ENVIRONMENT OF INTERSTITIAL IONS IN A PRUSSIAN BLUE ANALOG CO3[CO(CN)6]2

Magnetic data indicate that interstitial Co2+ is present as a high-spin octahedral complex in the pink solid Co3[Co(CN)6]2·xH2O. Visible and infrared spectra of this pink hydrate, along with changes in these spectra and of magnetic moments upon dehydration, indicate the octahedral interstitial complex is Co(H2O6)2+. Previous pressure-composition studies on similar Prussian blue analogs are discussed. Contrary to an earlier interpretation, a smooth decrease in pressure with decreasing water content does not imply the absence of discrete species such as M(H26)2+ Since NH3 should form a stronger complex than water and adsorb less readily, a study was carried out on the system NH3-Co3[Co(CN)6]2. The absorption isotherms demonstrate the existence of Co3[Co(CN)6]2 · 6NH3, for which stoichiometry and infrared data indicate the presence of Co(NH3)e2+ interstitial complexes. © 1969, American Chemical Society. All rights reserved.