Kovalent Bağlar Kovalent Bağ nedir? - Kovalent bağ, bağ yapan iki atom arasında elektronların paylaşılması sonucunda oluşan kimyasal bir bağdır. - Bir kovalent bağ iki ametal arasında oluşur. Bir kovalent bağ nasıl oluşur?

Oksijen Molekülü(O 2 ) Kovalent Bağ: Elektronlar ortaklaşa kullanılır.

methane, CH 4 less repulsion between the bonding pairs of electrons 109.5° 90°

Are there atomic orbitals on C, Si, N and O to accommodate the bonding electrons of the shapes predicted by VSEPR? s orbital 3 p orbitals x y z x y z

x y z x y z Are there atomic orbitals on C, Si, N and O to accommodate the bonding electrons of the shapes predicted by VSEPR?

4 sp 3 orbitals x y z Are there atomic orbitals on C, Si, N and O to accommodate the bonding electrons of the shapes predicted by VSEPR?

4 sp 3 orbitals x y z C H H H H Are there atomic orbitals on C, Si, N and O to accommodate the bonding electrons of the shapes predicted by VSEPR?

Methane building blocks

2s2p x 2p z 2p y 1s sp 3 sp o Promote Hybridize x z y Methane: Carbon

hybrid orbitals – sp, sp 2, or sp 3 SİGMA (d) BAĞ OLUŞUMU

formation of  bond

Figure 11.9 The  bonds in ethane. both C are sp 3 hybridized s-sp 3 overlaps to  bonds sp 3 -sp 3 overlap to form a  bond relatively even distribution of electron density over all  bonds

NH 3 deki sp 3 hibrit orbitalleri Bağ açısı 107 o

H 2 O daki sp 3 hiprit orbitalleri Bağ açısı 105 o

The sp 2 hybrid orbitals in BF 3

BeCl 2 daki sp orbitalleri Atomik orbitaller hibrit orbitalleri Orbital Diyagramları

orbital diyagramları bağ açısı 180 o doğrusal

PCl 5 deki sp 3 d hibrit orbitalleri

PCl 5

3s3p x 3p z 3p y 2 Neon 120 o Hybridized Phosphorus Pentachloride: Phosphorus Trigonal Bipyrimidal sp 3 d sp 3 d sp 3 d sp 3 d sp 3 d d xz d yz d xy d x 2 -y 2 d z o 90 o Promoted

SF 6 deki sp 3 d 2 hiprit orbitalleri

remaining p orbitals from sp or sp 2  bond

formation of  bond Planar molecule (each carbon is trigonal planar) with  cloud above and below the plane  bond hinders rotation about the carbon-to- carbon bond

Figure The  and  bonds in ethylene (C 2 H 4 ) overlap in one position -  p overlap -  electron density

s + p x + p y = 3 sp 2 orbitals P z orbital

O C H H

C O H H

CH 2 O 120 o

2s2p x 2p z 2p y 1s sp 2 sp 2 sp o Hybridized Formaldehyde: Carbon Promoted 120 o Trigonal Planar 2s + 2p x + 2p z

2s2p x 2p z 2p y 1s sp 2 sp 2 sp o Hybridized Formaldehyde: Oxygen 120 o Trigonal Planar Lone Pairs 2s + 2p x + 2p z

Formaldehyde Sigma bond 2 Lone Pairs  bond

SP MELEZLEŞMESİ

Figure The  and  bonds in acetylene (C 2 H 2 ) overlap in one position -  p overlap - 

Multiple Bonds A double bond (2 pairs of shared electrons) consists of a sigma bond and a pi bond. A triple bond (3 pairs of shared electrons) consists of a sigma bond and two pi bonds. =>

s + p x = 2 sp orbitals P y orbital P z orbital

s + p x = 2 sp orbitals CN H

2s2p x 2p z 2p y 1s sp Promoted Hybridized Hydrogen Cyanide: Carbon 2s + 2p x Linear

2s2p x 2p z 2p y 1s sp Hybridized Hydrogen Cyanide: Nitrogen 2s + 2p x Linear

 bond

O 2 ve F 2 için O 2 paramanyetik

Atom numarası 3-7 arası moleküller için, (Li 2, Be 2, B 2, C 2 ve N 2 ) moleküler orbital enerji diyagramı C 2 nin diamanyetik olduğu elektronların bu düzendeki orbital diyagramına yerleştirilmesiyle anlaşılır.

Farklı İki Atom Arasındaki Molekküllerin Moleküller Orbitalleri Eğer molekülde oksijen varsa (CO gibi) aşağıdaki enerji diyagramı kullanılır.