A monogranular or monolithic carbon material
with homogeneous microstructure which does not exhibit any structural components distinguishable by optical microscopy.
The above definition of a homogeneous microstructure does not pertain to pores and structural components which may be visible
by contrast differences in optical microscopy with polarized light. As a consequence, glass-like carbon
pores is still an agranular carbon. The same is true, for instance, for pyrolytic carbon
with preferred orientation, such as conical or lamellar structures, visible
in optical microscopy with polarized light. Use of the term agranular carbon is not restricted to bulk materials of a minimum size. Only particulate carbon
should be excluded even if the isolated particles exhibit a homogeneous microstructure.
PAC, 1995, 67, 473
(Recommended terminology for the description of carbon as a solid (IUPAC Recommendations 1995))
on page 476
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. doi:10.1351/goldbook