Enumerations for _Chem_comp_atom.Chirality (A closed enumeration)
`E` | '(E)- alkene (German, entgegen = opposite)'
`N` | 'atom is not a chiral center'
`pro-R` | 'If substituted for a higher molecular weight entity will make the attached atom an R chiral center'
`pro-S` | 'If substituted for a higher molecular weight entity will make the attached atom an S chiral center'
`R` | 'rectus - right handed configuration'
`S` | 'sinister - left handed configuration'
`Z` | '(Z)- alkene (German, zusammen = together)'