- The bond vibrations that can be observed in the IR spectrum of caffeine : 
 
i) asymmetric, ii) symmetric, iii) wagging, iv) twisting, v) scissoring, vi) rocking
- while the observable stretching frequencies are ; 1700, 1300, 2900, 1500 and 3000. 
 
Caffeine is a polyatomic molecule ( contains more than two atoms bonded via covalent bonds )  therefore its atoms can vibrate in three dimensions ( x, y, z ).therefore the bond vibrations that can be observed in the IR spectrum of caffeine are :  asymmetric, symmetric, wagging, twisting, scissoring, and rocking.
The observable stretching frequencies that are in the IR spectrum of caffeine ; C = O is 1700 ,  C - H is 1300,  C -H is 2900,  C -N is 1500, and N -H = 3000. 
Hence we can conclude The bond vibrations that can be observed in the IR spectrum of caffeine : i) asymmetric, ii) symmetric, iii) wagging, iv) twisting, v) scissoring, vi) rocking and the observable stretching frequencies are ; 1700, 1300, 2900, 1500 and 3000. 
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