Tetraamminecopper(II) sulfate: Difference between revisions

| verifiedrevid = 447611336

| Name = Tetraamminecopper(II) sulfate monohydrate

| ImageFile =

| ImageName1 = Ball-and-stick model of the Tetramine copper(II) cation

| ImageCaption1 = Tetraamminecopper(II) sulfate monohydrate<br>{{legend|rgb(256, 128, 80)|[[Copper]], Cu}}{{legend|red|[[Oxygen]], O}}{{legend|blue|[[Nitrogen]], N}}{{legend|yellow|[[Sulfur]], S}}{{legend|white|[[Hydrogen]], H}}

| ImageCaption2 = Tetraamminecopper(II) sulfate monohydrate crystals

| IUPACName = Tetraammineaquacopper(II) sulfate

| OtherNames = {{ubl|Cuprammonium(II) sulfate|Cuprammonium(II) sulfate monohydrate|Cupric sulfate, ammoniated|Tetraamminecopper(II) sulfate monohydrate}}

| SystematicName =

| CASNo_Ref = {{cascite|correct|??}}

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = YMW7182547

| PubChem = 61513

| SMILES = [OH2+][Cu-3]([NH3+])([NH3+])([NH3+])[NH3+].[O-][S+2]([O-])([O-])[O-]}}

| Formula = {{chem2|[Cu(NH3)4(H2O)]SO4}}

| MolarMass = 245.79&nbsp;g/mol (monohydrate)

| Odor = Ammonia

| Density = 1.81&nbsp;g/cm³

| BoilingPtC = 330

| BoilingPt_ref =

| Solubility = 18.5&nbsp;g/(100&nbsp;g) (21.5&nbsp;°C)<ref name=Brauer/>}}

| AutoignitionPt =

| Section4 =

| Section5 =

| Section6 =

}}

[[File:Сульфат тетраамминмеди.jpg|alt=Tetraamminecopper(II) sulfate|thumb|Tetraaminecopper(II) sulfate monohydrate milled]]

[[File:Иодид тетраамиинмеди.jpg|alt=Tetraamminecopper(II) iodide|thumb|Analogous compound with different anion: tetraamminecopper(II) iodide monohydrate]]

'''Tetraamminecopper(II) sulfate monohydrate''', or more precisely '''tetraammineaquacopper(II) sulfate''', is the [[salt (chemistry)|salt]] with the formula {{chem2|[Cu(NH3)4]SO4*H2O|auto=1}}, or more precisely {{chem2|[[copper|Cu]]([[ammonia|NH3]])4([[water|H2O]])][[sulfate|SO4]]}}. This dark blue to purple solid is a [[sulfuric acid]] salt of the [[Complex (chemistry)|metal complex]] {{chem2|[Cu(NH3)4(H2O)](2+)}} (tetraammineaquacopper(II) [[cation]]). It is closely related to [[Schweizer's reagent]], which is used for the production of [[cellulose]] fibers in the production of [[rayon]].

==Synthesis==

This compound can be prepared by adding concentrated [[aqueous solution]] of [[ammonia]] to a [[saturated solution|saturated]] aqueous solution of [[copper(II) sulfate pentahydrate]] followed by precipitation of the product with [[ethanol]] or [[isopropanol]].<ref name=Brauer>Editor G.Brauer "Tetraamminecopper (II) Sulfate" Handbook of Preparative Inorganic Chemistry, 2nd Ed., Academic Press, 1965, New York. Vol. 2. p. 1021.</ref>

:{{chem2|4 NH3 + CuSO4*5H2O → [Cu(NH3)4(H2O)]SO4 + 4 H2O}}

==Chemical reaction and solubility==

The deep blue crystalline solid tends to [[hydrolyse]] and evolve (release) ammonia upon standing in air.<ref name=Brauer/> It is fairly soluble in water. The brilliant dark blue-violet color of tetraamminecopper(II) sulfate solution is due to presence of {{chem2|[Cu(NH3)4](2+)}} (tetraamminecopper(II) cation). Often, the dark blue-violet color is used as a positive test to verify the presence of {{chem2|Cu(2+)}} in a solution.

== Structure and properties ==

The solid state structure of tetraamminecopper(II) sulfate monohydrate confirms that the compound is a [[salt (chemistry)|salt]]. The [[Metal complex|complex]] [[cation]] is {{chem2|[Cu(NH3)4(H2O)](2+)}} (tetraammineaquacopper(II) cation), which has a [[square pyramidal molecular geometry]]. The [[copper|Cu]]-[[nitrogen|N]] and Cu-[[oxygen|O]] bond length are about 210 and 233&nbsp;[[picometre|pm]], respectively, as determined by [[X-ray crystallography]].<ref>{{cite journal|author=B. Morosin|title=The Crystal Structures of Copper Tetraammine Complexes. A. Cu(NH₃)₄SO₄^.H₂O and Cu(NH₃)₄SeO₄|journal=Acta Crystallographica|year=1969|volume=B25|issue=1 |pages=19–30|doi=10.1107/S0567740869001725|bibcode=1969AcCrB..25...19M}}</ref> The correct concentrations of [[ammonia]] and [[copper(II) sulfate]] solution needed to synthesize the complex can be determined by [[colorimetry]]. The combination of the correct concentrations will produce the highest [[absorbance]] read out on the [[Colorimeter (chemistry)|colorimeter]] and as a result the formula of the complex can be verified.

The characteristic deep blue colour of the tetraammine complex is found in [[brass]] and [[copper alloys]] where attack from ammonia has occurred, leading to cracking. The problem was first found in [[Cartridge (firearms)|ammunition cartridge]] cases when they were stored near [[animal waste]], which produced trace amounts of ammonia. This type of corrosion is known as [[season cracking]].

==Uses==

The closely related [[Schweizer's reagent]] is used for the production of [[cuprammonium rayon]].

[[Category:Copper complexes]]