The “dichlorodiphenyl bit refers to the two benzene rings (called phenyl groups), each one with a chlorine atom on it (conveniently labelled “Cl”). They are both attached to a two carbon chain (ethane), the other carbon of which has had all its hydrogens replaced with three chlorine atoms (trichloro).
If that is OK with you – this is where it gets bd. The name was used in the agrochemical industry at a time when people were less rigorous and it is in fact not correct!!! The correct name for DDT is:
1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane which would probably have given it an acronym of TBCE. However, don’t worry – no unscrupulous manufacturer is going to get away with trying to sell it under that name will get away with it. The authorities are wise to that one!
Thanks Laurence for the correction 🙂
DDT was used heavily in the 1960’s for pest control (insects, mosquitos, lice). One problem was that some insects and pests became resistent to DDT. The DDT spread on crops was then consumed by humans and it was found that the DDT stayed in our bodies as a toxin. It concentrated in places like the thyroid, liver, kidneys and fatty tissues. DDT also ended up in our water courses as it washed off the land, and then it ended up in fish (that we eat), and in birds (as they eat the insects). Bird egg shells were found to get thinner making reproduction difficult and endangering ceratin species. So, all in all, whatever it’s name, it’s not nice stuff. We have learned a lot of lessons about toxins and pesticides since this time and have more thorough testing procedures now. 🙂