Eight-co-ordination. Part IV. The structures of the octacyanide complexes of quadri- and quinque-valent molybdenum and tungsten

Abstract

The Raman spectra of solid K₄M(CN)₈,2H₂O (M = Mo, W) in the C–N stretching region agree with the previously determined i.r. spectra, supporting the dodecahedral configuration for the anions. The Raman spectra of aqueous solutions differ from those of the solid salts, and a square antiprismatic structure is postulated. The spectra of solid Tl₄W(CN)₈ are consistent with a dodecahedral configuration, and the values of the C–N stretching frequencies suggest that there is some interaction with the cation. The Raman, i.r., and e.s.r. spectra of solid [Co(NH₃)₆][M(CN)₈](M = Mo, W) are interpreted in terms of a square antiprismatic configuration for the anions.