sentences:  These groups are characterized by i) an "n"-fold proper rotation axis "C"n; ii) "n" 2-fold proper rotation axes "C"2 normal to "C"n; iii) a mirror plane "σh" normal to "C"n and containing the "C"2s.The "D"1"h" group is the same as the "C"2"v" group in the pyramidal groups section.The D8"h" table reflects the 2007 discovery of errors in older references.