Sodium pyrosulfate

Sodium pyrosulfate^[1]
Names

IUPAC name Disodium disulfate
Other names Sodium pyrosulphate; Disulfuric acid disodium salt, disodium disulfate; Sodium metabisulfate
Identifiers
CAS Number	13870-29-6^Y
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL111016^Y
ChemSpider	7970254
ECHA InfoCard	100.034.190
EC Number	237-625-5
PubChem CID	9794487
CompTox Dashboard (EPA)	DTXSID60889631
InChI InChI=1S/2Na.H2O7S2/c;;1-8(2,3)7-9(4,5)6/h;;(H,1,2,3)(H,4,5,6)/q2*+1;/p-2 Key: JXAZAUKOWVKTLO-UHFFFAOYSA-L
SMILES [Na+].[Na+].[O-]S(=O)(=O)OS(=O)(=O)[O-]
Properties
Chemical formula	Na₂S₂O₇
Molar mass	222.12 g/mol
Appearance	Translucent white crystals
Density	2.658 g/cm³
Melting point	400.9 °C (753.6 °F; 674.0 K)
Boiling point	decomposes at 460 °C (860 °F; 733 K)
Solubility in water	hydrolyses^[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is ^YN ?) Infobox references

Chemical compound

Sodium pyrosulfate is an inorganic compound with the chemical formula of Na₂S₂O₇.^[1] It is a colorless salt.^[3] It hydrolyses in water to form sodium bisulfate with a chemical formula of NaHSO4 which has a pH of around 1.

Preparation

Sodium pyrosulfate is obtained by the dehydration of sodium bisulfate:^[4]^[5]

2 NaHSO₄ → Na₂S₂O₇ + H₂O

Temperatures above 460 °C further decompose the compound, producing sodium sulfate and sulfur trioxide:

Na₂S₂O₇ → Na₂SO₄ + SO₃

Applications

Sodium pyrosulfate was used in analytical chemistry. Samples are fused with sodium pyrosulfate to ensure complete dissolution before a quantitative analysis.^[6]^[7]

References

^ ^a ^b Olsen, J. C., ed. (1934). Van Nostrand's Chemical Annual. London: Chapman and Hall.
^ Heinz K. Hofmeister; John R. Van Wazer (1962). "Hydrolysis of Sodium Pyrosulfate". Inorganic Chemistry. 1 (4). ACS: 811–812. doi:10.1021/ic50004a019.
^ Helmold Plessen (2000). "Sodium Sulfates". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a24_355. ISBN 978-3527306732.
^ Noyes, William (1913). A Textbook of Chemistry. New York: Henry Holt and Company. p. 186. Retrieved 13 January 2016.
^ von Plessen, Helmold (2000). "Sodium Sulfates". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a24_355. ISBN 9783527303854.
^ Nemodruk, Aleksandr; Karalova, Zinaida (1969). Analytical chemistry of boron: Analytical chemistry of the elements. Charlottesville, VA: Ann Arbor-Humphrey Science Publishers. pp. 23 & 193. ISBN 9780250399192.
^ Kiely, P. V.; Jackson, M. L. (1965). "Quartz, Feldspar, and Mica Determination for Soils by Sodium Pyrosulfate Fusion". Soil Science Society of America Journal. 29 (2): 159–163. Bibcode:1965SSASJ..29..159K. doi:10.2136/sssaj1965.03615995002900020015x.

Sodium compounds

Inorganic

Halides	NaF NaHF₂ NaCl NaBr NaI NaAt
Chalcogenides	NaO₃ NaO₂ Na₂O Na₂O₂ NaOH NaOD Na₂S NaSH Na₂Se NaSeH Na₂Te NaHTe Na₂Po
Pnictogenides	Na₃N NaN₃ NaNH₂ Na₃P Na₃As
Oxyhalides	NaClO NaClO₂ NaClO₃ NaClO₄ NaBrO NaBrO₂ NaBrO₃ NaBrO₄ NaIO₃ NaIO₄
Oxychalcogenides	Na₂SO₃ Na₂SO₄ NaHSO₃ NaHSO₄ Na₂S₂O₃ Na₂S₂O₄ Na₂S₂O₅ Na₂S₂O₆ Na₂S₂O₇ Na₂S₂O₈ Na₂SeO₃ Na₂SeO₄ NaHSeO₃ Na₂TeO₃
Oxypnictogenides	NaNO₂ NaNO₃ Na₂N₂O₂ NaH₂PO₄ NaPO₂H₂ Na₂HPO₃ Na₂PO₃F Na₃PS₂O₂ Na₃PO₄ Na₅P₃O₁₀ Na₄P₂O₇ Na₂H₂P₂O₇ Na₃AsO₃ Na₃AsO₄ Na₂HAsO₄ NaH₂AsO₄ NaSbO₃
Others	NaAlH₄ NaAlO₂ Na₃AlF₆ NaAl(SO₄)₂ NaAuCl₄ NaSbF₆ NaAsF₆ Na₂TiF₆ NaBH₄ NaBH₃(CN) NaBO₂ Na₂B₄O₇ Na₂B₂O₉ Na₂B₈O₁₃ NaBiO₃ NaCN NaCNO NaCoO₂ NaH NaHCO₃ Na₄XeO₆ NaHXeO₄ NaMnO₄ NaOCN NaReO₄ NaSCN NaTcO₃ NaTcO₄ NaVO₃ Na₂CO₃ Na₂C₂O₄ Na₂C₃S₅ Na₂CrO₄ Na₂Cr₂O₇ Na₂Cr₃O₁₀ Na₂GeO₃ Na₂He Na₂[Fe(CO)₄] Na₂MnO₄ Na₂MoO₄ Na₃IrCl₆ Na₂PtCl₆ Na₂O(UO₃)₂ Na₂S₄O₆ Na₂SiO₃ Na₂TiO₃ Na₂U₂O₇ Na₂WO₄ Na₂Zn(OH)₄ Na₃VO₄ Na₆V₁₀O₂₈ Na₄Fe(CN)₆ Na₃Fe(CN)₆ Na₃Fe(C₂O₄)₃ Na₄SiO₄ Na₂SiF₆ Na₃[Co(NO₂)₆] NaNSi₂(CH₃)₆ Na₂PdCl₄