Copper forms compounds in the oxidation states of +1 (cuprous) and +2 (cupric);
trivalent copper survives no more than a few seconds in an aqueous solution. The
relatively small change in electrochemical potential between the cuprous and
cupric ions in solution gives the usefulness of copper compounds in chemical
reactions. Copper compounds are used as catalysts in reactions, especially
oxidation (cupric chloride) and heterogeneous reactions. Cupric chloride, copper
chloride (CuCl2) is a yellowish to brown, deliquescent powder; soluble in water,
alcohol, and ammonium chloride; while the dihydrated form of cupric chloride is
a green crystals; soluble in water. It is used as a mordant in dyeing and
printing textile fabrics and in the refining of copper, gold, and silver as well
as a catalyst in chemical reactions. Cuprous chloride (CuCl or Cu2Cl2), also
known as resin of copper, is a green, tetrahedral crystals; insoluble in water.
The biological property of copper compounds takes important role in as
fungicides in agriculture and biocides in antifouling paints for ships and wood
preservations. Very low level of copper is toxic to fungi and algae but the
levels for mammal is much higher. The copper ions inhibit the metabolism of the
fungus when they react with sulfur containing enzymes in the plant. Copper
compounds form a protective barrier on the plant surface and thereby prevent
fungi from entering the plant host. The fungicidal effect of copper compounds as
non-systemic fungicides are such as bordeaux mixture, cupric hydroxide, copper
arsenate, copper carbonate, cuprous oxide, copper-8-quinolinolate, copper
oleate, copper sulfate, or copper oxychloride. Another important biological
application of copper compounds, such as copper sulfide is as an antifouling agent
in paints. The description and applications of copper compounds in
- Copper Arsenate, Cu3(AsO4)2·4H2O or Cu5H2(AsO4)4·2H2O;
bluish powder which is insoluble in water and alcohol, soluble in ammonium
hydroxide and dilute acids; used as a fungicide and insecticide.
Arsenite, also known
as Scheele's green, CuHAsO3 ;
toxic, green powder which is soluble in acids and
decomposes at the melting point; used as a pigment and insecticide;
- Copper Carbonate, artificial
malachite. Cu2(OH)2CO3, toxic, green powder
which is soluble in acids and decomposes at 200 C; used in pigments and
pyrotechnics and as a fungicide and feed additive; antidote for phosphorous
- Copper Gluconate [CH2OH(CHOH)4COO]2Cu.
light blue, crystalline powder which is soluble in water; used in
medicine and as a dietary supplement; scale removal in metal cleanings and can be formulated in cleaning compounds
including mouthwash due to its sequestering ability in alkaline conditions.
Oleate Cu[OOC(CH2)7CHCH(CH2)7CH3]2 ,
green to blue liquid, used as a fungicide
for fruits and vegetables; used in formulating antiseptics, deodorants, antiperspirants.
- Copper-8-Quinolinolate C18H14N2O2Cu,
khaki-colored solid which is insoluble in water; used as a fungicide in fruit
- Copper Sulfide CuS,
black, monoclinic or hexagonal crystals which decomposes at 220
C; used antifouling agent
- Cupric Acetate
(Copper Acetate), known as crystals of Venus, Cu(C2H3O2)2·H2O,
blue to green crystals which is soluble in water; used
as a raw material to make paris green; organic reaction catalyst; textile dyeing; fungicide.
- Cupric Bromide (Copper Bromide)
crystals; used in photography as an intensifier and in organic synthesis as a
- Cupric Chloride
(copper chloride) CuCl2,
yellowish to brown, deliquescent powder which is
in water, alcohol, and ammonium chloride; used as a mordant in dyeing
and printing textile fabrics and in the refining of copper, gold, and silver.
- Cupric Chromate (Copper Chromate) CuCrO4,
yellow liquid used as a mordant.
- Cupric Cyanide
(Copper Cyanide) Cu(CN)2,
green powder which is insoluble in water;
used in electroplating copper on iron.
Fluoride (Copper Fluoride) CuF2,
white crystalline powder used in ceramics and in the preparation
of brazing and soldering fluxes.
Hydroxide (Copper Hydroxide) Cu(OH)2,
blue microscopic crystals; used as a mordant and
pigment, in manufacture of many copper salts, and for staining paper.
- Cupric Nitrate (Copper Nitrate)
green powder or blue
crystals which is soluble in water; used in electroplating copper on iron; as
a catalyst and nitrating agent in organic reactions; component in rocket
fuel; fungicides and wood preservatives; textile dyeing and printing; pigment
- Cupric Oxide
(Copper Oxide) CuO, black, monoclinic crystals which
is insoluble in
water; used in making fibers and ceramics; in organic and gas analyses; catalyst, fungicide, antiseptic;
red pigment for glass, ceramics; antifouling gent;
- Cuprous Bromide
(Copper Bromide) Cu2Br2,
white or gray crystals
slightly soluble in cold water.
Chloride (Copper Chloride) CuCl or Cu2Cl2,
green, tetrahedral crystals which is insoluble in water;
used as a heat
and light stabilizer for nylon and as a catalyst
for chemical synthesis. used as a crude for
phthalocyanine blue pigments;
used as desulfuring agent in the refinery industry
- Cuprous Fluoride
(Copper Fluoride) Cu2F2,
crystalline powder which melts at 908 C.
- Cuprous Oxide
(Copper Oxide) Cu2O,
an oxide of copper found in nature as cuprite and formed
on copper by heat; used chiefly as a pigment and as a fungicide; soil additive;
colorant in ceramics; electroplating baths;
Copper sulfate is the common name for the blue crystalline
cupric sulfate, in which copper has valence +2. It may also refer to cuprous
sulfate (Cu2SO4), in which copper has valence +1. It is soluble in water but
insoluble in alcohol. It usually crystallizes as a pentahydrate compound
containing five molecules of water (CuSO4·5H2O) and is known in commerce as blue
vitriol. It is prepared by the treatment of copper oxides with sulfuric acid.
Cupric sulfate is the most important salt of copper. Cupric sulfate is utilized
chiefly for agricultural purposes, as a pesticide, germicide, feed additive, and
soil additive. It is also used as a raw material in the preparation of other
copper compounds, electrolyte for batteries and electroplating baths, and in
medicine as a locally applied fungicide, bactericide, and astringent. It also
finds wide use in the preparation of pigments. Copper is an essential trace
nutrient which performs a number of diverse functions in protein biochemistry.
Some copper compounds such as copper sulfate are used as a supplement for