Cobalt nitrate is the inorganic compound with the formula Co(NO3)2.xH2O. It is cobalt(II)'s 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.[2]
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Names | |
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Other names
Cobaltous nitrate
Nitric acid, cobalt(2+) salt | |
Identifiers | |
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3D model (JSmol)
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ChEBI |
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ChemSpider |
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ECHA InfoCard | 100.030.353 |
EC Number |
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PubChem CID
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RTECS number |
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UNII |
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UN number | 1477 |
CompTox Dashboard (EPA)
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Properties | |
Co(NO3)2(H2O)6 | |
Molar mass | 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) |
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), methanol 2.1 g/100 mL |
Structure | |
monoclinic (hexahydrate) | |
Hazards | |
GHS labelling: | |
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Danger | |
H317, H334, H341, H350, H360, H410 | |
P201, P202, P261, P272, P273, P280, P281, P285, P302+P352, P304+P341, P308+P313, P321, P333+P313, P342+P311, P363, P391, P405, P501 | |
NFPA 704 (fire diamond) | |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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434 mg/kg; rat, oral (anhydrous) 691 mg/kg; rat, oral (hexahydrate) |
Safety data sheet (SDS) | Cobalt (II) Nitrate MSDS |
Related compounds | |
Other anions
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Cobalt(II) sulfate Cobalt(II) chloride Cobalt oxalate |
Other cations
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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).
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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.[4] 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.[5] Above 55 °C, the hexahydrate converts to the trihydrate and at higher temperatures to the monohydrate.[2]
Co(NO3)2 | Co(NO3)2·2H2O | Co(NO3)2·4H2O | Co(NO3)2·6H2O |
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.[6] It is used in the preparation of dyes and inks.[7]
Cobalt(II) nitrate is a common starting material for the preparation of coordination complexes such as cobaloximes,[8] carbonatotetraamminecobalt(III),[9] and others.[10]
The hexahydrate is prepared treating metallic cobalt or one of its oxides, hydroxides, or carbonate with nitric acid:
HNO3 | He | |||||||||||||||||
LiNO3 | Be(NO3)2 | B(NO3)−4 | RONO2 | NO−3 NH4NO3 |
HOONO2 | 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)2 Fe(NO3)3 |
Co(NO3)2 Co(NO3)3 |
Ni(NO3)2 | CuNO3 Cu(NO3)2 |
Zn(NO3)2 | Ga(NO3)3 | Ge | As | Se | BrNO3 | Kr | |
RbNO3 | Sr(NO3)2 | Y(NO3)3 | Zr(NO3)4 | NbO(NO3)3 | MoO2(NO3)2 | Tc | Ru(NO3)3 | Rh(NO3)3 | Pd(NO3)2 Pd(NO3)4 |
AgNO3 Ag(NO3)2 |
Cd(NO3)2 | In(NO3)3 | Sn(NO3)4 | Sb(NO3)3 | Te | INO3 | Xe(NO3)2 | |
CsNO3 | Ba(NO3)2 | Lu(NO3)3 | Hf(NO3)4 | TaO(NO3)3 | W | Re | Os | Ir | Pt(NO3)2 Pt(NO3)4 |
Au(NO3)3 | Hg2(NO3)2 Hg(NO3)2 |
TlNO3 Tl(NO3)3 |
Pb(NO3)2 | Bi(NO3)3 BiO(NO3) |
Po(NO3)4 | At | Rn | |
FrNO3 | Ra(NO3)2 | Lr | Rf | Db | Sg | Bh | Hs | Mt | Ds | Rg | Cn | Nh | Fl | Mc | Lv | Ts | Og | |
↓ | ||||||||||||||||||
La(NO3)3 | Ce(NO3)3 Ce(NO3)4 |
Pr(NO3)3 | Nd(NO3)3 | Pm(NO3)3 | Sm(NO3)3 | Eu(NO3)3 | Gd(NO3)3 | Tb(NO3)3 | Dy(NO3)3 | Ho(NO3)3 | Er(NO3)3 | Tm(NO3)3 | Yb(NO3)3 | |||||
Ac(NO3)3 | Th(NO3)4 | PaO2(NO3)3 | UO2(NO3)2 | Np(NO3)4 | Pu(NO3)4 | Am(NO3)3 | Cm(NO3)3 | Bk(NO3)3 | Cf | Es | Fm | Md | No |