2K 2 FeO 4 þ 5H 2 O ! 2Fe OH
ð Þ 3 þ 4KOH þ 3=2O 2
ð8:4Þ
Dissolving ferrate(V) in water leads to fast disproportionation of Fe(V) into Fe
(III) and Fe(VI). Formation of Fe(IV) during the process was not confirmed. Charge
disproportionation and reduction of the ferrate compete in the process; therefore, the
Fe(III)/Fe(VI) ratio is not typically 1:2 but quite close to 1:1. Thus, the transformation can be described by chemical equation
2K 3 FeO 4 þ 3=2H 2 O ! KFeO 2 þ K 2 FeO 4 þ 3KOH þ 1=4O 2
ð8:5Þ
Fig. 8.4 Kinetics of
transformation of solid
potassium ferrate(VI) at
room temperature in air
expressed as dependence of
Mössbauer spectral area of
the ferrate subspectrum on
the relative humidity ((a)
lowest RH; (b) higher RH
levels; (c) dependence of the
second step decay rate on
the relative humidity).
(Reprinted with permission
from Machala et al. (2009).
Copyright (2009) WileyVCH Verlag GmbH &
Co. KGaA, Weinheim)
184
L. Machala et al.
ð Þ 3 þ 4KOH þ 3=2O 2
ð8:4Þ
Dissolving ferrate(V) in water leads to fast disproportionation of Fe(V) into Fe
(III) and Fe(VI). Formation of Fe(IV) during the process was not confirmed. Charge
disproportionation and reduction of the ferrate compete in the process; therefore, the
Fe(III)/Fe(VI) ratio is not typically 1:2 but quite close to 1:1. Thus, the transformation can be described by chemical equation
2K 3 FeO 4 þ 3=2H 2 O ! KFeO 2 þ K 2 FeO 4 þ 3KOH þ 1=4O 2
ð8:5Þ
Fig. 8.4 Kinetics of
transformation of solid
potassium ferrate(VI) at
room temperature in air
expressed as dependence of
Mössbauer spectral area of
the ferrate subspectrum on
the relative humidity ((a)
lowest RH; (b) higher RH
levels; (c) dependence of the
second step decay rate on
the relative humidity).
(Reprinted with permission
from Machala et al. (2009).
Copyright (2009) WileyVCH Verlag GmbH &
Co. KGaA, Weinheim)
184
L. Machala et al.