點解CO(一氧化碳)係共價鍵??

The type of covalent of CO is called a coordinate covalent bond, also known as dative bond. This is a description of covalent bonding in many kinds of compounds. The distinction from ordinary covalent bonding is artificial, but the terminology is popular in textbooks, especially those describing coordination compounds. Once the bonds have been formed using this, its strength and description is no different from that of other polar covalent bonds.

Coordinate covalent bonds are invoked when a Lewis base (an electron donor or giver) donates a pair of electrons to a Lewis acid (an electron acceptor) to give a so-called adduct. The process of forming a dative bond is called coordination. The electron donor acquires a positive formal charge, while the electron acceptor acquires a negative formal charge.

Classically, any compound that contains a lone pair of electrons is capable of forming a coordinate bond. The bonding in diverse chemical compounds can be described as coordinate covalent bonding.

• carbon monoxide (CO) can be viewed as containing one coordinate bond and two "normal" covalent bonds between the carbon atom and the oxygen atom. This highly unusual description illustrates the flexibility of this bonding description. Thus in CO, carbon is the electron acceptor and oxygen is the electron donor.

x x
C
x x o
o o o
O
o o

i.e.

C
III
O

呢個化合物係有共價鍵再加一個dative bond

C=O, 2個共價鍵之後再由O比多2粒電子(做多1個鍵令每邊8粒)

所以c同o之間有3個鍵