# Oxidation state of TiO2?

Hi there! I have a quick question that could use some clarification. According to my textbook, an oxygen atom has an oxidation state of -1 when in the polyatomic ion peroxide, although it's -2 in most other cases. However, I've come across this problem where it asks for the oxidation state of Ti in the compound TiO2. I figured it was +2 since each oxygen atom carries an oxidation state of -1 (because it's a peroxide) and -1(2) is -2, so Ti must have an oxidation state of +2, right? But then when I try to ease my qualms, every single post on the Internet points toward an oxidation state of +4. I don't understand! Is this titanium peroxide or titanium dioxide? Any help would be greatly appreciated.

~christina~
Gold Member
Hi there! I have a quick question that could use some clarification. According to my textbook, an oxygen atom has an oxidation state of -1 when in the polyatomic ion peroxide, although it's -2 in most other cases. However, I've come across this problem where it asks for the oxidation state of Ti in the compound TiO2. I figured it was +2 since each oxygen atom carries an oxidation state of -1 (because it's a peroxide) and -1(2) is -2, so Ti must have an oxidation state of +2, right? But then when I try to ease my qualms, every single post on the Internet points toward an oxidation state of +4. I don't understand! Is this titanium peroxide or titanium dioxide? Any help would be greatly appreciated.
Peroxides technically have the oxygens bonded to each other. TiO2 is titanium dioxide. It has a oxidation state of +4 because the two oxygens are not bonded to each other and each have an oxidation state of -2. (Two oxygens each having -2 state vs. peroxide oxygen which has O2 (-2) state)

Borek
Mentor