We report on the possible synthesis of the theoretically predicted P-phase
of carbon nitride (C3N4) by shock compression of sodium dicyanamide mixed w
ith sodium azide and carbon tetra-iodide. Shock-compression experiments wer
e performed on starting precursor blended with similar to 95 wt.% Cu powder
, statically pressed in steel capsules. The capsules were impacted under co
nditions of constant shock amplitude, but varying shock-pulse duration. TEM
analysis of the recovered shock compressed residue showed crystallites of
a cubic C-N compound dispersed in an amorphous matrix, with overall yield o
f the crystalline phase being a function of the shock-pulse duration. Paral
lel-detection electron energy loss spectroscopy of the nitrogen-containing
crystallites revealed diamond-like sp(3) bonding. Infra-red spectroscopy in
dicated absorption lines in regions calculated to be appropriate for beta -
C3N4. (C) 2001 Elsevier Science Ltd. All rights reserved.