Dinitrosyl iron complexes [E5Fe(NO)2]− (E = S, Se): A precursor of Roussin's black salt [Fe4E3(NO)7]−

Dinitrosyl iron complex [Se5Fe(NO)2]− with EPR signal of g = 2.064 at 298 K, a precursor of [Fe4Se3(NO)7]−, was obtained from the reaction of [Fe(CO)3(NO)]− and Se.