sentences:  Specifically, symmetry operation column headers 2S8 and 2S83 were reversed in the older references.The antiprismatic groups are denoted by "D"nd.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) "n" mirror planes "σd" which contain "C"n. The "D"1"d" group is the same as the "C"2"h" group in the reflection groups section.