Sodium pyrosulfate

Sodium pyrosulfate^[1]

Names
IUPAC name Disodium disulfate
Other names Sodium pyrosulphate; Disulfuric acid disodium salt.
Identifiers
CAS Number	13870-29-6
ChEMBL	ChEMBL111016
Jmol interactive 3D	Image
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	Soluble
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

Sodium pyrosulfate, or Disodium disulfate, is an inorganic compound with the chemical formula is Na₂S₂O₇.^[1]

Preparation

Sodium pyrosulfate is obtained by the dehydration of sodium bisulfate:^[2]

2 NaHSO₄ → Na₂S₂O₇ + H₂O

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

Na₂S₂O₇ → Na₂SO₄ + SO₃

Applications

Sodium pyrosulfate is used in analytical chemistry; samples are fused with sodium pyrosulfate to ensure complete dissolution prior to a quantitative analysis.^[3][4]

See also

• Pyrosulfate
• Potassium bisulfate
• Potassium pyrosulfate

References

1. Olsen, J. C., ed. (1934). Van Nostrand's Chemical Annual. London: Chapman and Hall.
2. Noyes, William (1913). A Textbook of Chemistry. New York: Henry Holt and Company. p. 186. Retrieved 13 January 2016.
3. 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.
4. 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. doi:10.2136/sssaj1965.03615995002900020015x.