Stuart Altmann on sat 23 mar 96
To Joanne Grant:
Can I take you up on your offer to help with chemistry questions? The
original-formula Calgon water softener (no longer available, apparently)
was said to be an excellent deflocculant for glazes. I have seen two
identifications of its composition. One is that it was tetrasodium
pyrophosphate, the other, that it was sodium hexa-metaphosphate. So, two
questions. First, are these two compounds the same? Second, what are
their chemical formulas? And oh yes: do you know what was in the original
Calgon?
Thanks! Stuart Altmann
Gerry Barbe on sun 24 mar 96
On Sat, 23 Mar 1996, Stuart Altmann wrote:
> original-formula Calgon water softener (no longer available, apparently)
> was said to be an excellent deflocculant for glazes. I have seen two
> identifications of its composition. One is that it was tetrasodium
> pyrophosphate, the other, that it was sodium hexa-metaphosphate. So, two
> questions. First, are these two compounds the same? Second, what are
> their chemical formulas? And oh yes: do you know what was in the original
> Calgon?
Calgon was Sodium hexametaphosphate (NaPO3)6
tetrasodiumpyrophosphate would be Na4P2O7
Quick chemistry lesson. Phosphoric acid is H3PO4 so sodium phosphate is
Na3PO4 (aka TSP). Meta phosphoric acid is minus one water molecule (H2O)
or HPO3 so sodium metaphosphate is NaPO3 which is forms a hexamer (calgon)
and also a trimer. Pyro phosphoric acid is a dimer of the original
phosphoric acid minus one water molecule H4P2O7 so the sodium salt is
Na4P2O7.
Gerry Barbe - gbarbe@julian.uwo.ca
Dept. OB/GYN
University of Western Ontario
London, Ontario, CANADA
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