What are the oxidation states of copper?

2 Answers
Jun 24, 2017

This is too broad a question, you can't memorize its oxidation states, per se, but you can rationalize what it is by memorizing the rules for common anions it usually bonds with!


For instance,

#CuSO_4# — copper (II) sulfate
#x + (+6) + (-8) = 0#

We know sulfate's charge is 2-, and we also memorize that an oxide anion has an oxidation state of 2-, unless its a peroxide in which case its charge is 1-, but that's another question!

So, solving this 8th grade algebra problem, we get:

#x -2 = 0#
#x = 2#

Thus, in this particular compound, copper's oxidation state is 2+!

Jun 24, 2017

-2, +1, +2, +3, +4


Copper can have any of the above oxidation states, however +1 and +2 are the most common.

An example of a +2 oxidation state is CuO, where oxygen has an oxidation number of -2 and therefore copper has the oxidation number of +2 to balance out the molecule.

An example of a +1 oxidation state is Cu2O, where, once again, oxygen's oxidation state is -2 and so to balance out the molecule, each copper atom is +1.