Answer to Question #22156 in Organic Chemistry for naeim vhora

Question

C-O bond length in HCO2- is not longer than C-O bond length in CO3(2-) &
C-O bond length in HCO2- is and C-O bond length in CO3(2-) are not equal.how?

Answer 1

When we draw the lewis structure for (CO3)2-& ion, we get a double bond between one oxygen and the carbon, with single bonds between the other two oxygen atoms and the carbon. Because each of the oxygens want a double bond to the carbon, they all fight over it (giving resonance structures), meaning that in the end, you get a bond something between a double and a single bond for each Carbon-Oxygen bond. Therefore, this bond will be longer than a single bond, but shorter than a double bond. In (HCO2)- one of the oxygen has single bond with H, so in this case only two Carbon-Oxygen bond are something between a double and a single bond,and that will has different& length than the same atoms in [CO3]2- .