Arsenic pentasulfide

Arsenic pentasulfide
Names
	IUPAC name Arsenic pentasulfide
	Other names Arsenic(V) sulfide; Diarsenic pentasulfide
Identifiers
CAS Number	1303-34-0;
3D model (JSmol)	Interactive image; Interactive image;
ChemSpider	2617071;
ECHA InfoCard	100.154.195
EC Number	625-728-1;
PubChemCID	3371533;
UNII	QT80493YBG;
UN number	1557
CompTox Dashboard(EPA)	DTXSID0058302;
	InChI InChI=1S/As2S5/c3-1(4)7-2(5)6 Key: AYRZLUSHOXJGKY-UHFFFAOYSA-N; InChI=1S/As4S10/c5-1-9-2(6)12-3(7,10-1)14-4(8,11-1)13-2 Key: CHQYGMAMCBQSIU-UHFFFAOYSA-N;
	SMILES S=[As](=S)S[As](=S)=S; S=[As]12S[As]3(=S)S[As](=S)(S1)S[As](=S)(S2)S3;
Properties
Chemical formula	As2S5
Molar mass	310.14g·mol−1
Appearance	Vivid, dark orange, opaque crystals
Melting point	300 °C (572 °F; 573 K)(minimum)
Boiling point	500 °C (932 °F; 773 K)(decomposes)
Solubility in water	0.014 g dm−3(at 0 °C)
Hazards
	GHSlabelling:
Pictograms
Signal word	Danger
Hazard statements	H301,H331,H410
Precautionary statements	P261,P264,P270,P271,P273,P301+P310,P304+P340,P311,P321,P330,P391,P403+P233,P405,P501
Related compounds
Related compounds	Arsenic pentoxide; Arsenic trisulfide; Phosphorus pentasulfide
	Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa). verify(what is?) Infobox references

Arsenic pentasulfideis aninorganic compoundcontaining arsenic and sulfur.^[1]

Uses

Solids of the approximate formulaAs₂ S₅have been used aspigmentsand chemical intermediates but are generally only of interest in academic laboratories.^[2]

Preparation

Arsenic pentasulfide is prepared by precipitation from an acidic solution of soluble As(V) salts by treatment withhydrogen sulfide.^[3]It may be also prepared by heating a mixture of arsenic and sulfur, extracting the fused mass with anammoniasolution and reprecipitating arsenic pentasulfide at low temperature by addition ofhydrochloric acid.

Phosphorus pentasulfidewith the formula P₄S₁₀,is a molecular compound featuring tetrahedral phosphorus(V) centres. Trends in arsenic redox potentials suggest that As₂S₅adopts a similar structure, a plausible alternative being an arsenic polysulfide.

Reactions

Arsenic pentasulfide hydrolyzes in boiling water, givingarsenous acidandsulfur:

As₂S₅+ 6 H₂O → 2 H₃AsO₃+ 2 S + 3 H₂S

It oxidizes in air at elevated temperatures producing arsenic oxides, the products and yields of which are variable. In alkali metal sulfide solutions arsenic pentasulfide forms athioarsenateanion, [AsS₄]³⁻,which contain As(V) centres.

References

^Greenwood, Norman N.;Earnshaw, Alan (1997).Chemistry of the Elements(2nd ed.).Butterworth-Heinemann.ISBN 978-0-08-037941-8.
^A. L. Emelina, A. S. Alikhanian, A. V. Steblevskii and E. N. Kolosov "Phase diagram of the As-S system" Inorganic Materials, 2007, Volume 43, pages95-104,doi:10.1134/S002016850702001X
^Norman., N. C., ed. (1998).Chemistry of arsenic, antimony and bismuth.London: Blackie Acad. & Professional. pp. 114–115.ISBN 978-0-7514-0389-3.

[1] Greenwood, Norman N.;Earnshaw, Alan (1997).Chemistry of the Elements(2nd ed.).Butterworth-Heinemann.ISBN 978-0-08-037941-8.

[2] A. L. Emelina, A. S. Alikhanian, A. V. Steblevskii and E. N. Kolosov "Phase diagram of the As-S system" Inorganic Materials, 2007, Volume 43, pages95-104,doi:10.1134/S002016850702001X

[3] Norman., N. C., ed. (1998).Chemistry of arsenic, antimony and bismuth.London: Blackie Acad. & Professional. pp. 114–115.ISBN 978-0-7514-0389-3.

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v t e Arseniccompounds
Arsenides	AlAs BAs BiAs Cd₃As₂ CaAs CoAs DyAs HoAs GaAs InAs YAs LiAs MoAs₂ MnAs NpAs NpAs₂ PdAs₂ PrAs PuAs SmAs Na₃As TaAs WAs₂ YAs Zn₃As₂
As(III)	AsBr₃ AsCl₃ AsCl₅ AsF₃ AsH₃ AsI₃ As₂O₃ As₂S₃ As₂Se₃ As₄S₄ AsP
As(III,V)	As₂O₄
As(V)	AsF₅ AsCl₅ As₂O₅ As₂S₅