OxoniumIon
An oxonium ion is a positively charged polyatomic ion where oxygen is bonded to three other atoms. It is essentially a protonated alcohol or ether. The most common example is the hydronium ion, H₃O⁺, which forms when a Brønsted-Lowry acid donates a proton to a water molecule. In this case, the oxygen atom in water accepts a proton, resulting in a net positive charge distributed across the molecule. Other examples include protonated ethers (R-O⁺H-R') and protonated alcohols (R-O⁺H₂).
Oxonium ions are important intermediates in many chemical reactions, particularly in acid-catalyzed reactions. Their reactivity stems