Size-controllable synthesis of ultrasmall diamonds from halogenated adamantanes at high static pressure

We report on the use of dibromoadamantane C10H14Br2 as a promising precursor for the mass synthesis of ultrasmall diamonds at an industrially accessible pressure of 8 GPa. Under pressure, the formation of nanodiamonds upon decomposition of C10H14Br2 starts at the record low temperature of 1000 K. As a result of the decomposition, effective nucleation of diamonds and their slow growth at temperatures up to 2000 K provide favorable conditions for the size-controlled synthesis of nanodiamonds by changing the synthesis temperature. We show that chloroadamantane, C10H15Cl, is also a good candidate for producing nanodiamonds. (C) 2019 Elsevier Ltd. All rights reserved.