Cobalt(II) nitrate

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Cobalt(II) nitrate
Cobalt (II) Nitrate Hexahydrate Sample
Other names
Cobaltous nitrate
Nitric acid, cobalt(2+) salt
3D model (JSmol)
ECHA InfoCard 100.030.353
EC Number 233-402-1
RTECS number GG1109000
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 (anhydrous)[citation needed]
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)
monoclinic (hexahydrate)
Safety data sheet Cobalt (II) Nitrate MSDS
Carc. Cat. 2
Muta. Cat. 3
Repr. Cat. 2
Toxic (T)
Dangerous for the environment (N)
R-phrases (outdated) R49, R60, R42/43, R68, R50/53
S-phrases (outdated) S53, S45, S60, S61
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazard OX: Oxidizer. E.g., potassium perchlorateNFPA 704 four-colored diamond
Lethal dose or concentration (LD, LC):
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
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
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.[2]

Composition and structures[edit]

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]


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]


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
Cobalt(II)-nitrate-xtal-2002-CM-3D-SF.png Cobalt(II)-nitrate-dihydrate-xtal-1976-CM-3D-balls.png Cobalt(II)-nitrate-tetrahydrate-xtal-1975-CM-3D-balls.png Hexaaquacobalt(II)-nitrate-xtal-1973-unit-cell-CM-3D-balls.png


  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.
Salts and covalent derivatives of the Nitrate ion
LiNO3 Be(NO3)2 B(NO3)4 C N O FNO3 Ne
NaNO3 Mg(NO3)2 Al(NO3)3 Si P S ClONO2 Ar
KNO3 Ca(NO3)2 Sc(NO3)3 Ti(NO3)4 VO(NO3)3 Cr(NO3)3 Mn(NO3)2 Fe(NO3)3,
Ni(NO3)2 Cu(NO3)2 Zn(NO3)2 Ga(NO3)3 Ge As Se Br Kr
RbNO3 Sr(NO3)2 Y Zr(NO3)4 Nb Mo Tc Ru Rh Pd(NO3)2 AgNO3 Cd(NO3)2 In Sn Sb(NO3)3 Te I Xe(NO3)2
CsNO3 Ba(NO3)2   Hf Ta W Re Os Ir Pt Au Hg2(NO3)2,
Pb(NO3)2 Bi(NO3)3
Po At Rn
FrNO3 Ra(NO3)2   Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
La(NO3)3 Ce(NO3)3,
Pr Nd Pm Sm Eu Gd(NO3)3 Tb Dy Ho Er Tm Yb Lu
Ac(NO3)3 Th(NO3)4 Pa UO2(NO3)2 Np Pu Am Cm Bk Cf Es Fm Md No Lr