Iron(II) hydroxide
Iron(II) hydroxide or ferrous hydroxide is an inorganic compound with the formula Fe(OH). It is produced when iron(II) salts, from a compound such as iron(II) sulfate, are treated with hydroxide ions. Iron(II) hydroxide is a white solid, but even traces of oxygen impart a greenish tinge. The air-oxidized solid is sometimes known as "green rust".
Aluminium hydroxide
The naming for the different forms of aluminium hydroxide is ambiguous and there is no universal standard. All four polymorphs have a chemical composition of aluminium trihydroxide (one aluminium atom attached to three hydroxide groups).