Cobalt(II) nitrate
| Cobalt(II) nitrate | |
|---|---|
-nitrate-hexahydrate-sample.jpg) | |
| Other names Cobaltous nitrate | |
| Identifiers | |
| CAS number | 10141-05-6  , 10026-22-9 (hexahydrate) |
| PubChem | 25000 |
| ChemSpider | 23369 |
| UNII | 65W79BFD5V |
| EC number | 233-402-1 |
| RTECS number | GG1109000 |
| Jmol-3D images | {{#if:[Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O|Image 1 |
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| Properties | |
| Molecular formula | 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, decomp (anhydrous) 55 °C (hexahydrate) |
| Boiling point | 100–105 °C, decomp (hexahydrate) 74 °C, decomp (hexahydrate) |
| Solubility in water | hexahydrate: 134 g/100 mL (0 °C) 103.8 g/100 mL (25 °C) soluble (anhydrous) |
| Solubility | soluble in alcohol, acetone, ethanol, ammonia (hexahydrate) |
| Structure | |
| Coordination geometry |
monoclinic (hexahydrate) |
| Hazards | |
| MSDS | Cobalt (II) Nitrate MSDS |
| EU Index | 027-009-00-2 |
| EU classification | Carc. Cat. 2 Muta. Cat. 3 Repr. Cat. 2 Toxic (T) Dangerous for the environment (N) |
| R-phrases | R49, R60, R42/43, R68, R50/53 |
| NFPA 704 |
 0
2
0
OX
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| LD50 | 434 mg/kg; rat, oral (anhydrous) 691 mg/kg; rat, oral (hexahydrate) |
| Related compounds | |
| Other anions | Cobalt(II) sulfate Cobalt(II) chloride Cobalt oxalate |
| Other cations | Iron(III) nitrate Nickel(II) nitrate |
(verify) (what is: / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | |
| Infobox references | |
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.
Preparation
Cobalt(II) nitrate is formed by the interaction of cobalt oxide, hydroxide or carbonate with nitric acid.
Composition and structures
As well as the anhydrous compound Co(NO3)2, there are several hydrates of cobalt(II) nitrate. The various degrees of hydration can be summarised by the general 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.[1] 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.[2]
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Uses
It is commonly reduced to metallic cobalt or precipitated on various substrates for Fischer-Tropsch catalysis.[3]
Production
It is derived from reacting metallic cobalt or one of its oxides, hydroxides, or carbonate with nitric acid. It is commonly used in dyes and inks.[4]
- CoCO3 + 2 HNO3 + 5 H2O → Co(NO3)2(H2O)6 + CO2
Above 55 °C, it dehydrates to the trihydrate and at higher temperatures to the monohydrate.
References
- ↑ 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.
- ↑ Prelesnik, P. V.; Gabela, F.; Ribar, B.; Krstanovic, I. (1973). Cryst. Struct. Commun. 2: 581–583.
- ↑ Ernst B, Libs S, Chaumette P, Kiennemann A. Appl. Catal. A 186 (1-2): 145-168 1999
- ↑ 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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