Crystal Lattice Structures:	Reference Date:   1 Jan 2001
	Last Modified: 21 Oct 2004

The αAs (A7) 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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• Note that when b = 0 and u = 1/8 this structure reduces to diamond. With b = 0 and u<>1/8 this lattice can be used to determine the Raman frequency of diamond crystals via the frozen phonon approximation.
• This is the same type of structure, obviously with different structural parameters, as the rhombohedral graphite and βO₂ structures, which we show in the rhombohedral orientation rather than the near cubic orientation used here.

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• Prototype: αAs
• Pearson Symbol: hR2
• Strukturbericht Designation: A7
• Space Group: R3m (Cartesian and lattice coordinate listings available)
• Number: 166
• Reference: Pearson (Alloys), p. 559.
• Other Elements with this Structure: Sb, Bi, rhombohedral graphite, βO₂
• Primitive Vectors:

  A1	=	b X + a Y + a Z
  A2	=	a X + b Y + a Z
  A3	=	a X + a Y + b Z

• Basis Vectors:

  B1	=	+ u (A1 + A2 + A3)	=	+ u (2 a + b) (X + Y + Z)	(As)	(2c)
  B2	=	- u (A1 + A2 + A3)	=	- u (2 a + b) (X + Y + Z)	(As)	(2c)

See these vectors in LaTeX output form.

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Structures indexed by: Strukturbericht Symbol Pearson Symbol Space Group Prototype

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