hydronium perchlorate
{{Chembox
|Name = Hydronium perchlorate
|OtherNames = {{Unbulleted list
| Oxonium perchlorate
| Perchloric acid monohydrate
}}
|ImageFileL1 = Hydronium-3D-balls.png
|ImageCaptionL1 = Hydronium cation, {{chem2|[H3O]+}}{{legend|red|Oxygen, O}}{{legend|white|Hydrogen, H}}
|ImageFileR1 = Perchlorate-3D-balls.png
|ImageCaptionR1 = Perchlorate anion, {{chem2|ClO4−}}{{legend|lime|Chlorine, Cl}}{{legend|red|Oxygen, O}}
|Section1 = {{Chembox Identifiers
|CASNo = 13444-99-0
|CASNo_Ref = {{cascite|correct|CAS}}
|ChemSpiderID = 25936644
|PubChem = 85613441
|SMILES = [OH3+].[O-][Cl](=O)(=O)=O
|StdInChI=1S/ClHO4.H2O/c2-1(3,4)5;/h(H,2,3,4,5);1H2
|StdInChIKey=AIUIJBDEQKTMHT-UHFFFAOYSA-N
}}
|Section2 = {{Chembox Properties
|Formula = {{chem2|[H3O]ClO4}}
|H=3|Cl=1|O=5
|Appearance = Colorless solid
|Density = 1.96 g/cm3
|MeltingPtC = 45
}}
|Section3 = {{Chembox Structure
|CrystalStruct = Orthorhombic
|SpaceGroup = Pnma
|LattConst_a = 9.2343 Å
|LattConst_b = 5.8178 Å
|LattConst_c = 7.4606 Å
}}
|Section4 = {{Chembox Related
|OtherAnions = Hydronium chloride
|OtherCations = Perchloric acid
}}
}}
Hydronium perchlorate is an inorganic chemical compound with the chemical formula {{chem2|[H3O]ClO4|auto=1}}. It is an unusual salt due to it being a solid and stable hydronium salt. It consists of hydronium cations {{chem2|[H3O]+}} and perchlorate anions {{chem2|ClO4−}}.
Production
Hydronium perchlorate is produced by the reaction of anhydrous perchloric acid and water in a 1:1 molar ratio:{{cite journal |author1=C. E. Nordman |title=The crystal structure of hydronium perchlorate at -80°C |journal=Acta Crystallographica |date=1962 |volume=15 |issue= 1|pages=18–23 |doi=10.1107/S0365110X62000055 |language=en|doi-access=free|bibcode=1962AcCry..15...18N }}
:{{chem2|HClO4 + H2O → [H3O]+ClO4−}}
A more analytically reliable method was reported using the macrocyclic Schiff base of sodium 2,6-diformyl-4-methylphenolate and 2,6-diformyl-4-methylphenol as a chelating agent to sequester Cu(II): transmetallation of the macrocycle with copper(II) perchlorate yielded colorless crystals of hydronium perchlorate.
It can also be produced by the reaction of anhydrous nitric acid and perchloric acid.{{cite book |author1=Kenneth Schofield |title=Aromatic nitration |date=1980 |publisher=Cambridge University Press |isbn=9780521233620 |page=30 |language=en|chapter=3}}{{cln|reason=By what chemical reaction?|date=April 2024}}