osmium diammine hydroxide
{{original research|date=June 2025}}
{{Chembox
| Name = Osmium diammine hydroxide
| ImageFile = Osmium diammine hydroxide.jpg
| ImageCaption = Osmium diammine hydroxide stored in water.
| ImageSize =
| ImageAlt =
| OtherNames = Osmium oxydiammine-dihydroxide, {{r|Mellor|p=704}}Oxyosmiumamine hydroxide,{{cite book |last1=Comey |first1=Arthur Messinger |title=A Dictionary of Chemical Solubilities: Inorganic |date=1896 |publisher=Macmillan and Company |page=279 |url=https://books.google.com/books?id=H9bPAAAAMAAJ&pg=PA279|access-date=16 June 2025 |language=en}} osmosyldiammine hydroxide, {{r|CAM}} ammonio-sesquioxide of osmium {{r|Cavendish1852|p=415}}
| Section1 = {{Chembox Properties
| Formula = {{chem2|[OsO(NH3)2](OH)2}}
| MolarMass =
| Appearance = brown powder {{r|JNF|p=231}}
| Solubility = insoluble {{r|CAM}}
| SolubleOther = dissolves in acids
}}
}}
Osmium diammine hydroxide is an inorganic chemical compound with the formula {{chem2|[OsO(NH3)2](OH)2}}.{{cite book|author1=J. Newton Friend|chapter=Osmium and its compounds|title=A textbook of inorganic chemistry, vol.IX Part I Cobalt, Nickel, and The Elements of The Platinum Group|publisher=Charles Griffin and Company, Limited|date=1920|place=London|pages=216-231|url=https://dn790003.ca.archive.org/0/items/textbookinorgani00libg_516/textbookinorgani00libg_516.pdf|access-date=17 June 2025}} {{rp|p=231}} It exists as a brown powder that is insoluble in water.{{r|JNF}}{{r|CAM}}
Synthesis
Osmium diammine hydroxide can be produced by reducing osmium tetroxide with aqueous ammonia at 50°C.{{r|Cavendish1852}}{{cite book|author1=Prakash Satya|chapter=Platinum Metals-IV:Osmium|title=Advanced Chemistry of Rare Elements, 5th Ed. |publisher=S Chand and Company Limited|year=2013|place=India|pages=611-612}}{{r|JNF|p=231}} It can also be produced by treating hexachloroosmates with ammonia. {{r|JNF|p=216}}
Properties
Osmium diammine hydroxide decomposes explosively when heated in air, releasing nitrogen gas.{{r|Cavendish1852}}{{cite book|author1=J.W. Mellor|chapter=Osmium|title=A comprehensive treatise on inorganic and theoretical chemistry, Volume 15|publisher=Longmans, Green and Co|date=May 1936|place=London|pages=704-720|url=https://archive.org/details/Mellor13/Mellor_15/page/n711/mode/2up?q=%5BOsO%28NH3%292%5D%28OH%292|access-date=16 June 2025}} {{rp|p=704}}
When heated to boiling in concentrated alkali hydroxide solutions, osmium diammine hydroxide releases ammonia and decomposes to osmium dioxide.{{r|Mellor|p=705}}{{r|JNF|p=231}}
It dissolves in acids to produce corresponding salts, such as osmium diammine chloride, {{chem2|[OsO(NH3)2]Cl2}}.{{r|Mellor|p=720}}{{r|JNF|p=231}}
Osmium diammine chloride.png|A solution of osmium diammine chloride.