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Cobalt(II) nitrate

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Cobalt(II) nitrate
Cobalt (II) Nitrate Hexahydrate Sample
Names
Other names
Caviar, Cobaltous nitrate
Nitric acid, cobalt(2+) salt
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.030.353 Edit this at Wikidata
EC Number
  • 233-402-1
RTECS number
  • GG1109000
UNII
  • InChI=1S/Co.2NO3/c;2*2-1(3)4/q+2;2*-1 checkY
    Key: UFMZWBIQTDUYBN-UHFFFAOYSA-N checkY
  • InChI=1/Co.2NO3/c;2*2-1(3)4/q+2;2*-1
    Key: UFMZWBIQTDUYBN-UHFFFAOYAS
  • [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O
Properties
Co(NO3)2
Molar mass 182.943 g/mol (anhydrous)
291.03 g/mol (hexahydrate)
Appearance pale red powder (anhydrous)
red crystalline (hexahydrate)
Odor odorless (hexahydrate)
Density 2.49 g/cm3 (anhydrous)
1.87 g/cm3 (hexahydrate)
Melting point 100 °C (212 °F; 373 K) decomposes (anhydrous)
55 °C (hexahydrate)
Boiling point 100 to 105 °C (212 to 221 °F; 373 to 378 K) decomposes (hexahydrate)
74 °C, decomposes (hexahydrate)
anhydrous:[1] 84.03 g/100 mL (0 °C)
334.9 g/100 mL (90 °C)
soluble (anhydrous)
Solubility soluble in alcohol, acetone, ethanol, ammonia (hexahydrate)
Structure
monoclinic (hexahydrate)
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazard OX: Oxidizer. E.g. potassium perchlorate
2
0
0
OX
Lethal dose or concentration (LD, LC):
434 mg/kg; rat, oral (anhydrous)
691 mg/kg; rat, oral (hexahydrate)
Safety data sheet (SDS) Cobalt (II) Nitrate MSDS
Related compounds
Other anions
 Cobalt(II) sulfate
Cobalt(II) chloride
Cobalt oxalate
Other cations
 Iron(III) nitrate
Nickel(II) nitrate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Cobalt Nitrate is the inorganic cobalt(II) salt of nitric acid, often with various amounts of water. It is more commonly found as a hexahydrate, Co(NO3)2·6H2O, which is a red-brown deliquescent salt that is soluble in water and other polar solvents.[2]

Composition and structures

As well as the anhydrous compound Co(NO3)2, several hydrates of cobalt(II) nitrate exist. These hydrates have the chemical formula Co(NO3)2·nH2O, where n = 0, 2, 4, 6.

Anhydrous cobalt(II) nitrate adopts a three-dimensional polymeric network structure, with each cobalt(II) atom approximately octahedrally coordinated by six oxygen atoms, each from a different nitrate ion. Each nitrate ion coordinates to three cobalts.[3] The dihydrate is a two-dimensional polymer, with nitrate bridges between Co(II) centres and hydrogen bonding holding the layers together. The tetrahydrate consists of discrete, octahedral [(H2O)4Co(NO3)2] molecules. The hexahydrate is better described as hexaaquacobalt(II) nitrate, [Co(OH2)6][NO3]2, as it consists of discrete [Co(OH2)6]2+ and [NO3]− ions.[4] Above 55 °C, the hexahydrate converts to the trihydrate and at higher temperatures to the monohydrate.[2]

Uses

It is commonly reduced to metallic high purity cobalt.[2] It can be absorbed on to various catalyst supports for use in Fischer-Tropsch catalysis.[5] It is used in the preparation of dyes and inks.[6]

Production

The hexahydrate is prepared treating metallic cobalt or one of its oxides, hydroxides, or carbonate with nitric acid:

Co + 4 HNO3 + 4 H2O → Co(H2O)6(NO3)2 + 2 NO2
CoO + 2 HNO3 + 5 H2O → Co(H2O)6(NO3)2
CoCO3 + 2 HNO3 + 5 H2O → Co(H2O)6(NO3)2 + CO2
Co(NO3)2
Co(NO3)2·2H2O
Co(NO3)2·4H2O
Co(NO3)2·6H2O

References

  1. ^ Perrys' Chem Eng Handbook, 7th Ed
  2. ^ a b c John Dallas Donaldson, Detmar Beyersmann, "Cobalt and Cobalt Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi:10.1002/14356007.a07_281.pub2
  3. ^ Tikhomirov, G. A.; Znamenkov, K. O.; Morozov, I. V.; Kemnitz, E.; Troyanov, S. I. (2002). "Anhydrous Nitrates and Nitrosonium Nitratometallates of Manganese and Cobalt, M(NO3)2, NO[Mn(NO3)3], and (NO)2[Co(NO3)4]: Synthesis and Crystal Structure". Z. anorg. allg. Chem. 628 (1): 269–273. doi:10.1002/1521-3749(200201)628:1<269::AID-ZAAC269>3.0.CO;2-P.
  4. ^ Prelesnik, P. V.; Gabela, F.; Ribar, B.; Krstanovic, I. (1973). "Hexaaquacobalt(II) nitrate". Cryst. Struct. Commun. 2 (4): 581–583.
  5. ^ Ernst B, Libs S, Chaumette P, Kiennemann A. Appl. Catal. A 186 (1-2): 145-168 1999
  6. ^ Lewis, Richard J., Sr. (2002). Hawley's Condensed Chemical Dictionary (14th Edition). John Wiley & Sons. http://www.knovel.com/knovel2/Toc.jsp?BookID=704&VerticalID=0
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