hexagonal graphite

The thermodynamically @S05900@ form of @G02684@ with an ABAB stacking @ST06775@ of the @G02683@. The exact crystallographic description of this allotropic form is given by the space group \(d_{6h}^{4} - P6_{3}/\text{mmc}\) (@U06562@ constants: \(a=245.6\ \mathrm{pm}\), \(c=670.8\ \mathrm{pm}\)). Hexagonal @G02684@ is thermodynamically @S05900@ below approximately \(2600\ \text{K}\) and \(6\ \text{GPa}\).
The use of the term @G02684@ instead of the more exact term hexagonal @G02684@ may be tolerated in view of the minor importance of @R05385@, the other allotropic form.
PAC, 1995, 67, 473. (Recommended terminology for the description of carbon as a solid (IUPAC Recommendations 1995)) on page 494 [Terms] [Paper]