In the polyatomic ion, CrO4 -2, what is the charge on the chromium atom?

1 Answer
Nov 12, 2015

Answer:

The oxidation state of #Cr# in chromate ion, #CrO_4^(2-)#, is #VI^+#.

Explanation:

As far as anyone knows, the charge in chromate is localized on the oxygen (i.e #(O=)_2Cr(-O^-)_2#). Chromic acid, #H_2CrO_4# (or #(O=)_2Cr(-OH)_2#), is the precursor; this is a potent oxidant. In each case, the metal oxidation state (#VI^+#) is clear. Note that in this formal representation, the charge on chromium is neutral. The negative charge is borne by the 2 singly bound oxygen atoms.