I have learnt earlier that metal oxides with higher metal oxidation states are more acidic than those with less oxidation states, but copper disobeys this rule. Why?

  • 3
    $\begingroup$ There are many factors that affect basicity of a substance-electronegativity, size, resonance, etc. Its the cumulative effect of these factors that decide the relative order. What you learnt about the higher metal oxidation states being more acidic is more of a "shortcut" than a fact. Don't rely on them too much. $\endgroup$ – Arishta Feb 12 '17 at 18:11
  • 1
    $\begingroup$ Just stumbled upon this while searching...It'd be great if anyone wrote an answer to this question. Perhaps, an explanation of why the "higher oxidation state is more acidic" rule even worked in the first place would also help. $\endgroup$ – Gaurang Tandon Apr 6 '18 at 12:37
  • 1
    $\begingroup$ How do you find Cu(II) hydroxide more basic to start with? Reference? $\endgroup$ – Oscar Lanzi Apr 6 '18 at 21:11
  • $\begingroup$ I'm sorry. This is a question I asked a very long time back that I'm not able to recall the source $\endgroup$ – Aaron John Sabu Apr 9 '18 at 8:29

Your Answer


Browse other questions tagged or ask your own question.