Data type: numb (with optional s.u. in parentheses)
Must appear in a looped list containing '_geom_hbond_atom_site_label_'
Units: deg ( degrees)
Angle in degrees defined by the three sites _geom_hbond_atom_site_label_D, *_H and *_A. Site at *_D (the hydrogen atom participating in the interaction) is at the apex of the angle.