Potassium diphosphate

Structural formula
General
Surname	Potassium diphosphate
other names	Potassium pyrophosphate; Tetrapotassium pyrophosphate;
Molecular formula	K 4 P 2 O 7
Brief description	white solid
External identifiers / databases
EC number	230-785-7
ECHA InfoCard	100,027,986
PubChem	23740
Wikidata	Q2575439
properties
Molar mass	330.34 g mol −1
Physical state	firmly
density	2.61 g cm −3
Melting point	1090 ° C
solubility	very light in water (1870 g l −1 at 25 ° C); insoluble in ethanol;
safety instructions
GHS labeling of hazardous substances Caution
H and P phrases	H: 319
	P: 305 + 351 + 338
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Potassium diphosphate is an inorganic chemical compound of potassium from the group of diphosphates which is normally present as a trihydrate.

Extraction and presentation

Potassium diphosphate can be obtained by dehydrating dipotassium hydrogen phosphate at 350 - 400 ° C.

{\ displaystyle \ mathrm {2 \ K_ {2} HPO_ {4} \ longrightarrow K_ {4} P_ {2} O_ {7} + H_ {2} O}}

It is also possible to obtain it by reacting potassium carbonate with phosphorus pentoxide .

{\ displaystyle \ mathrm {2 \ K_ {2} CO_ {3} + P_ {2} O_ {5} \ longrightarrow K_ {4} P_ {2} O_ {7} +2 \ CO_ {2}}}

properties

Potassium diphosphate is a white, hygroscopic solid that is very easily soluble in water. The trihydrate converts to monohydrate at 180 ° C and to anhydrate at 330 ° C.

use

Potassium diphosphate is used in textile auxiliaries to prevent hardness deposits, as a soap additive, for the cathodic deposition of tin or tin-gold alloys, for hydrogen peroxide stabilization, for clay cleaning and in oil drilling.

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g Entry on potassium diphosphate in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .
^ ^A ^b Dale L. Perry: Handbook of Inorganic Compounds . CRC Press, 1995, ISBN 978-0-8493-8671-8 , pp. 315 ( limited preview in Google Book search).
↑ ^a ^b Entry on potassium phosphates. In: Römpp Online . Georg Thieme Verlag, accessed on January 17, 2015.
^ Arthur DF Toy: The Chemistry of Phosphorus: Pergamon Texts in Inorganic Chemistry . Elsevier, 2013, ISBN 978-1-4831-4741-3 , pp. 513 ( limited preview in Google Book search).
↑ Govindhan Dhanaraj, Kullaiah Byrappa, Vishwanath Prasad, Michael Dudley: Springer Handbook of Crystal Growth . Springer Science & Business Media, 2010, ISBN 978-3-540-74761-1 , p. 740 ( limited preview in Google Book search).

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g Entry on potassium diphosphate in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .

[Dale_L._Perry-2] A ^b Dale L. Perry: Handbook of Inorganic Compounds . CRC Press, 1995, ISBN 978-0-8493-8671-8 , pp. 315 ( limited preview in Google Book search).

[RömppOnline-3] Entry on potassium phosphates. In: Römpp Online . Georg Thieme Verlag, accessed on January 17, 2015.

[Arthur_D._F._Toy-4] Arthur DF Toy: The Chemistry of Phosphorus: Pergamon Texts in Inorganic Chemistry . Elsevier, 2013, ISBN 978-1-4831-4741-3 , pp. 513 ( limited preview in Google Book search).

[Govindhan_Dhanaraj,_Kullaiah_Byrappa,_Vishwanath_Prasad,_Michael_Dudley-5] Govindhan Dhanaraj, Kullaiah Byrappa, Vishwanath Prasad, Michael Dudley: Springer Handbook of Crystal Growth . Springer Science & Business Media, 2010, ISBN 978-3-540-74761-1 , p. 740 ( limited preview in Google Book search).