  This work demonstrates the effectiveness of the high-pressure method for the
production of graphite and diamond with a high degree of boron doping using
adamantanecarborane mixture as a precursor. At 8 GPa and $1700 ^{o}C$, graphite
is obtained from adamantane $C_{10}H_{16}$, whereas microcrystals of
boron-doped diamond (2{\div}2.5 at.% of boron) are synthesized from a mixture
of adamantane and ortho-carborane $C_{2}B_{10}H_{12}$ (atomic ratio B:C =
5:95). This result shows convincingly the catalytical activity of boron in the
synthesis of diamond under high pressure. At pressures lower than 7 GPa, only
graphite is synthesized from the adamantane and carborane mixture.
Graphitization starts at quite low temperatures (below $1400 ^{o}C$) and an
increase in temperature simultaneously increases boron content and the quality
of the graphite crystal lattice. Thorough study of the material structure
allows us to assume that the substitutional boron atoms are distributed
periodically and equidistantly from each other in the graphite layers at high
boron concentrations (>1 at.%). The theoretical arguments and model ab initio
calculations confirm this assumption and explain the experimentally observed
boron concentrations.
