What symbol is used to show the standard reduction potential of an oxidation reaction in a half-cell?

The reduction potential of an oxidation reaction in a half-cell is denoted by the symbol E°.
Reduction potential is the tendency of a given chemical species to become reduced, that is, gain electrons or undergo a decrease in oxidation number. The greater the reduction potential, the more likely that a species will be reduced.

Talc (french chalk) is the ingredient