Every wonder what
CFC-12 and
CFC-134A and all those numbers mean? There's a simple rule for finding out the chemical structure. Take for example CFC-134, the stuff that they're using now in cars. Start with the number 134 and add 90:
1 3 4
+ 9 0 the magic conversion number
_____
2 2 4
Here's the rule, the first 2 is the number of
carbons, the second 2 the number of
hydrogens, and the 4 the number of
fluorines. Any leftover
valences are filled with
chlorines. Thus, CFC-134 looks like:
F F
| |
H-C-C-H
| |
F F
or some isomer thereof. An A after the name signifies a asymmetric stereoisomer. Since all the valences are filled with hydrogens and fluorines, there is no room left for chlorine. That's why this compound is used now instead of CFC-12, the refrigerant that's now been banned:
1 2
+ 9 0
_____
1 0 2
So - one carbon, no hydrogens, 2 fluorines and the rest chlorines. This looks like:
F
|
Cl-C-F
|
Cl
This is the stuff that's so bad for the
ozone layer.
A little piece of 'industrial espionage' (TWAJS) I got from a friend at Dupont.