Calcium nitrite

Structural formula
General
Surname	Calcium nitrite
other names	Calcium nitrite
Molecular formula	Ca (NO 2 ) 2
Brief description	white to yellow solid
External identifiers / databases
EC number	237-424-2
ECHA InfoCard	100.034.008
PubChem	159695
Wikidata	Q2749498
properties
Molar mass	132.09 g mol −1
Physical state	firmly
density	2.23 g cm −3
Melting point	392 ° C (decomposition)
solubility	soluble in water
Refractive index	1.3946 (20 ° C)
safety instructions
GHS labeling of hazardous substances	no GHS pictograms
	no GHS pictograms
H and P phrases	H: no H-phrases
	P: no P-phrases
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Calcium nitrite is an inorganic chemical compound of calcium from the group of nitrites .

Extraction and presentation

Calcium nitrite can be obtained by reacting nitric oxide and a mixture of calcium ferrate and calcium nitrate .

It can also be represented by the reaction of sodium nitrite and calcium chloride or, industrially, by the reaction of calcium hydroxide with nitrogen oxides.

{\ displaystyle {\ ce {2 NaNO2 + CaCl2 -> Ca (NO2) 2 + 2 NaCl}}}

{\ displaystyle {\ ce {2 Ca (OH) 2 + 4 NO2 -> Ca (NO2) 2 + Ca (NO3) 2 + 2 H2O}}}

properties

Calcium nitrite is a hygroscopic white to yellow solid that is soluble in water. It is sparingly soluble in ethanol . It breaks down at 392 ° C to form nitrogen oxides and calcium oxide. The tetrahydrate loses two parts of the water of crystallization at about 80 ° C and one at 105 ° C to form the monohydrate. At around 155 ° C, it turns into anhydrate. This is unstable when heated further and oxidizes to calcium nitrate in air above 220 ° C. Anhydrous calcium nitrite is unstable and slowly oxidizes to nitrate in air.

{\ displaystyle {\ ce {Ca (NO2) 2 + O2 -> Ca (NO3) 2}}}

use

Calcium nitrite is used in lubricants as a corrosion protection agent. It is also used in concrete mixes as an anti-freeze and to improve the properties of the concrete. It also serves as a mild reducing agent .

Individual evidence

↑ ^a ^b ^c ^d ^e William M. Haynes: CRC Handbook of Chemistry and Physics . CRC Press, 2016, ISBN 978-1-4987-5429-3 , pp. 54 ( limited preview in Google Book search).
↑ ^a ^b ^c ^d ^e data sheet Calcium nitrite solution, 30 wt.% In H ₂ O from Sigma-Aldrich , accessed on February 21, 2019 ( PDF ).
^ ^A ^b Dale L. Perry: Handbook of Inorganic Compounds . CRC Press, 2016, ISBN 978-1-4398-1462-8 , pp. 93 ( limited preview in Google Book search).
↑ ^a ^b ^c Richard C. Ropp: Encyclopedia of the Alkaline Earth Compounds . Newnes, 2012, ISBN 0-444-59553-8 , pp. 199 ( limited preview in Google Book search).
↑ AM Paillere: Application of Admixtures in Concrete . CRC Press, 1994, ISBN 978-0-419-19960-1 , pp. 92 ( limited preview in Google Book search).

[William_M._Haynes-1] William M. Haynes: CRC Handbook of Chemistry and Physics . CRC Press, 2016, ISBN 978-1-4987-5429-3 , pp. 54 ( limited preview in Google Book search).

[Sigma-2] ↑ ^a ^b ^c ^d ^e data sheet Calcium nitrite solution, 30 wt.% In H ₂ O from Sigma-Aldrich , accessed on February 21, 2019 ( PDF ).

[Dale_L._Perry-3] A ^b Dale L. Perry: Handbook of Inorganic Compounds . CRC Press, 2016, ISBN 978-1-4398-1462-8 , pp. 93 ( limited preview in Google Book search).

[Richard_C._Ropp-4] Richard C. Ropp: Encyclopedia of the Alkaline Earth Compounds . Newnes, 2012, ISBN 0-444-59553-8 , pp. 199 ( limited preview in Google Book search).

[A.M._Paillere-5] AM Paillere: Application of Admixtures in Concrete . CRC Press, 1994, ISBN 978-0-419-19960-1 , pp. 92 ( limited preview in Google Book search).