Round 3: Tossup 9

Hydrosilanes exchange these entities when reacted with metal alkyls in a reaction observed in lutetium methyl complexes by Patricia Watson. Whether these entities interchange or migrate to new sites differentiates type I and type II of one reaction class. Two of these entities are either (-5[1])added or removed (-5[1])at one atom in (15[1])cheletropic reactions. Platinum chloride complexes (*) “activate” these entities in the Shilov system. (10[1])Woodward-Hoffmann notation uses an order term in square brackets denoting the shift in these entities in a namesake type of pericyclic reaction. In a (-5[1])namesake rule, the number of these bonds in a molecule equals the number of atoms plus the number of rings minus one. For 10 points, name these covalent bonds formed by overlapping orbitals, which in double bonds exist alongside a pi-bond. ■END■ (10[3])

ANSWER: sigma bonds [accept single bonds or C-H bonds or carbon-hydrogen bonds or C-C bonds or carbon-carbon bonds; prompt on covalent bonds] (The first two lines refer to sigma bond metathesis and dyotropic reactions respectively.)
<MS, Chemistry> | NAFTA-Packet-3
= Average correct buzzpoint

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