Tetramethyl ammonium ferro-heptanitroso sulphide, N(CH₃)₄.Fe₄(NO)₇S₃

Tetramethyl ammonium ferro-heptanitroso sulphide, N(CH₃)₄.Fe₄(NO)₇S₃, yields triclinic crystals: -

a: b: c = 0.8648: 1: 1.3125. α = 87° 29.5'. β = 106° 7'. γ = 93° 44'. Density, 2.056.

The tetra-ethyl salt is likewise triclinic, possessing the following crystallographic elements: -

a: b: c = l.0221: 1: 1.0247. α = 85° 8'. β = 97° 8'. γ = 99° 17.5'. Density, 1.883.

Heptanitroso ferro-sulphides of the following metals have also been obtained: -

Caesium, CsFe₄(NO)₇S₃.H₂O,
Rubidium, RbFe₄(NO)₇S₃.H₂O, and
Thallium, TlFe₄(NO)₇S₃.H₂O.

Of these the first-named is readily obtained by adding a solution of caesium chloride to one of sodium heptanitroso ferro-sulphide, when the caesium derivative is precipitated as an insoluble black crystalline powder. The rubidium derivative, obtained in an analogous manner, presents a similar appearance. The thallium salt is likewise difficultly soluble in water, and is obtained by double decomposition with thallium sulphate and the potassium derivative.

The hydrazine, N₂H₄.Fe₄(NO)₇S₃, and the hydroxylamine, NH₂OH.Fe₄(NO)₇S₃, derivatives have been prepared.