ammonium hexachloroosmate(IV)
{{Chembox
| Name = Ammonium hexachloroosmate(IV)
| ImageFile = (NH4)2OsCl6(s).jpg
| ImageCaption = Microcrystals of ammonium hexachloroosmate
| ImageSize =
| ImageAlt = Microcrystals of ammonium hexachloroosmate
| IUPACName = Ammonium hexachloroosmate(IV)
| OtherNames =
| Section1 = {{Chembox Identifiers
| CASNo = 12125-08-5
| ChemSpiderID = 145801
| UNII =
| DTXSID =
| EINECS = 235-188-5
| PubChem = 11729867
| StdInChI = 1S/6ClH.2H3N.Os/h6*1H;2*1H3;/q;;;;;;;;+4/p-4
| StdInChIKey = SRBXXQDKBKTWOC-UHFFFAOYSA-J
| SMILES = [NH4+].[NH4+].Cl[Os-2](Cl)(Cl)(Cl)(Cl)Cl
}}
| Section2 = {{Chembox Properties
| N=2|H=8|Os=1|Cl=6
| MolarMass =
| Appearance = red crystals
| Density = 2.93 g/cm3
| MeltingPt = 170
| BoilingPt =
| Solubility = poorly soluble
}}
| Section3 = {{Chembox Hazards
| GHSPictograms = {{GHS07}}{{cite web |title=Ammonium hexachloroosmate(IV) |url=https://www.sigmaaldrich.com/RU/en/product/aldrich/209074 |publisher=Sigma Aldrich |access-date=17 October 2024}}
| GHSSignalWord = Warning
| GHS_ref =
| HPhrases =
| MainHazards =
| FlashPt =
| AutoignitionPt =
}}
}}
Ammonium hexachloroosmate(IV) is an inorganic chemical compound with the chemical formula {{chem2|(NH4)2OsCl6}}.{{cite web |title=Ammonium Hexachloroosmate |url=https://www.americanelements.com/ammonium-hexachloroosmate-12125-08-5 |publisher=American Elements |access-date=17 October 2024 |language=en}}{{cite book |last1=Brauer |first1=Georg |title=Handbook of Preparative Inorganic Chemistry V2 |date=2 December 2012 |publisher=Elsevier |isbn=978-0-323-16129-9 |page=1603 |url=https://books.google.com/books?id=Pef47TK5NfkC&dq=Ammonium+hexachloroosmate(IV)&pg=PR20 |access-date=17 October 2024 |language=en}}
Synthesis
Ammonium hexachloroosmate(IV) can be produced by the reduction of osmium(VIII) oxide with iron dichloride in an acidic medium in the presence of ammonium ions:{{cite book |last1=Dwyer |first1=F. P. |last2=Hogarth |first2=J. W. |last3=Rhoda |first3=Richard N. |title=Inorganic Syntheses |chapter=Ammonium Hexachloroosmate(IV) |series=Inorganic Syntheses |date=January 1957 |volume=5 |pages=206–207 |doi=10.1002/9780470132364.ch60 |isbn=978-0-470-13164-0 |access-date=17 October 2024|chapter-url=https://onlinelibrary.wiley.com/doi/10.1002/9780470132364.ch60}}{{cite book |title=Inorganic Syntheses, Volume 5 |date=22 September 2009 |publisher=John Wiley & Sons |isbn=978-0-470-13268-5 |page=206 |url=https://books.google.com/books?id=ZiepD3jLCp4C&dq=Ammonium+hexachloroosmate(IV)&pg=PA206 |access-date=17 October 2024 |language=en}}
::{{chem2|OsO4 + 4FeCl2 + 8HCl + 2NH4Cl -> (NH4)2[OsCl6] + 3FeCl3 + 4H2O}}
Physical properties
Ammonium hexachloroosmate(IV) forms dark red crystals of the cubic system,{{cite book |last1=Armarego |first1=W. L. F. |title=Purification of Laboratory Chemicals: Part 2 Inorganic Chemicals, Catalysts, Biochemicals, Physiologically Active Chemicals, Nanomaterials |date=27 August 2022 |publisher=Butterworth-Heinemann |isbn=978-0-323-95828-8 |page=7 |url=https://books.google.com/books?id=bN5sEAAAQBAJ&dq=Ammonium+hexachloroosmate(IV)&pg=PA7 |access-date=17 October 2024 |language=en}} space group Fm3m, cell parameters a = 0.9729 nm, Z = 4.
It is poorly soluble in cold water.{{cite book |last1=Haynes |first1=William M. |title=CRC Handbook of Chemistry and Physics, 94th Edition |date=19 April 2016 |publisher=CRC Press |isbn=978-1-4665-7115-0 |page=4-46 |url=https://books.google.com/books?id=MmDOBQAAQBAJ&dq=Ammonium+hexachloroosmate(IV)&pg=SA4-PA46 |access-date=17 October 2024 |language=en}}
Chemical properties
The compound is reduced by hydrogen to metallic osmium:{{cite book |chapter-url=https://onlinelibrary.wiley.com/doi/10.1002/9780470132555.ch73|last1=Lay |first1=Peter A. |last2=Magnuson |first2=Roy H. |last3=Taube |first3=Henry |last4=Vassilian |first4=Asbed |title=Inorganic Syntheses |chapter=Pentaammineosmium(III) and Hexaammineosmium(III) Complexes |date=January 1986 |volume=24 |pages=269–277 |doi=10.1002/9780470132555.ch73 |isbn=978-0-471-83441-0 |access-date=17 October 2024}}{{cite journal |last1=Meyer |first1=Gerd |last2=Möller |first2=Angela |title=Thermolysis of ternary ammonium chlorides of rhenium and the noble metals |journal=Journal of the Less Common Metals |date=30 June 1991 |volume=170 |issue=2 |pages=327–331 |doi=10.1016/0022-5088(91)90336-3 |url=https://www.sciencedirect.com/science/article/abs/pii/0022508891903363 |access-date=17 October 2024 |issn=0022-5088|url-access=subscription }}
::{{chem2|3(NH4)2[OsCl6] -> 3Os + 2N2 + 16HCl + 2NH4Cl}}
::{{chem2|(NH4)2[OsCl6] + 2H2 -> Os + NH4Cl + 4HCl}}
Similar to sodium hexachloroosmate, ammonium hexachloroosmate decomposes to osmium dioxide when exposed to strong alkali, and reacts with ammonia to produce osmium diammine hydroxide, {{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|url=https://dn790003.ca.archive.org/0/items/textbookinorgani00libg_516/textbookinorgani00libg_516.pdf|access-date=17 June 2025}}
Uses
The compound is used as a pharmaceutical, organic, and chemical intermediate.{{cite web |title=Ammonium hexachloroosmate(IV), 99.9% (metals basis), Os 42.5% min, Thermo Scientific Chemicals |url=https://www.fishersci.fi/shop/products/ammonium-hexachloroosmate-iv-99-9-metals-basis-os-42-5-min-thermo-scientific/11320118 |publisher=Fisher Scientific |access-date=17 October 2024}}