Carbon dioxide CO2 is a linear molecule with a central carbon atom and two oxygen atoms on either side. It has a total of 4n-5 = 3 vibrational modes where n is the number of atoms in the molecule since it is a linear molecule. These vibrational modes can be classified into two types: symmetric stretching and bending modes.1. Symmetric stretching mode 1 : In this mode, both oxygen atoms move away from or towards the central carbon atom simultaneously, either in phase or out of phase. The vibrational frequency for this mode is approximately 1330 cm^-1. This mode is not IR active because it does not result in a change in the dipole moment of the molecule.2. Bending mode 2 : In this mode, the molecule bends in a plane, with the angle between the oxygen atoms changing. The vibrational frequency for this mode is approximately 667 cm^-1. This mode is IR active and can be observed in the infrared spectrum.3. Asymmetric stretching mode 3 : In this mode, one oxygen atom moves away from the central carbon atom while the other moves towards it. The vibrational frequency for this mode is approximately 2349 cm^-1. This mode is IR active and can be observed in the infrared spectrum.In summary, the vibrational frequencies for CO2 are approximately 1330 cm^-1 symmetric stretching, not IR active , 667 cm^-1 bending, IR active , and 2349 cm^-1 asymmetric stretching, IR active . The infrared spectrum of CO2 will show two peaks corresponding to the bending and asymmetric stretching modes at 667 cm^-1 and 2349 cm^-1, respectively.