Crystal Lattice Structures:	Creation Date: 20 Apr 2002
	Last Modified: 21 Oct 2004

The Rhombohedral Graphite 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)

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• This is a part of a revised version of the original graphite structure phase. We have preserved the old graphite structure page here.
• Graphite also comes in a hexagonal form, either flat (A9) or buckled
• Note that this structure has the same symmetry and Wyckoff positions as the arsenic (A7) structure (though we have shown that in a different orientation) and βO₂.
• When z = 1/6 (shown in the figures above) we have smooth graphite sheets. Other values of z lead to buckling
• When θ = 60 degrees and z = 1/8 we get the diamond (A4) structure.
• The rhombohedral lattice can be specified by the length of the primitive vectors, a, and the angle between them, θ, or by the lattice constants of the equivalent hexagonal lattice. In terms of a and θ we have
  
  a_hex = 2 a sin(½ θ)
  
  c_hex = a {3 [1 + 2 cos(θ)]}^½

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• Prototype: C (rhombohedral graphite)
• Pearson Symbol: hR2
• Space Group: R3m (Cartesian and lattice coordinate listings available)
• Number: 166
• Reference: Wyckoff Vol I, p 27.
• Primitive Vectors:

  A1	=	+ ahex/2 X - ahex/(2 31/2) Y + chex/3 Z
  A2	=	+ ahex/31/2 Y + chex/3 Z
  A3	=	- ahex/2 X - ahex/(2 31/2) Y + chex/3 Z

• Basis Vectors:

  B1	=	+ z (A1 + A2 + A3)	=	+ z chex Z	(C)	(2c)
  B2	=	- z (A1 + A2 + A3)	=	- z chex Z	(C)	(2c)

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Structures indexed by: Strukturbericht Symbol Pearson Symbol Space Group Prototype

This is a mirror of an old page created at the Naval Research Laboratory Center for Computational Materials Science The maintained successor is hosted at http://www.aflowlib.org/CrystalDatabase/ and published as M. Mehl et al., Comput. Mater. Sci. 136 (Supp.), S1-S828 (2017).