Improved crystallographic data for graphite

Powder diffraction pattern of SP-1 graphite has been obtained using synchrotron X-ray diffraction. Unit cell dimensions were calculated using a least-squares analysis that refined to a \Delta2thetadegrees\ of no more than 0.007. A hexagonal cell was determined with a space group of P6(3)/mmc (194), a=2.4617(2) and c=6.7106 (4) Angstrom. The Smith/Synder figure of merit is 167 based upon 11 peaks, which indicates that the quality of this data set is superior to the existing PDF card for graphite, 41-1487. It is also emphasized that the interlayer spacing of graphite should be 3.355(1) Angstrom. Using GAS and EXPGUI codes, a new set of calculated powder diffraction data based upon the interlayer spacing of 3.555 Angstrom is generated. A comparison with the current calculated card, 75-1621, has also been made. (C) 2003 International Centre for Diffraction Data.