<http://schema.org/position>
"1"^^<http://www.w3.org/2001/XMLSchema#integer>
<http://chemwiki.ucdavis.edu/Organic_Chemistry/Alkyl_Halides/Properties_of_Alkyl_Halides/Haloalkanes/Alkyl_Halide_Reactions/Substitution_and_Elimination_Reactions_of_Alkyl_Halides/SN1_Substitution_Reactions/Steric_Hindrance_to_Rear-side_Approach_in_Nucleophilic_Substitution>