Abstract
A new hydrocarbon - hydrographite - with the composition close to CH is shown to form from graphite and gaseous hydrogen at pressures above 2 GPa and temperatures from 450 to 700°C. Hydrographite is a black solid thermally stable under ambient conditions. If heated in vacuum, it decomposes into graphite and molecular hydrogen at temperatures from 500 to 650°C. Powder X-ray diffraction characterizes hydrographite as a multilayer "graphane II" phase predicted by ab initio calculations [Wen X-D et al. PNAS 2011; 108:6833] and consisting of graphane sheets in the chair conformation stacked along the hexagonal c axis in the -ABAB- sequence. The crystal structure of the synthesized phase belongs to the P63mc space group. The unit cell parameters are a = 2.53(1) Å and c = 9.54(1) Å and therefore exceed the corresponding parameters of graphite by 2.4(2)% and 42.0(3)%. Stretching vibrations of C-H groups on the surface of the hydrographite particles are examined by infrared spectroscopy.
| Original language | English |
|---|---|
| Pages (from-to) | 465-473 |
| Number of pages | 9 |
| Journal | Carbon |
| Volume | 100 |
| DOIs | |
| State | Published - Apr 1 2016 |
Funding
The work was supported by Grant No. 11-02-00401 from the Russian Foundation for Basic Research and by the Program “The Matter under High Pressure” of the Russian Academy of Sciences . A.I.K. greatly acknowledges the support from the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy .