Hybridization in Molecules Containing Double and Triple Bonds

Ha Hybridization in Molecules Containing Double and Triple Bonds 

Chemical Bonding II Molecular Geometry and Hybridization of Atomic Orbitals 

The following rule helps us predict hybridization in molecules containing multiple bonds If the central atom forms a double bond, it is ip -hybridized if it forms two double bonds or a triple bond, it is ip-hybridized. Note that this rule applies only to atoms of the second-period elements. Atoms of third-period elements and beyond that form multiple bonds present a more complicated picture and will not be dealt with here. 

(a) Top view showing the overlap of the sp orbitals between the C atoms and the overlap of the sp orbital with the 1s orbital between the C and H atoms. All the atoms lie along a straight line therefore, acetylene is a linear molecub. p) Side view showing the overlap of the two 2py orbitals and of the two 2pz orbitals of the two carbon atoms, which leads to the formation of two pi bonds, (c) Formation of the sigma and pi bonds as a result of the interactbns in (a) and p). (d) Electrostatic potential map of C 2- 

Describe the bonding in the fonnaldehyde molecule whose Lewis structure is 

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HYBRIDIZATION IN MOLECULES CONTAINING DOUBLE AND TRIPLE BONDS... 

Hybridization in Molecules Containing Double and Triple Bonds 337 Molecular Orbital Theory 340... 

The concept of valence bond theory and hybridization can also be used to describe the bonding in molecules containing double and triple bonds, such as ethylene (C2H4) and acetylene (C2H2). The Lewis structure of ethylene is... 

The hybridization concept can also be applied to molecules containing double and triple bonds. The descriptive valence bond approach to the bonding in ethylene and... 

The bonding pi orbital 71) follows regions separate from a line drawn between the two atoms in a bond. Two overlapping p orbitals will form n bonds to contain the additional shared electrons in molecules with double or triple bonds, n bonds prevent atoms from rotating about the central axis between them. The atomic orbitals that form the compound C2H4 are shown above to the left. Each H atom contains one electron in an s orbital and each C atom contains 4 valence electrons in three hybrid sp2 orbitals and one p orbital. The compound itself contains the molecular orbitals shown below to the left. There are five a bonds (white ovals) and one n bond (the shaded shapes). For additional examples of n bonds in carbon compounds, see Skill 6.1a. 

We now turn our attention to the application of VBT to double- and triple-bonded molecules. Taking molecular oxygen as an example, the Lewis structure for O2 contains an 0=0 double bond with two lone pairs of electrons on each of the O atoms. Thus, the electron geometry around each O is trigonal planar and the expected hybridization is sp based on the correlation listed in Table 10.2. 

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