Cl and O bonds together via covalent bonding.

although both element are electronegative, one element is more electronegative than the other, therefore one of them is relatively positive and the other relatively negative.

which element is the relative positive one? which element is the relative negative one?

mouthwash? i think it is more of a disinfectant for drinking water... pure ClO2 is explosive or so i heard

Thanks for your answer. Ok, chlorine is less negative than oxygen,i.e., relatively positive. But chlorine dioxide? I think it is sold as a mouthwash.  How would one manufacture that and keep it stable? Is it a scam?

Hcurious

ClO2 is not used as mouthwash, as others already pointed out. In this compound, Cl has the oxidation state +4 and oxygen has the oxidation state -2. But remember, the concept of oxidation state is just an administrative one. In reality, the bonds are covalent with some positive charge-bias towards the chlorine and some negative-charge bias towards the oxygen, but the chlorine certainly has no charge +4, it is much less.

Oxidation state and real charge only are the same for purely ionic compounds, consisting of simple ions, such as NaCl, Na2O, CaF2.