Tetramminecopper(II) sulfate
Encyclopedia
Tetraamminecopper sulfate is the inorganic compound
with the formula [Cu(NH3)4(H2O)n]SO4. This dark blue solid is a metal complex
. It is closely related to Schweizer's reagent
, which is useful for the production of cellulose
fibers in the production of rayon
.
solution, NH3, to a saturated aqueous solution
of copper sulfate [Cu(H2O)6]SO4 until all the copper(II) hydroxide that is initially formed redissolves into a deep blue solution. The deep blue crystalline solid tends to hydrolyze
and lose ammonia ligands upon standing in air.
In the solid state, the salt consists of the [Cu(NH3)4H2O]2+ cation, which has a square pyramidal molecular geometry
. The Cu-N and Cu-O distances are about 210 and 233 pm.
and copper alloys
where attack from ammonia has occurred leading to cracking. The problem was first found in ammunition cartridge cases when they were stored near animal waste, which produced trace amounts of ammonia. It is known as season cracking
.
Inorganic compound
Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...
with the formula [Cu(NH3)4(H2O)n]SO4. This dark blue solid is a metal complex
Complex (chemistry)
In chemistry, a coordination complex or metal complex, is an atom or ion , bonded to a surrounding array of molecules or anions, that are in turn known as ligands or complexing agents...
. It is closely related to Schweizer's reagent
Schweizer's reagent
Schweizer's reagent is the chemical complex tetraamminediaquacopper dihydroxide, [Cu42]2. It is prepared by precipitating copper hydroxide from an aqueous solution of copper sulfate using sodium hydroxide or ammonia, then dissolving the precipitate in a solution of ammonia.When the entire amount of...
, which is useful for the production of cellulose
Cellulose
Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....
fibers in the production of rayon
Rayon
Rayon is a manufactured regenerated cellulose fiber. Because it is produced from naturally occurring polymers, it is neither a truly synthetic fiber nor a natural fiber; it is a semi-synthetic or artificial fiber. Rayon is known by the names viscose rayon and art silk in the textile industry...
.
Preparation, structure, properties
This compound can be prepared by treating concentrated ammoniaAmmonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
solution, NH3, to a saturated aqueous solution
Solution
In chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...
of copper sulfate [Cu(H2O)6]SO4 until all the copper(II) hydroxide that is initially formed redissolves into a deep blue solution. The deep blue crystalline solid tends to hydrolyze
Hydrolysis
Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...
and lose ammonia ligands upon standing in air.
In the solid state, the salt consists of the [Cu(NH3)4H2O]2+ cation, which has a square pyramidal molecular geometry
Molecular geometry
Molecular geometry or molecular structure is the three-dimensional arrangement of the atoms that constitute a molecule. It determines several properties of a substance including its reactivity, polarity, phase of matter, color, magnetism, and biological activity.- Molecular geometry determination...
. The Cu-N and Cu-O distances are about 210 and 233 pm.
Corrosion
The charactersitic deep blue colour of the tetraamine complex is found in brassBrass
Brass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...
and copper alloys
Copper alloys
Copper alloys are metal alloys that have copper as their principal component. They have high resistance against corrosion. The best known traditional types are bronze, where tin is a significant addition, and brass, using zinc instead...
where attack from ammonia has occurred leading to cracking. The problem was first found in ammunition cartridge cases when they were stored near animal waste, which produced trace amounts of ammonia. It is known as season cracking
Season cracking
Season cracking is a form of stress-corrosion cracking of brass cartridge cases originally reported from British forces in India. During the monsoon season, military activity was temporarily reduced, and ammunition was stored in stables until the dry weather returned. Many brass cartridges were...
.