Crystal Lattice Structures:	Reference Date:   1 Jan 2001
	Last Modified: 19 Dec 2008

The half-Heusler (C1_b) Structure

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• 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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• All of the atoms are located on the sites of a body centered cubic lattice. This is sometimes called the ``half-Heusler'' structure because it is identical to the L2₁ (Heusler) structure with half of the copper atoms missing.
• The Mg and Ag atoms form a rock salt (B1) structure, while the As and either the Mg or Ag atoms form a Zincblende (B3) structure.
• If the atoms on the (4a) and (4c) sites are identical, this reduces to the Fluorite (C1) structure.
• 17 Feb 2007: The Ag and As labels in the position files c1_b.pos and c1_b.xyz were reversed. These have been corrected. Also added a structure reference.

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• Prototype: AgAsMg or AlLiSi
• Pearson Symbol: cF12
• Strukturbericht Designation: C1_b
• Space Group: F43m (Cartesian and lattice coordinate listings available)
• Number: 216
• Reference: Pearson (Alloys), p. 386.
• Other Compounds with this Structure: MnNiSb, AuMgSn, CdLiP, BiMgNi, RhSnTi, numerous others.
• Primitive Vectors:

  A1	=	½ a Y + ½ a Z
  A2	=	½ a X + ½ a Z
  A3	=	½ a X + ½ a Y

• Basis Vectors:

  B1	=		0		(Mg)	(4a)
  B2	=	-½ A1 + ½ A2 + ½ A3	=	½ a X	(Ag)	(4b)
  B3	=	¼ A1 + ¼ A2 + ¼ A3	=	¼ a X + ¼ a Y + ¼ a Z	(As)	(4c)

See these vectors as LaTeX output (with a ==> 2 a).

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Structures indexed by: Strukturbericht Symbol Pearson Symbol Space Group Prototype

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