ИСТИНА

It is known that the use of isomer shift (IS) for the identification of iron oxidation state (OS) encounters several difficulties. In particular, IS of [Fe(CN)6]3- is in between of ISs of [Fe(CN)5(NO)]2- and [Fe(CN)6]4-. At the same time we do not know any direct evidences confirming that iron in [Fe(CN)6]3- is in trivalent state. If we begin to refer the mentioned anions to the row of divalent iron complexes: [Fe(CN-)5(NO+)]2-, [Fe(CN-)5(CN0)]3- and [Fe(CN-)5(CN-)]4-, it allows us to simplify the interpretation. Thus, Mossbauer spectroscopy is in sore need of reliable reference substances with well-established properties. Ferrates are the important reference substances for Mossbauer spectroscopy because they form the unique row of similar iron particles comprising today four different OS! The dependency IS vs. iron OS shows the linear regression: IS(alpha-Fe)=-0.33*OS + 1.09 [mm/s]. We presume, that the coefficient 0.33 mm/s corresponds to the addition of one electron to the iron valent shell in a wide range of compounds.