Steven Dutch, Professor Emeritus, Natural and Applied Sciences,
Universityof Wisconsin - Green Bay
To the right of each space group is a listing of coordinate points. These are thecoordinates to which a general point (x,y,z) is transformed by the space group. Origins(called "equivalent points" in the International Tables), areadditional points around which the points are transformed. For example, (0,0,0) refers toa corner of the unit cell, (1/2,1/2,1/2) to the center. All space groups have origin(0,0,0). For a space group with an additional origin (1/2,1/2,1/2), point (x,y,z) is alsotransformed to (1/2+x,1/2+y,1/2+z) and so on.
3-fold and 6-fold coordinates are tabulated with respect to axes intersecting at 60 degrees. In this oblique coordinate system, coordinates tend to be simple
183 P6mm (+x, +y, +z); (-y, +x-y,
+z); (+y-x, -x, +z); |
|
184 P6cc (+x, +y, +z); (-y, +x-y,
+z); (+y-x, -x, +z); |
|
185 P63cm (+x,
+y, +z); (-y, +x-y, +z); (+y-x, -x, +z); |
|
186 P63mc (+x,
+y, +z); (-y, +x-y, +z); (+y-x, -x, +z); |
|
187 P6*m2 (+x, +y, +z); (-y,
+x-y, +z); (+y-x, -x, +z); |
|
188 P6*c2 (+x, +y, +z); (-y,
+x-y, +z); (+y-x, -x, +z); |
|
189 P6*2m (+x, +y, +z);
(-y, +x-y, +z); (+y-x, -x, +z); |
|
189 P6*2c (+x, +y, +z); (-y,
+x-y, +z); (+y-x, -x, +z); |
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Created 30 March 1999, Last Update 11 June 2020