Catenation by Ali Afzal.pptx

To Understand what Catenation is .

1. By ALI AFZAL Catenation 1

2. Catenation Catenation is  the ability of carbon to form long chains . In fact, carbon atoms are unique because of catenation—they are unique among all of the other atoms found in nature. Now, carbon chains are formed because they form bonds, or tetravalent bonds, with other carbon atoms. 2

3. Cont…. Examples :   Carbon is the most common element that exhibits catenation. It can form long hydrocarbon chains and rings like benzene. 3

4. Cont… 4

5. Carbon Catenation occurs most readily with carbon, which forms covalent bonds with other carbon atoms to form longer chains and structures. This is the reason for the presence of the vast number of organic compounds in nature.  Carbon is most well known for its properties of catenation, with organic chemistry essentially being the study of catenated carbon structures (and known as  catenae ). 5

6. Catenation property . When two or more atoms of an element combine with each other through the covalently single bond, double bond or triple bond to form a long chain structure, then that characteristic of the elements is called  catenation   property . 6

7. Cont…. 7

8. Cont… When a large number of carbon atoms are  covalently bonded with each other through the single bond, double bond or triple bond, resulting in the formation of a large number of cyclic or open chain compounds, so in the case of carbon this properties is called  catenation   property  of carbon. 8

9. Carbon Shows Highest Degree Of Catenation The ionization potential of carbon is quite high and its electron affinity is of moderate quality. The  size of carbon  atom is small. Now, it has been experimentally found that the carbon atom shows highest degree of  catenation . Observations have shown that there are three main reasons for showing of  catenation   property  by carbon atom. (I)The C — C bond energy is higher than their expected value due to small size of carbon atom. 9

10. Cont… ( II)Carbon shows tetravalency and forms large number of covalent bonds. (III)Carbon occupied less diffused atomic orbital due to small atomic size and hence a strong overlapping occurs among the orbitals . (II)Carbon shows tetravalency and forms large number of covalent bonds . The End … 10