Fougèrite is a relatively recently described naturally-occurring green rust mineral. It is the archetype of the [url]http://fougèrite group[/url]
in the larger [url]http://hydrotalcite supergroup[/url]
of naturally-occurring [url]http://layered double hydroxides[/url]
.[url]http://[1][/url]
The structure is based on http://brucite-like layers containing Fe2+
and Fe3+
cations, O2-
and OH-
anions, with loosely bound [CO3
]2-
groups and H2
O molecules between the layers. Fougèrite crystallizes in http://trigonal system. The ideal formula for fougèrite is [Fe2+4
Fe3+2
(OH)12
][CO3
]·3H2
O. Higher degrees of oxidation produce the other members of the fougèrite group, namely [url]http://trébeurdenite[/url]
, [Fe2+2
Fe3+4
O2
(OH)10
][CO3
]·3H2
O and [url]http://mössbauerite[/url]
, [Fe3+6
O4
(OH)8
][CO3
]·3H2
O.【摘自维基百科】