New interpretation of spectral and photochemical properties of [Fe(CN)5NO]2−

All known assignments of electronic transitions in the Fe(CN)₅NO]^2? ion are inconsistent with the observed characteristics of absorption bands and with the most recent data on photoactivity. Results of more advanced calculations are presented, with Scaled INDO SCF calculations repeated for all excited states separately. In contrast to the older treatments it proves possible to explain why band I is inactive, why irradiation within the band II results in a pure exchange of NO⁺ and H₂O and why irradiation within the frequency range of band IV results in a redox reaction, followed by exchange of NO and H₂O.