Nickel nitrate is the
inorganic compound Ni(NO
3)
2 or any
hydrate thereof. The
anhydrous form is not commonly encountered, thus "nickel nitrate" usually refers to nickel(II) nitrate
hexahydrate
In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was underst ...
. The formula for this species is written in two ways: Ni(NO
3)
2.6H
2O and, more descriptively
i(H2O)6NO
3)
2. The latter formula indicates that the
nickel
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow ...
(II) center is surrounded by six water molecules in this hydrated salt. In the hexahydrate, the
nitrate anions are not bonded to nickel. Also known are three other hydrates: Ni(NO
3)
2.9H
2O, Ni(NO
3)
2.4H
2O, and Ni(NO
3)
2.2H
2O. Anhydrous Ni(NO
3)
2 is also known.
It is prepared by the reaction of nickel oxide with nitric acid:
: NiO + 2 HNO
3 + 5 H
2O → Ni(NO
3)
2.6H
2O
The anhydrous nickel nitrate is typically not prepared by the heating the hydrates. Rather is generated by reaction of hydrates with
dinitrogen pentoxide
Dinitrogen pentoxide is the chemical compound with the formula , also known as nitrogen pentoxide or nitric anhydride. It is one of the binary nitrogen oxides, a family of compounds that only contain nitrogen and oxygen. It exists as colourless c ...
or of
nickel carbonyl
Nickel carbonyl (IUPAC name: tetracarbonylnickel) is a nickel(0) organometallic compound with the formula Ni(CO)4. This colorless liquid is the principal carbonyl of nickel. It is an intermediate in the Mond process for producing very high-pu ...
with
dinitrogen tetroxide:
[
: Ni(CO)4 + 2 N2O4 → Ni(NO3)2 + 2 NO + 4 CO
The hydrated nitrate is often used as a precursor to supported nickel catalysts.][
]
Structure
Nickel(II) compounds with oxygenated ligands often feature octahedral coordination geometry. Two polymorphs of the tetrahydrate Ni(NO3)2.4H2O have been crystallized. In one the monodentate nitrate ligands are trans while in the other they are cis.
Safety
Like other nitrates, nickel nitrate is oxidizing
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...
. It is also irritating to the eyes, skin and, upon inhalation of the dust, respiratory tract. It may cause skin allergy
Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derm ...
. Nickel nitrate is a carcinogen
A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive subs ...
, along with most other nickel compounds. The nickel ion is also toxic to aquatic organisms.
Uses
Nickel(II) nitrate is primarily used in electrotyping and electroplating of metallic nickel.
References
{{nitrates
Nickel compounds
Nitrates
IARC Group 1 carcinogens
Oxidizing agents