an interpretation. In the theoretical part we also reconsider K ö n i g’s interpretation of the electronic spectrum of [Mo(CN)8] 40, in terms of a flattened Archimedean antiprism.