cobalt(II) nitrate
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 476999100
| Name = Cobalt(II) nitrate
| ImageFile1 = Cobalt(II) Nitrate.jpg
| ImageName1 = Cobalt (II) Nitrate Hexahydrate Sample
| ImageCaption1 = Hexahydrate
| OtherNames = Cobaltous nitrate
Nitric acid, cobalt(2+) salt
| Section1 = {{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 23369
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 65W79BFD5V
| InChI = 1/Co.2NO3/c;2*2-1(3)4/q+2;2*-1
| SMILES = [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O
| InChIKey = UFMZWBIQTDUYBN-UHFFFAOYAS
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/Co.2NO3/c;2*2-1(3)4/q+2;2*-1
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = UFMZWBIQTDUYBN-UHFFFAOYSA-N
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 10026-22-9
| CASNo_Comment = hexahydrate
| CASNo1 = 10141-05-6
| CASNo1_Comment = anhydrous
| CASNo2 = 7697-37-2
| CASNo2_Comment = dihydrate
| PubChem = 25000
| ChEBI_Ref = {{ebicite|changed|EBI}}
| ChEBI = 86209
| EINECS = 233-402-1
| RTECS = GG1109000
| UNNumber = 1477
}}
| Section2 = {{Chembox Properties
| Formula = Co(NO3)2(H2O)6
| MolarMass = 291.03 g/mol (hexahydrate)
182.943 g/mol (anhydrous)
| Appearance = pale red powder (anhydrous)
red crystalline (hexahydrate)
| Odor = odorless
| Density = 1.87 g/cm3 (hexahydrate)
2.49 g/cm3 (anhydrous)
| Solubility = anhydrous:Perrys' Chem Eng Handbook, 7th Ed 84.03 g/100 mL (0 °C)
334.9 g/100 mL (90 °C)
soluble (anhydrous)
| SolubleOther = soluble in alcohol, acetone, ethanol, ammonia (hexahydrate), methanol 2.1 g/100 mL
| MeltingPtC = 100
| MeltingPt_notes = decomposes (anhydrous)
55 °C (hexahydrate)
| BoilingPtC = 100 to 105
| BoilingPt_notes = decomposes (anhydrous){{citation needed|date=February 2017}}
74 °C, decomposes (hexahydrate)
}}
| Section3 = {{Chembox Structure
| MolShape =
| Coordination = monoclinic (hexahydrate)
| CrystalStruct =
| Dipole =
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| Section7 = {{Chembox Hazards
| ExternalSDS = [http://hazard.com/msds/mf/baker/baker/files/c4939.htm Cobalt (II) Nitrate MSDS]
| GHSPictograms = {{GHS07}}{{GHS09}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|317|334|341|350|360|410}}
| PPhrases = {{P-phrases|201|202|261|272|273|280|281|285|302+352|304+341|308+313|321|333+313|342+311|363|391|405|501}}
| NFPA-H = 2
| NFPA-F = 0
| NFPA-R = 0
| NFPA-S = OX
| LD50 = 434 mg/kg; rat, oral (anhydrous)
691 mg/kg; rat, oral (hexahydrate)
}}
| Section8 = {{Chembox Related
| OtherAnions = Cobalt(II) sulfate
Cobalt(II) chloride
Cobalt oxalate
| OtherCations = Iron(III) nitrate
Nickel(II) nitrate
| OtherCompounds =
}}
}}
Cobalt nitrate is the inorganic compound with the formula Co(NO3)2.xH2O. It is a cobalt(II) salt. The most common form is the hexahydrate Co(NO3)2·6H2O, which is a red-brown deliquescent salt that is soluble in water and other polar solvents.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}}
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.{{ cite journal | first1 = G. A. | last1 = Tikhomirov | first2 = K. O. | last2 = Znamenkov | first3 = I. V. | last3 = Morozov | first4 = E. | last4 = Kemnitz | first5 = S. I. | last5 = Troyanov | journal = Z. anorg. allg. Chem. | year = 2002 | volume = 628 | issue = 1 | pages = 269–273 | title = 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 | doi = 10.1002/1521-3749(200201)628:1<269::AID-ZAAC269>3.0.CO;2-P | doi-access = free }} The dihydrate is a two-dimensional polymer, with nitrate bridges between Co(II) centres and hydrogen bonding holding the layers together.{{cite journal |doi=10.1524/zkri.1976.144.1-6.133| title=The Crystal Structure of Cobalt Nitrate Dihydrate, Co(NO3)2·2H2O | year=1976 | last1=Ribár | first1=B. | last2=Milinski | first2=N. | last3=Herak | first3=R. | last4=Krstanovič | first4=I. | last5=Djurič | first5=S. | journal=Zeitschrift für Kristallographie | volume=144 | issue=1–6 | pages=133–138 | bibcode=1976ZK....144..133R }} 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.{{ cite journal | journal = Cryst. Struct. Commun. | first1 = P. V. | last1 = Prelesnik | first2 = F. | last2 = Gabela | first3 = B. | last3 = Ribar | first4 = I. | last4 = Krstanovic | volume = 2 | issue = 4 | year = 1973| pages = 581–583 | title = Hexaaquacobalt(II) nitrate}} Above 55 °C, the hexahydrate converts to the trihydrate and at higher temperatures to the monohydrate.
Cobalt(II)-nitrate-xtal-2002-CM-3D-SF.png|Co(NO3)2
Cobalt(II)-nitrate-dihydrate-xtal-1976-CM-3D-balls.png|Co(NO3)2·2H2O
Cobalt(II)-nitrate-tetrahydrate-xtal-1975-CM-3D-balls.png|Co(NO3)2·4H2O
Hexaaquacobalt(II)-nitrate-xtal-1973-unit-cell-CM-3D-balls.png|Co(NO3)2·6H2O
Uses and reactions
It is commonly reduced to metallic high purity cobalt. It can be absorbed on to various catalyst supports for use in Fischer–Tropsch catalysis.Ernst B, Libs S, Chaumette P, Kiennemann A. Appl. Catal. A 186 (1-2): 145-168 1999 It is used in the preparation of dyes and inks.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
Cobalt(II) nitrate is a common starting material for the preparation of coordination complexes such as cobaloximes,{{cite book |doi=10.1002/9780470132425.ch12| title=Bis(Dimethylglyoximato)Cobalt Complexes: ("Cobaloximes") | series=Inorganic Syntheses | year=1968 | last1=Schrauzer | first1=G. N. | pages=61–70| isbn=9780470132425 }} carbonatotetraamminecobalt(III),{{cite journal |doi=10.1002/9780470132371.ch55|title=Carbonatotetramminecobalt(III) Nitrate |journal=Inorganic Syntheses |volume=6|year=1960 |last1=Schlessinger |first1=G.| pages=173–175 |isbn=9780470132371 }} and others.{{cite book |doi=10.1002/9780470132456.ch15| chapter=Bis(ethylenediamine)sulfito Complexes of Cobalt(III) | series=Inorganic Syntheses | year=1973 | last1=Hargens | first1=Robert D. | last2=Min | first2=Woonza | last3=Henney | first3=Robert C. | title=Inorganic Syntheses | pages=77–81 | isbn=9780470132456 }}
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
References
{{reflist}}
{{Cobalt compounds}}
{{nitrates}}