Sodium thioantimoniate

Sodium thioantimoniate or sodium tetrathioantimonate(V) is an inorganic compound with the formula Na₃SbS₄. The nonahydrate of this chemical, Na₃SbS₄·9H₂O, 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.

Sodium thioantimoniate

Sodium thioantimoniate
Names
IUPAC name Sodium tetrathioantimonate(V)
Identifiers
CAS Number	10101-91-4 (nonahydrate)
3D model (JSmol)	(nonahydrate): Interactive image
ChemSpider	34995828 (nonahydrate)
ECHA InfoCard	100.208.207
EC Number	682-752-5 (nonahydrate)
PubChem CID	71312650 (nonahydrate)
UNII	ZLI1AS68EX (nonahydrate)
CompTox Dashboard (EPA)	DTXSID00746895 (nonahydrate)
InChI InChI=1S/3Na.9H2O.4S.Sb/h;;;9*1H2;;;;;/q3*+1;;;;;;;;;;;3*-1; Key: ZHSCVFVPXYYCAW-UHFFFAOYSA-N
SMILES (nonahydrate): O.O.O.O.O.O.O.O.O.[Na+].[Na+].[Na+].[S-][Sb](=S)([S-])[S-]
Properties
Chemical formula	Na3SbS4 (anhydrous) Na3SbS4·9H2O (nonahydrate)
Molar mass	272.13 g·mol−1 (anhydrous) 434.27 g·mol−1 (nonahydrate)
Appearance	Yellow crystals
Density	1.806 g/cm3, solid
Melting point	87 °C (189 °F; 360 K)
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H332, H411
Precautionary statements	P261, P264, P270, P271, P273, P301+P312, P304+P312, P304+P340, P312, P330, P391, P501
Related compounds
Other cations	Potassium thioantimoniate
Related compounds	Antimony(III) sulfide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Structure

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 SbS3−4 and sodium cations Na⁺, 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]

3 Na₂S + 2 S + Sb₂S₃ + 18 H₂O → 2 Na₃SbS₄·9H₂O

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

Sb₂S₃ + 8 NaOH + 6 S → 2 Na₃SbS₄ + Na₂SO₄ + 4 H₂O

Charcoal can also be used to reduce the sulfur.

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

2 SbCl₃ + 3 H₂S → Sb₂S₃ + 6 HCl

Reactions

The hydrate dissolves in water to give the tetrahedral SbS3−4 ion. The salt gives antimony pentasulfide upon acidification:

2 Na₃SbS₄ + 6 HCl → Sb₂S₅ + 6 NaCl + 3 H₂S