Old way of Space group determination: Difference between revisions

Old way of Space group determination (view source)

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 ** for many Bravais types (defined at [http://www.iucr.org/iucr-top/cif/cifdic_html/2/cif_sym.dic/Ispace_group.Bravais_type.html]), there are several possible point groups (tp and tI: 4, 422; hP: 3, 6, 312, 321, 622; hR: 3, 32; cP, cF and cI: 23 and 432) and thus several possible space groups. In these cases, each point group has to be tested: the SPACE_GROUP_NUMBER has to be changed to one of those consistent with the point group, and the CORRECT step re-run.
 * repeat for each possible lattice character
-* finally decide on the correct Bravais lattice and point group by comparing R-factors (in particular R_meas), and, from there, come up with possible space groups by looking at the table of systematic absences along the h,0,0 0,k,0 and 0,0,l axes of the diffraction pattern.
+* finally decide on the correct Bravais lattice and point group by comparing R-factors (in particular R<sub>meas</sub>), and, from there, come up with possible space groups by looking at the table of systematic absences along the h,0,0 0,k,0 and 0,0,l axes of the diffraction pattern.
 Be aware of the possibility of [http://www.ccp4.ac.uk/dist/html/twinning.html twinning], and of the different, but equivalent ways to index a given diffraction pattern ([[reindexing]])!