Sodium diphosphate

Structural formula
General
Surname	Sodium diphosphate
other names	Sodium pyrophosphate; Sodium diphosphate; Tetrasodium pyrophosphate; Tetrasodium diphosphate; Diphosphate; E 450c; TETRASODIUM PYROPHOSPHATE ( INCI ) ;
Molecular formula	Na 4 P 2 O 7
Brief description	white odorless solid
External identifiers / databases
EC number	231-767-1
ECHA InfoCard	100,028,880
PubChem	24403
ChemSpider	22813
Wikidata	Q418504
properties
Molar mass	265.90 g mol −1
Physical state	firmly
density	2.53 g cm −3 (anhydrous); 1.82–1.84 g cm −3 (decahydrate);
Melting point	990 ° C (anhydrous); Dehydration at 94 ° C (decahydrate);
solubility	slightly soluble in water (60 g l −1 at 20 ° C)
safety instructions
H and P phrases	H: 302-318
	P: 264-270-301 + 312-330-280
MAK	Switzerland: 5 mg m −3 (measured as inhalable dust )
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Sodium diphosphate or sodium pyrophosphate is a colorless sodium salt of diphosphoric acid . It belongs to the diphosphates and has the empirical formula Na ₄ P ₂ O ₇ . The name diphosphate is occasionally used in place of tetrasodium diphosphate . Diphosphates are also parts of organic compounds such as adenosine diphosphate . As a food additive , tetrasodium diphosphate is known as E 450c.

presentation

The pyrophosphate can be obtained by heating disodium hydrogen phosphate at 500 ° C for several hours :

{\ displaystyle {\ ce {2 Na2HPO4 -> Na4P2O7 + H2O}}}

use

In detergents and dishwashing detergents and toothpaste as an emulsifier for fats and oils and water softeners , in baking powder, in cheese preparation. It is also used to stabilize hydrogen peroxide .

The decahydrate is used as a dispersant for a sludge analysis according to DIN EN ISO 17892-4.

Individual evidence

↑ Entry on TETRASODIUM PYROPHOSPHATE in the CosIng database of the EU Commission, accessed on April 17, 2020.
↑ ^a ^b ^c ^d ^e ^f ^g ^h Entry on sodium pyrophosphate in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
↑ Swiss Accident Insurance Fund (Suva): Limit Values - Current MAK and BAT values (search for 7722-88-5 or tetrasodium pyrophosphate ), accessed on March 4, 2020.
^ RN Bell: Sodium pyrophosphates (Sodium diphosphates) . In: Ludwig F. Audrieth (Ed.): Inorganic Syntheses . tape 3 . McGraw-Hill, Inc., 1950, pp. 98-101 (English).

[CosIng-1] Entry on TETRASODIUM PYROPHOSPHATE in the CosIng database of the EU Commission, accessed on April 17, 2020.

[GESTIS-2] ↑ ^a ^b ^c ^d ^e ^f ^g ^h Entry on sodium pyrophosphate in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .

[3] Swiss Accident Insurance Fund (Suva): Limit Values - Current MAK and BAT values (search for 7722-88-5 or tetrasodium pyrophosphate ), accessed on March 4, 2020.

[IS3-4] RN Bell: Sodium pyrophosphates (Sodium diphosphates) . In: Ludwig F. Audrieth (Ed.): Inorganic Syntheses . tape 3 . McGraw-Hill, Inc., 1950, pp. 98-101 (English).