This interpretation agrees well with previous absorption spectra of tetrahedral [CoBr4] 2-in a tetrabutylammonium [CoBr4] 2-complex. As such, the octahedral Co atoms surrounded by carbonyls should absorb at smaller wavelengths (higher energies) due to its expected larger splitting (based on the spectrochemical series) and higher coordination state. This interpretation implies that only the Co-hmba network is reorganized during the melt-quenching procedure, while the charge compensating [CoBr4] 2-units remain stable both in the pristine and hydrated glasses.