Sodium thioantimoniate explained

Sodium thioantimoniate or sodium tetrathioantimonate(V) is an inorganic compound with the formula . The nonahydrate of this chemical,, is known as Schlippe's salt, named after Johann Karl Friedrich von Schlippe (1799–1867). These compounds are examples of sulfosalts. They were once of interest as species generated in qualitative inorganic analysis.

Structure

left|thumb|Anhydrous NaSbS₃ has a complicated structure featuring SbS₄⁻ tetrahedra interconnected by Na-S bonds. Color scheme: red = Sb, yellow = S, violet = Na.The nonahydrate consists of the tetrahedral tetrathioantimonate(V) anions and sodium cations, which are hydrated. The Sb-S distance is 2.33 Å.^{[1] [2]} Related salts are known for different cations including ammonium and potassium.

The anhydrous salt is a polymer with tetrahedral Na and Sb sites.^[3]

Preparation

Sodium tetrathioantimonate nonahydrate is prepared by the reaction of "antimony trisulfide", elemental sulfur, and aqueous sulfide source.^[4]

The Na₂S can be generated in situ by the reaction of sodium hydroxide and S (co-generating sodium sulfate):

Charcoal can also be used to reduce the sulfur.

The required antimony trisulfide is prepared by treatment of Sb(III) compounds with sulfide sources:

Reactions

The hydrate dissolves in water to give the tetrahedral ion. The salt gives antimony pentasulfide upon acidification:

Notes and References

1. Krebs, B., "Thio- and Seleno Compounds of Main Group Elements - New Inorganic Oligomers and Polymers", Angewandte Chemie, 1983, volume 95, pages 113-34.
2. K. Mereiter, A. Preisinger and H. Guth "Hydrogen bonds in Schlippe's salt: refinement of the crystal structures of Na₃SbS₄^.9H₂O by X-ray diffraction and Na₃SbS₄^.9D₂O by neutron diffraction at room temperature" Acta Crystallographica 1979, vol. B35, 19-25. .
3. H. A. Graf, H. Schäfer "Zur Strukturchemie der Alkalisalze der Tetrathiosäuren der Elemente der 5. Hauptgruppe (pages 67–80) Zeitschrift für Anorganische und Allgemeine Chemie 1976, vol. 425, p67-p80.
4. Book: P. W. Schenk. Arsenic, Antimony, Bismuth. Handbook of Preparative Inorganic Chemistry, 2nd Ed. . G. Brauer. Academic Press. 1963. NY, NY. 1pages=618.