Crystal Lattice Structures:	Reference Date: 1 Jan 1997
	Last Modified: 13 Mar 2007

The Hexagonal Graphite (A9) Crystal Structure

You can now

see the structure from several perspectives;
examine the structure with an external viewer; or
download the coordinates of the atoms in these pictures in XYZ format.
visualize the structure (Uses the JMOL Applet)

This is a revised version of the original graphite structure phase. We have preserved the old graphite structure page here.
According to Wyckoff, hexagonal graphite may be either flat, space group P6₃/mmc (#194) or buckled, spage group P6₃mc (#186). If it is buckled, the buckling parameter is small, less than 1/20 of the ``c'' parameter of the hexagonal unit cell.
We will assign the A9 Strukturbericht Designation to the unbuckled structure, leaving a separate page for the Buckled (P6₃mc) graphite structure.
6 June 2006: Fixed exponents in Cartesian components of B₃ and B₄ basis vectors.
17 Feb 2007: Added C-for-Carbon labels to the basis vectors.

Experimentally, a

Rhombohedral (R3m) graphite structure is also observed.

Prototype: C (graphite)
Pearson Symbol: hP4
Strukturbericht Designation: A9
Space Group: P6₃/mmc (Cartesian and lattice coordinate listings available)
Number: 194
Reference: Wyckoff Vol I, p 26.
Other compunds with this structure: LiB

Primitive Vectors:

A₁	=	½ a X - ½ 3^1/2 a Y
A₂	=	½ a X + ½ 3^1/2 a Y
A₃	=	c Z

Basis Vectors:

B₁	=	¼ A₃	=	¼ c Z	(C)	(2b)
B₂	=	¾ A₃	=	¾ c Z	(C)	(2b)
B₃	=	1/3 A₁ + 2/3 A₂ + ¼ A₃	=	½ a X + ½ 3^-½ a Y + ¼ c Z	(C)	(2c)
B₄	=	2/3 A₁ + 1/3 A₂ + ¾ A₃	=	½ a X - ½ 3^-½ a Y + ¾ c Z	(C)	(2c)

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