In article , George E. Cawthon says...

On sublimation of diamond. Although 3550 degree C is listed
as a melting point in several references some of the same
references indicate that it actually sublimes. Still, these
references don't fit what appears to be a valid reference
that says diamond breaks down at a much lower temp, and that
reference gave breakdown temps in the presence of oxygen and
in the presence of nitrogen. I believe that was in one of
Bob Powell's references.

At this point you are in the range of solid state chemistry.

I used to work with guys who 'did' solid state chemistry,
for things like crystaline lighting phospors, and for
ZrOx oxygen sensors. This was at GTE labs in waltham, mass.

Some of the guys had PhDs, and others simply worked in the
lab and wore those funny pointy hats with stars and plantets
on them. They also tended to have jars around with strange
labels, eye of newt and jaw of toad, etc. It's a very
strange discipline and most of it is art, to go along with
a small amount of science. Things like 'fluxes' that
work at 1600 deg C.

All I *can* say with some certainty is that a) one should not
attempt to intuit the results of an experiment based on
ordinary chemistry rules, and b) trust the experience of
those who have worked in the field.

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================