h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I am researching ozone for a university project. Ozone is an incredibly powerful antibacterial agent due to it's great oxidative potential. What I can't figure out is what it is about ozone and it's chemical properties that makes it such a powerful oxidising agent. Can anyone help? Also, is it true that ozone is what gives washing a freshly laundered smell?

Ozone is a somewhat unstable form oxygen - it is actually three oxygen atoms bonded together in a certain way, termed "resonance" in chemistry. Resonance can be thought of as a special, partial double-bond. In the case of ozone, one can imagine there oxygen atoms bonded together in a chain where the middle oxygen atom sort of acts as a middle part of a see saw where the third bond is shared between either of the two partner oxygen atoms. Hmm, that was a pretty bad explanation, but it'll have to do for this forum without the aid of pictures.

Anyway, ozone is indeed a much more powerful oxidizing agent than molecular oxygen (O2), a property that is due to the inherent instability of the chemical bonds holding it together. Probably the simplest thing is to not go much further and just say that, in general, resonance bonding in a non-cyclic compound is inherently unstable simply due to how the electrons are shared. This has more to do with the Pauli Exlcusion Principle than any electrostatic charge repulsion as is explained by chemical bond theory, and can be verified by models that predict the observed bond length of ozone (1.28 angstrom) and from the bond angle expected with sp2 orbital hybridization -- but I digress.

Not sure what if any amount of ozone is responsible for a freshly laundered smell. As for ozone being added (maybe not what you asked, but...), that ozone would most likely react very early in the washing cycle with various other ions present, not to mention the organic material that's a part of all dirt on our clothing. Incidentally, organic compounds react readily with ozone at room temperature. No, I suspect the smell of fresh laundry is due mostly to the perfumes that are put in washing detergents and/or fabric softeners. Having said that, there's no reason why some ozone couldn't form in an electric clothes dryer, particularly with all the static electrical discharges and other electrical potentials around the heating elements. Our noses are quite sensitive to ozone, so there might be something to that "fresh laundry smell" that is due to ozone, but that's really very subjective. One should compare to a natural gas fired clothes dryer to see if the "fresh laundry smell" was still there; if not the case, then it most likely would not be due to ozone at all.

- JD

The gremlin in my keyboard made me type, "...one can imagine there oxygen atoms bonded together in a chain where..."

Pls change "there" to "three" as you read the above sentence. Thank you.

- JD

If you want to know what Ozone smells likes, get close to a lazer printer or photocopier after it has been working hard - thats Ozone. Incidently, Ozone is toxic. As suggested by JD, because it is unstable, Ozone will break down very easily in a normal atmospheric conditions reverting to O2.

Donald