When using DFT:

(1) Accurate result: def2-TZVP

(2) Good result: lanl08(d)

(3) Acceptable result: lanl2DZ

PS: Don't for get to use diffuse function when needed.

For tellurium compounds the most appropiate basis set are def family basis.

Note: Use ECP also

Thanks  Tian Lu sir and Jyotirmoy Deb sir i wiil try to use these basisi set

•  For tellurium compounds thé most appropiate bais set are 6-31**

You could try one of the  Ahlrichs basis sets  ( for example: def2-TZVPP) with effective core potential ECP to speed up your calculation.

Thank you for your kind response

Thanks Houria Djeradi mam and Norah O. A. Al-Otaibi sir.

i appreciate your suggestion and use it