Cadmium nitrate describes any of the related members of a family of
inorganic compounds with the general
formula Cd(NO3)2.\mathitH2O, the most commonly encountered form being the
tetrahydrate
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 anhydrous form is volatile, but the others are colourless crystalline solids that are
deliquescent
Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance' ...
, tending to absorb enough moisture from the air to form an aqueous solution. Like other cadmium compounds, cadmium nitrate is known to be
carcinogenic
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 ...
.
Uses
Cadmium nitrate is used for coloring
glass
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling ( quenching ...
and
porcelain
Porcelain () is a ceramic material made by heating substances, generally including materials such as kaolinite, in a kiln to temperatures between . The strength and translucence of porcelain, relative to other types of pottery, arises main ...
[Karl-Heinz Schulte-Schrepping, Magnus Piscator "Cadmium and Cadmium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2007 Wiley-VCH, Weinheim. .] and as a
flash powder
Flash powder is a pyrotechnic composition, a mixture of oxidizer and metallic fuel, which burns quickly and produces a loud noise regardless of confinement. It is widely used in theatrical pyrotechnics and fireworks (namely salutes, e.g., cherry ...
in
photography
Photography is the art, application, and practice of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employe ...
.
Preparation
Cadmium nitrate is prepared by dissolving cadmium metal or its oxide, hydroxide, or carbonate, in
nitric acid
Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitri ...
followed by
crystallization:
: CdO + 2HNO
3 → Cd(NO
3)
2 + H
2O
: CdCO
3 + 2 HNO
3 → Cd(NO
3)
2 + CO
2 + H
2O
: Cd + 4 HNO
3 → 2 NO
2 + 2 H
2O + Cd(NO
3)
2
Reactions
Thermal dissociation at elevated temperatures produces
cadmium oxide
Cadmium oxide is an inorganic compound with the formula CdO. It is one of the main precursors to other cadmium compounds. It crystallizes in a cubic rocksalt lattice like sodium chloride, with octahedral cation and anion centers. It occurs natura ...
and oxides of nitrogen. When
hydrogen sulfide is passed through an acidified solution of cadmium nitrate, yellow
cadmium sulfide
Cadmium sulfide is the inorganic compound with the formula CdS. Cadmium sulfide is a yellow solid.Egon Wiberg, Arnold Frederick Holleman (2001''Inorganic Chemistry'' Elsevier It occurs in nature with two different crystal structures as the rare mi ...
is formed. A red modification of the sulfide is formed under boiling conditions.
When with
caustic soda
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions .
Sodium hydroxide is a highly caustic base and alkali ...
solution, cadmium oxide forms precipitate of
cadmium hydroxide. Many insoluble cadmium salts are obtained by such precipitation reactions.
References
External links
{{nitrates
Cadmium compounds
Nitrates
Deliquescent substances
IARC Group 1 carcinogens