DEAR JAUNEET,

It is stable only at low temperatures. When heated at temperature between 373 K and 575 K, it changes into higher boranes. The elements of group 13 have three electrons in their valence shell (ns²np^l) and, therefore, exhibit, oxidation state of + 3. However, it bas been observed that in addition to + 3 oxidation state, they also exhibit oxidation state of +1. The +1 oxidation state becomes more and more stable as one goes down the group from B, Al, Ga, In to Tl. The +1 oxidation state of Tl is more stable than +3 oxidation state. For e.g., thallous compounds such as TlOH and TlClO₄ are more stable than their thallic compounds. This is attributed to the inert pair effect. In the case of last element, after the removal of one electron from p-orbital, the remaining ns² (e.g. 6s²) electrons behave like stable noble gas and do not take part formation. This reluctance of the s-electron pair to take part in chemical combination is called inert pair effect. This helps to explain the stability of borane.

We are all IITians and here to help you in your IIT JEE preparation.

All the best.

 If you like this answer please approve it....

win exciting gifts by answering the questions on Discussion Forum