 monoaddition or multiple additions and in case of multiple additions their topological relationships (new substituents huddled together or evenly spaced).In conformity with IUPAC rules, the terms methanofullerene are used to indicate the ring-closed (cyclopropane) fullerene derivatives, and fulleroid to ring-open (methanoannulene) structures.Fullerenes react as electrophiles with a host of nucleophiles in nucleophilic additions.