Crystal Lattice Structures:	Creation Date: 17 April 2002
	Last Modified: 21 Oct 2004

The Esseneite 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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• According to the American Mineralogist Crystal Structure Database, the actual structure of this mineral, described in M. A. Cosca and D. R. Peacor, American Mineralogist 72, 148 (1987), is

  (Ca_0.97Fe_0.03) (Fe_0.58Al_0.42) O₆ (Si_0.54Al_0.46)₂

  For our purposes, we'll use the majority atom at each site to label the site.

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• Prototype: CaFeO₆Si₂
• Pearson Symbol: mC40
• Space Group: B2/b (Cartesian and lattice coordinate listings available)
• Number: 15
• Primitive Vectors:

  A1	=	½ a X - ½ b Y
  A2	=	½ a X + ½ b Y
  A3	=	c cos(β) X + c sin(β) Z

• Basis Vectors:

  B1	=	- y1 A1 + y1 A2 + ¼ A3	=	+ ¼ c cos(β) X + b y1 Y + ¼ c sin(β) Z	(Ca)	(4e)
  B2	=	+ y1 A1 - y1 A2 + ¾ A3	=	+ ¾ c cos(β) X - b y1 Y + ¾ c sin(β) Z	(Ca)	(4e)
  B3	=	- y2 A1 + y2 A2 + ¼ A3	=	+ ¼ c cos(β) X + b y2 Y + ¼ c sin(β) Z	(Fe)	(4e)
  B4	=	+ y2 A1 - y2 A2 + ¾ A3	=	+ ¾ c cos(β) X - b y2 Y + ¾ c sin(β) Z	(Fe)	(4e)
  B5	=	+ (x3 - y3) A1 + (x3 + y3) A2 + z3 A3	=	+ [a x3 + c z3 cos(β)] X + b y3 Y + c z3 sin(β) Z	(O-I)	(8f)
  B6	=	- (x3 + y3) A1 + (y3 - x3) A2 + (½ - z3) A3	=	- [a x3 - c (½ - z3) cos(β)] X + b y3 Y + c (½ - z3) sin(β) Z	(O-I)	(8f)
  B7	=	+ (y3 - x3) A1 - (x3 + y3) A2 - z3 A3	=	- [a x3 + c z3 cos(β)] X - b y3 Y - c z3 sin(β) Z	(O-I)	(8f)
  B8	=	+ (x3 + y3) A1 + (x3 - y3) A2 - (½ - z3) A3	=	+ [a x3 - c (½ - z3) cos(β)] X - b y3Y - c (½ - z3)sin(β) Z	(O-I)	(8f)
  B9	=	+ (x4 - y4) A1 + (x4 + y4) A2 + z4 A3	=	+ [a x4 + c z4 cos(β)] X + b y4 Y + c z4 sin(β) Z	(O-II)	(8f)
  B10	=	- (x4 + y4) A1 + (y4 - x4) A2 + (½ - z4) A3	=	- [a x4 - c (½ - z4) cos(β)] X + b y4 Y + c (½ - z4) sin(β) Z	(O-II)	(8f)
  B11	=	+ (y4 - x4) A1 - (x4 + y4) A2 - z4 A3	=	- [a x4 + c z4 cos(β)] X - b y4 Y - c z4 sin(β) Z	(O-II)	(8f)
  B12	=	+ (x4 + y4) A1 + (x4 - y4) A2 - (½ - z4) A3	=	+ [a x4 - c (½ - z4) cos(β)] X - b y4 Y - c (½ - z4) sin(β) Z	(O-II)	(8f)
  B13	=	+ (x5 - y5) A1 + (x5 + y5) A2 + z5 A3	=	+ [a x5 + c z5 cos(β)] X + b y5 Y + c z5 sin(β) Z	(O-III)	(8f)
  B14	=	- (x5 + y5) A1 + (y5 - x5) A2 + (½ - z5) A3	=	- [a x5 - c (½ - z5) cos(β)] X + b y5 Y + c (½ - z5) sin(β) Z	(O-III)	(8f)
  B15	=	+ (y5 - x5) A1 - (x5 + y5) A2 - z5 A3	=	- [a x5 + c z5 cos(β)] X - b y5 Y - c z5 sin(β) Z	(O-III)	(8f)
  B16	=	+ (x5 + y5) A1 + (x5 - y5) A2 - (½ - z5) A3	=	+ [a x5 - c (½ - z5) cos(β)] X - b y5 Y - c (½ - z5) sin(β) Z	(O-III)	(8f)
  B17	=	+ (x6 - y6) A1 + (x6 + y6) A2 + z6 A3	=	+ [a x6 + c z6 cos(β)] X + b y6 Y + c z6 sin(β) Z	(Si)	(8f)
  B18	=	- (x6 + y6) A1 + (y6 - x6) A2 + (½ - z6) A3	=	- [a x6 - c (½ - z6) cos(β)] X + b y6 Y + c (½ - z6) sin(β) Z	(Si)	(8f)
  B19	=	+ (y6 - x6) A1 - (x6 + y6) A2 - z6 A3	=	- [a x6 + c z6 cos(β)] X - b y6 Y - c z6 sin(β) Z	(Si)	(8f)
  B20	=	+ (x6 + y6) A1 + (x6 - y6) A2 - (½ - z6) A3	=	+ [a x6 - c (½ - z6) cos(β)] X - b y6 Y - c (½ - z6) sin(β)Z	(Si)	(8f)

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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).