Here are the data structures with brief descriptions:

Casdf_options
Ccrystal_refls
Cdetgeom
Cdetgeom_panel
Cdetgeom_panel_group
Cdg_group_info
Cfelix_options
Cfom_rejections
Cfom_shells
Cfromfile_options
Cg6
Cgaussian
Cheader_cache_entry
Cimage
Cimagefeature
Cpeak_params
Cpf8_private_data
Cpinkindexer_options
Cpolarisation
Cquaternion
CRational
Creflection_contributions
Creflpeak
Crvec
Ctaketwo_options
Cxgandalf_options