Crystal Lattice Structures:	Creation Date: 13 Sep 2002
	Last Modified: 21 Oct 2004

The Hypothetical cF128 Ferrite 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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• Ferrite is steel with a bcc structure. This structure represents one possible ordering which might be found in an Fe-Ni-Cr steel. Note that it is not meant to represent a real steel.
• If we use the special values

  x1	=	1/8
  x2	=	1/4
  x3	=	38

  and replace the Ni atoms by Cr, then this structure reverts to CsCl (B2) with a_B2 = ¼ a. If we replace both the Ni and Cr atoms by Fe, then the structure becomes bcc, again with a_bcc = ¼ a.
• 18 July 2008: Corrected the Wyckoff positions of the Fe-II atoms.

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• Prototype: Cr₉Fe₁₆Ni₇ (hypothetical)
• Pearson Symbol: cF128
• Space Group: Fm3m (Cartesian and lattice coordinate listings available)
• Number: 225
• 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		(Cr-I)	(4a)
  B2	=	+ x1 A1 + x1 A2 + x1 A3	=	+ x1 a X + x1 a Y + x1 a Z	(Fe-I)	(32f)
  B3	=	+ 3 x1 A1 - x1 A2 - x1 A3	=	- x1 a X + x1 a Y + x1 a Z	(Fe-I)	(32f)
  B4	=	- x1 A1 + 3 x1 A2 - x1 A3	=	+ x1 a X - x1 a Y + x1 a Z	(Fe-I)	(32f)
  B5	=	- x1 A1 - x1 A2 + 3 x1 A3	=	+ x1 a X + x1 a Y - x1 a Z	(Fe-I)	(32f)
  B6	=	- x1 A1 - x1 A2 - x1 A3	=	- x1 a X - x1 a Y - x1 a Z	(Fe-I)	(32f)
  B7	=	- 3 x1 A1 + x1 A2 + x1 A3	=	+ x1 a X - x1 a Y - x1 a Z	(Fe-I)	(32f)
  B8	=	+ x1 A1 - 3 x1 A2 + x1 A3	=	- x1 a X + x1 a Y - x1 a Z	(Fe-I)	(32f)
  B9	=	+ x1 A1 + x1 A2 - 3 x1 A3	=	- x1 a X - x1 a Y + x1 a Z	(Fe-I)	(32f)
  B10	=	- x2 A1 + x2 A2 + x2 A3	=	+ x2 a X	(Ni-I)	(24e)
  B11	=	+ x2 A1 - x2 A2 + x2 A3	=	+ x2 a Y	(Ni-I)	(24e)
  B12	=	+ x2 A1 + x2 A2 - x2 A3	=	+ x2 a Z	(Ni-I)	(24e)
  B13	=	+ x2 A1 - x2 A2 - x2 A3	=	- x2 a X	(Ni-I)	(24e)
  B14	=	- x2 A1 + x2 A2 - x2 A3	=	- x2 a Y	(Ni-I)	(24e)
  B15	=	- x2 A1 - x2 A2 + x2 A3	=	- x2 a Z	(Ni-I)	(24e)
  B16	=	+ ½ A1	=	+ ¼ a Y + ¼ a Z	(Cr-II)	(24d)
  B17	=	+ ½ A2	=	+ ¼ a X + ¼ a Z	(Cr-II)	(24d)
  B18	=	+ ½ A3	=	+ ¼ a X + ¼ a Y	(Cr-II)	(24d)
  B19	=	- ½ A2 + ½ A3	=	+ ¼ a Y - ¼ a Z	(Cr-II)	(24d)
  B20	=	- ½ A1 + ½ A3	=	+ ¼ a X - ¼ a Z	(Cr-II)	(24d)
  B21	=	- ½ A1 + ½ A2	=	+ ¼ a X - ¼ a Y	(Cr-II)	(24d)
  B22	=	+ (x3 - 1) A1 + x3 A2 + x3 A3	=	+ x3 a X + (x3 - ½) a Y + (x3 - ½) a Z	(Fe-II)	(32f)
  B23	=	+ (3 x3 - 1) A1 - x3 A2 - x3 A3	=	- x3 a X + (x3 - ½) a Y + (x3 - ½) a Z	(Fe-II)	(32f)
  B24	=	- x3 A1 + (3 x3 - 1) A2 - x3 A3	=	+ (x3 - ½) a X - x3 a Y + (x3 - ½) a Z	(Fe-II)	(32f)
  B25	=	- x3 A1 - x3 A2 + (3 x3 - 1) A3	=	+ (x3 - ½) a X + (x3 - ½) a Y - x3 a Z	(Fe-II)	(32f)
  B26	=	- (x3 - 1) A1 - x3 A2 - x3 A3	=	- x3 a X - (x3 - ½) a Y - (x3 - ½) a Z	(Fe-II)	(32f)
  B27	=	- (3 x3 - 1) A1 + x3 A2 + x3 A3	=	+ x3 a X - (x3 - ½) a Y - (x3 - ½) a Z	(Fe-II)	(32f)
  B28	=	+ x3 A1 - (3 x3 - 1) A2 + x3 A3	=	- (x3 - ½) a X + x3 a Y - (x3 - ½) a Z	(Fe-II)	(32f)
  B29	=	+ x3 A1 + x3 A2 - (3 x3 - 1) A3	=	- (x3 - ½) a X - (x3 - ½) a Y + x3 a Z	(Fe-II)	(32f)
  B30	=	+ ¼ A1 + ¼ A2 + ¼ A3	=	+ ¼ a X + ¼ a Y + ¼ a Z	(Cr-III)	(8c)
  B31	=	- ¼ A1 - ¼ A2 - ¼ A3	=	- ¼ a X - ¼ a Y - ¼ a Z	(Cr-III)	(8c)
  B32	=	+ ½ A1 + ½ A2 + ½ A3	=	+ ½ a X + ½ a Y + ½ a Z	(Ni-II)	(4b)

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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).