Sodium pyrosulfate[ 1]
Names
IUPAC name
Disodium disulfate
Other names
Sodium pyrosulphate; Disulfuric acid disodium salt, disodium disulfate; Sodium metabisulfate
Identifiers
ChEMBL
ChemSpider
ECHA InfoCard
100.034.190
EC Number
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
[Na+].[Na+].[O-]S(=O)(=O)OS(=O)(=O)[O-]
Properties
Na2 S2 O7
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)
hydrolyses[ 2]
Except where otherwise noted, data are given for materials in their
standard state (at 25 °C [77 °F], 100 kPa).
Chemical compound
Sodium pyrosulfate is an inorganic compound with the chemical formula of Na2 S2 O7 .[ 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 heating sodium bisulfate to 280 °C (536 °F) [ 4] [ 5]
2 NaHSO4 → Na2 S2 O7 + H2 O
Temperatures above 460 °C further decompose the compound, producing sodium sulfate and sulfur trioxide :
Na2 S2 O7 → Na2 SO4 + 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]
See also
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 .
Inorganic
Halides Chalcogenides Pnictogenides Oxyhalides Oxychalcogenides Oxypnictogenides Others
Organic