Sodium pyrosulfate

Sodium pyrosulfate is an inorganic compound with the chemical formula of Na₂S₂O₇.[1] It is a colorless salt.[3]

Sodium pyrosulfate[1]

Names
IUPAC name Disodium disulfate
Other names Sodium pyrosulphate; Disulfuric acid disodium salt, disodium disulfate
Identifiers
CAS Number	13870-29-6
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL111016
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/cm^3
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).
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Infobox references

Preparation

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

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.[5][6]

See also

• Pyrosulfate
• Potassium bisulfate
• Potassium pyrosulfate

References

1. Olsen, J. C., ed. (1934). Van Nostrand's Chemical Annual. London: Chapman and Hall.
2. Heinz K. Hofmeister; John R. Van Wazer (1962). "Hydrolysis of Sodium Pyrosulfate". Inorganic Chemistry. ACS. 1 (4): 811–812. doi:10.1021/ic50004a019.
3. Helmold Plessen (2000). "Sodium Sulfates". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a24_355. ISBN 978-3527306732.
4. Noyes, William (1913). A Textbook of Chemistry. New York: Henry Holt and Company. p. 186. Retrieved 13 January 2016.
5. 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.
6. 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.