Structural considerations based on chemical bond strength allow us to predict the nature and the number of bond versus X. Application of the Anderson concept of electron pairing to dangling bonds leads to polar states. We predict the nature and the number of such polar states versus X. This mode is tested by studying the variation of the Urbach tail with temperature and composition. The Urbach tail comes from internal microfield, arising, here, from polar states and optical phonons of the Ge‐Te bonds. The qualitative variations of their number with X can be deduced from experiments. They are in agreement with the postulated model of electron pairing.