The oxidation of Fe(OH)(2) in the presence of Cl- or CO32- ions leads,
in the first stage of the reaction, to chloride-containing green rust
one (GR1), 3Fe(OH)(2) . Fe(OH)(2)Cl . nH(2)O, or carbonate-containing
GR1, 4Fe(OH)(2) Fe-2(OH)(4)CO3 . nH(2)O, respectively. These GR1 comp
ounds give the ferric oxyhydroxides by further oxidation. If a hydroxi
de NixFe1-x(OH)(2) is initially precipitated, the reaction leads to a
nickelous-ferric compound isomorphous to the ferrous-ferric GR1, but s
table with respect to the oxidizing action of air. Similarly, the oxid
ation of a nickelous-ferrous hydroxide, in the presence of excess OH-
ions, leads to a nickelous-ferric GR1, a layered hydroxide with anioni
c interlayers made of OH- ions and water molecules. The Mossbauer spec
tra of these nickelous-ferric GR1 display two ferric doublers, D-0 wit
h IS = 0.34 mm/s and eS = 0.45 mm/s and D-1 with IS = 0.36 mm/s and eS
= 0.86 mm/s. The existence of a ferrous-ferric GR1 incorporating OH-
ions, a compound never observed so far, is strongly suspected.