Meerwein s salt trimethyloxonium

Oxonium ions have three bonds to a positively charged oxygen atom. All three bonds can be a bonds as in H30 or Meerwein s salt, trimethyloxonium fluoroborate, a stable (though reactive) compound described in Chapter 21, or one bond can be art bond as in the acetal intermediate. The term oxonium ion describes either of these structures. They are like alkylated ethers or 0-alkylated carbonyl compounds. 

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