cobalt(III) hydroxide

{{chembox

| Watchedfields = changed

| verifiedrevid =

| Name = Cobalt(III) hydroxide

| ImageFile =

| ImageSize =

| ImageCaption =

| ImageFile2 =

| ImageSize2 =

| ImageCaption2 =

| IUPACName = Cobalt(III) hydroxide

| OtherNames = Cobaltic hydroxide

|Section1={{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 8278661

| InChI =

| SMILES = [OH-].[OH-].[OH-].[Co+3]

| InChIKey =

| StdInChI_Ref = {{stdinchicite|correct|pubchem}}

| StdInChI = 1S/Co.3H2O/h;3*1H2/q+3;;;/p-3

| StdInChIKey_Ref = {{stdinchicite|correct|pubchem}}

| StdInChIKey = FXVNMSSSMOVRTC-UHFFFAOYSA-K

| CASNo_Ref = {{cascite|correct|CAS}}

| CASNo = 1307-86-4

| PubChem = 10103133

| RTECS =

| UNII = S42YMM16W7

| EC_number = 215-153-0

}}

|Section2={{Chembox Properties

| Formula = Co(OH)₃

| MolarMass = 109.95522 g

| Appearance = brown-black or dark green powder

| Density =

| Solubility =

| SolubleOther =

| SolubilityProduct =

| MeltingPtC =

| MeltingPt_notes =

| BoilingPt =

}}

|Section3={{Chembox Structure

| MolShape =

| Coordination =

| CrystalStruct =

| Dipole =

}}

|Section4={{Chembox Thermochemistry

| DeltaHf =

| DeltaHc =

| Entropy =

| HeatCapacity =

}}

|Section7={{Chembox Hazards

| ExternalSDS =

| MainHazards =

| GHSPictograms = {{GHS07}}{{GHS08}}

| GHSSignalWord = Danger

| HPhrases = {{H-phrases|319|334|413}}

| PPhrases = {{P-phrases|261|264|273|280|285|304+341|305+351+338|337+313|342+311|501}}

}}

|Section8=

}}

Cobalt(III) hydroxide or cobaltic hydroxide is a chemical compound with formula {{chem|Co|(|OH|)|3}} or {{chem|H|3|Co|O|3}}. It is an ionic compound, with trivalent cobalt cations {{chem|Co|3+}} and hydroxyl anions {{chem|OH|-}}.

The compound is known in two structurally different forms, "brownish-black" and "green". The brownish-black form is a stable solid and can be prepared by reaction of water solutions of cobalt(II) chloride and sodium hydroxide, followed by oxidation with ozone.Pankratov, D.A., Veligzhanin, A.A., and Zubavichus, Y.V. (2013): "Structural Features of Green Cobalt(III) Hydroxide". Russian Journal of Inorganic Chemistry, volume 58, issue 1, pages 67–73. {{doi|10.1134/S0036023613010142}}

The green form, formerly thought to be cobalt(II) peroxide, apparently requires carbon dioxide as a catalyst. It can be prepared by adding hydrogen peroxide to a solution of cobalt(II) chloride in 96% ethanol at –30 to –35°C, then adding a 15% solution of sodium carbonate in water with intense stirring. The resulting dark green powder is fairly stable at liquid nitrogen temperature, but at room temperature it turns dark brown within a few days.Pankratov, D.A., Portachenko, T.A., and Perfil’ev, Y.D. (2008): "Emission Mössbauer Study of 'Cobalt Peroxide'". Moscow University Chemical Bulletin, volume 63, issue 5, pages 292–296. {{doi|10.3103/S002713140805012X}}