Cobalt (II) nitrate

Structural formula
${\displaystyle \mathrm {\ {\Biggl [}} }$ ${\displaystyle \mathrm {\ \!\ {\Biggr ]}} }$ ${\displaystyle \mathrm {\ {\Biggl [}} }$ ${\displaystyle \mathrm {\ \!\ {\Biggr ]}_{2}^{-}} }$
General
Surname	Cobalt (II) nitrate
other names	Cobalt nitrate Cobalt (II) nitrate
Molecular formula	Co (NO 3 ) 2
Brief description	red-brown hygroscopic crystals (hexahydrate)
External identifiers / databases
CAS number 10141-05-6 (anhydrous) 10026-22-9 (hexahydrate) EC number 233-402-1 ECHA InfoCard 100.030.353 PubChem 25,000 ChemSpider 23369 Wikidata Q414860
properties
Molar mass	182.94 g mol −1 (anhydrous) 291.04 g mol −1 (hexahydrate)
Physical state	firmly
density	2.49 g cm −3 (anhydrous) 1.88 g cm −3 (hexahydrate)
Melting point	55 ° C (release of crystal water)
boiling point	100–105 ° C (decomposition)
solubility	very good in water (1030 g l −1 at 25 ° C)
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 272-302-317-334-350i-341-360F-410 P: 201-210-220-280-308 + 313-370 + 378
Authorization procedure under REACH	particularly worrying : carcinogenic, toxic for reproduction ( CMR )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Cobalt nitrate is a salt of nitric acid , formed from the cobalt cation and the nitrate anion . The red-brown and hygroscopic salt is usually as hexa hydrate and forms monoclinic crystals , in water , ethanol and other organic solvents are readily soluble. Above 55 ° C, the hexahydrate changes rapidly into the trihydrate with the release of water. A monohydrate is also known; the salt, free of water of crystallization, is pale red and has a powdery consistency.

use

Sample: Cobalt (II) nitrate hexahydrate

Crucibles labeled with cobalt nitrate

It is used in classical inorganic analytical chemistry for the qualitative detection of zinc as Rinman's green (ZnCo ₂ O ₄ ) and aluminum as Thénards blue (CoAl ₂ O ₄ ) on the magnesia channel . It can also be used as a reagent in the Zwikker reaction to detect NH-acidic compounds.

It is also used to produce high-purity cobalt and is used as a colored pigment for ceramics.

Solutions are also used to permanently label porcelain crucibles .

presentation

Cobalt (II) nitrate is made by dissolving cobalt , cobalt (II) oxide or cobalt (II) carbonate in dilute nitric acid.

${\displaystyle \mathrm {CoCO_{3}+2\ HNO_{3}+6\ H_{2}O\longrightarrow Co(NO_{3})_{2}\cdot 6\ H_{2}O+H_{2}O+CO_{2}\uparrow } }$

properties

Cobalt (II) nitrate crystallizes in different crystal structures depending on the water of crystallization content, the properties of which are listed in the table below. The hexahydrate changes into the dihydrate at 106 ° C.

Lattice parameters of the various modifications of cobalt (II) nitrate
formula	Crystal system	Space group	a [ Å ]	b [Å]	c [Å]	β	Z
Co (NO 3 ) 2  · 6H 2 O	monoclinic	C 2 / c (No. 15)	14.29	6.14	12.66	112.79 °	4th
Co (NO 3 ) 2  · 2 H 2 O	monoclinic	P 2 1 / n (No. 14, position 2)	6,019	8,629	5.729	92.65 °	2
Co (NO 3 ) 2	trigonal	R 3 (No. 148)	10.50	-	12.84		12

toxicology

Cobalt (II) nitrate is carcinogenic and mutagenic and is also suspected of being teratogenic.

See also

Cobalt (III) nitrate

Individual evidence

1. ↑ ^{a b c d e f g} Entry on cobalt (II) nitrate in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .
2. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Inorganic Compounds, pp. 4-60.
3. ↑ Entry on cobalt dinitrate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
4. ↑ Entry in the SVHC list of the European Chemicals Agency , accessed on July 17, 2014.
5. ↑ ^{a b} B. Ribár, N. Milinski, R. Herak, I. Krstanovič, S. Djurič: "The crystal structure of cobalt nitrate dihydrate, Co (NO ₃ ) ₂  · 2 H ₂ O" in Zeitschrift für Kristallographie 1976 144 (1-6), pp. 133-138. doi : 10.1524 / zkri.1976.144.1-6.133
6. ^ Jean D'Ans, Ellen Lax: Pocket book for chemists and physicists. 3. Elements, inorganic compounds and materials, minerals, Volume 3. 4. Edition, Springer, 1997, ISBN 978-3-540-60035-0 , p. 386 ( limited preview in the Google book search).
7. ↑ GA Tikhomirov, KO Znameskov, IV Morozov, E. Kemnitz, SI Troyanov: Anhydrous nitrates and nitrosonium nitratometallates of manganese and cobalt, M (NO ₃ ) ₂ , NO (Mn (NO ₃ ) ₃ ), and (NO) ₂ ( Co (NO ₃ ) ₄ ): synthesis and crystal structure. In: Journal for inorganic and general chemistry , 628, 2002, pp. 269-273, doi : 10.1002 / 1521-3749 (200201) 628: 1 <269 :: AID-ZAAC269> 3.0.CO; 2-P .