Alkynes structure and bonding

PROBLEM 3.21 Draw the other form of bicyclo[3.3.1]non-l-ene (Z or ). Why is it less stable than the one in Rgure 3.47 Hint Focus on the rings in which the double bonds are contained. 

There is little difference in physical properties between the alkenes and their saturated relatives, the alkanes. The odors of the alkenes are a bit more pungent and perhaps justify being called evU-smelling. Tn fact, the old trivial name for alkenes, olefins, readily evokes the sense of smell. Tables 3.2 and 3.3 list some data for alkenes and cycloalkenes. 

We can anticipate that these new sp hybrids will be directed so as to keep the bonds, and the electrons in them, as far apart as possible, which produces 180° angles (Fig. 3.48). (Recall our discussion of BeH2, p. 53.) 

FIGURE 3.49 An j -hybridized carbon atom. Note the leftover, unhybridized 2py and 2p orbitals. 

FIGURE 3.48 To make an hybrid we combine the wave functions for the carbon 2s and 2px orbitals. The 2py and 2p orbitals are not used in the hybridization scheme. 

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Derivatives and Isomers of Alkenes Nomenclature The Cahn-Ingold-Prelog Priority System Relative Stability of Alkenes Heats of Formation Double Bonds in Rings Physical Properties of Alkenes Alkynes Structure and Bonding... 

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