Freon nomenclature

Regarding Refrigerant numbering:  I agree with that 35 is not a useable
code for standard refrigerants.  The numbering system is based on an
"add 90 rule." Take the number and add 90.  This will give you a three
digit number.  The digits represent the particles per molecule of
carbon, hydrogen and fluorine in order.  Freon 11, for example has a
"magic" number of 101 (11 + 90).  This means 1 atom of carbon, 0 atoms
of hydrogen and 1 atom of fluorine on the molecule.  Since carbon has 4
spots to bond onto, there must be 3 atoms of chlorine also.  The
molecule then has a formula of CCl3F (which it does.) Those compounds
with bromine instead of chlorine are signified by a "B" in the number.
Refrigerant 13B1 for example tells us that it has 1 bromine. 13 + 90 =
103 and therefore the rest of the molecule is 1 carbon, 0 hydrogens and
3 fluorines.  All 100's have 2 atoms of carbon and therefore a total of
8 - 2 = 6 bonding sites for fluorine, chlorine, (bromine) and hydrogen.
Two bonding sites are of course taken up by the bond between the two
carbons. Only refrigerants 500 and 502 don't follow the rule.  These are
azeotropes of CCl2F2 (73.8 wt%)/C2H4F2 (26.2 wt %) and CHClF2 (48.8 wt
%)/C2ClF5 (51.2 wt %) respectively.

-Doug

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                  Conservation DistList Instance 6:23
                 Distributed: Sunday, October 18, 1992
                        Message Id: cdl-6-23-001
                                  ***