c. Why do atomic orbitals need hybridization?Sp3Carbonhasfour valenceelectrons that are typically109.5°109.5°involved in the formation of 4C-H bonds.For a carbon atombonded tofourotheratoms,evidences109.5109.5°suggested that all of thebonds have similar bondingCH4orbitals.Hybrid Orbital Theory is phenomenological!
• Carbon has four valence electrons that are typically involved in the formation of 4 C-H bonds. CH4 c. Why do atomic orbitals need hybridization? Hybrid Orbital Theory is phenomenological! • For a carbon atom bonded to four other atoms, evidences suggested that all of the bonds have similar bonding orbitals
d.How doatomicorbitalshybridize?HybridizationofnAO'sof anatomgivesrisetonhybrid orbitals (HO)!nH(0A(i = ...n) →( - Zc,)(j = ...n)i=1e.g., a sp3-hybridized orbital can be expressed as:ph = C(02, + C2d2 px + Cgd2 py + C4d2 p2For equivalent hybridization, all n hybrid orbitals areequivalent in energy,but differ in directionality.Thecontributionof s orbital,if involved,toeachHOis equal
• Hybridization of n AO’s of an atom gives rise to n hybrid orbitals (HO)! d. How do atomic orbitals hybridize? h s px py pz c c c c 1 2 2 2 3 2 4 2 (i ,.,n ) c ( j ,.,n ) A O i n i j i H O j A O { i } 1 { } 1 1 e.g., a sp3 -hybridized orbital can be expressed as: • For equivalent hybridization, all n hybrid orbitals are equivalent in energy, but differ in directionality. The contribution of s orbital, if involved, to each HO is equal
2.Construction of hybrid orbitalsa. sp hybridizationb. sp? hybridizationc. sp hybridizationd. dsp3 (sp'd) hybridization (trigonal bipyramidal orsquarepyramidal)e. dsp? (sp-d) hybridization (square planar)f. d?sp3 (sp'd2)hybridization (octahedral)g. More ... (e.g., sp'd3f, or sp'd3)F= /21+1Bonding ability ofAO:=1,F, = V3,F = V5..FS
2. Construction of hybrid orbitals a. sp hybridization b. sp2 hybridization c. sp3 hybridization d. dsp3 (sp3d) hybridization (trigonal bipyramidal or square pyramidal) e. dsp2 (sp2d) hybridization (square planar) f. d 2 sp3 (sp3d 2 )hybridization (octahedral) g. More . (e.g., sp3d 3 f, or sp3d 3 ) Bonding ability of AO: F 2l 1 F 1,F 3,F 5. s p d
a. sphybridization (linearspecies)One s and one p AO's mix to form a set of two hybrid orbitals+x2pxsp HOi2s01X2pxsp HO22s Accordingly, equivalent sp-hybridization results in two hybrids:+ΦDLDs - d2 px)s-character2Each having 50% contribution from s orbital: α = Ic2s/2=l/2i)Normalization and orthogonalityph,hidt=S,ii) Linearly aligned with a bond angle θ=180°
a. sp hybridization (linear species) • One s and one p AOs mix to form a set of two hybrid orbitals. ( ) h1 2s 2 px 2 1 hjhid ij • Accordingly, equivalent sp-hybridization results in two hybrids: ( ) h2 2s 2 px 2 1 i) Each having 50% contribution from s orbital: = |c2s| 2=1/2. iii) Linearly aligned with a bond angle = 180. ii) Normalization and orthogonality: s-character
Equivalent /inequivalent sp-hybridizationWhether an atom adopts equivalent or inequivalenthybridization depends on its chemical environmentsp-hybridization at Be atomequivalentCl-Be-ClinequivalentCl-Be-Br
Equivalent /inequivalent sp-hybridization Cl-Be-Cl Whether an atom adopts equivalent or inequivalent hybridization depends on its chemical environment! Cl-Be-Br sp-hybridization at Be atom inequivalent equivalent