Iron hexaammine complexes

Fe(NH3)6]Br2 When an excess of gaseous ammonia is passed through a freshly prepared solution of elemental iron in hydrobro-mic acid (40%), the bromide salt of the hexaammine iron(II) complex is deposited (86). The cation is also found in certain carbonyl ferrates, such as [Fe(NH3)6][Fe3(CO)u], which are obtained from the reaction of triiron dodecacarbonyl with ammonia in an autoclave (87). 

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