Question

why TeCl4 is more stable than SCl4 and SeCl4​

Answer 1

Structural and conformational properties of the tetrahalides MX

4

with M = S,Se,Teand X =F,Cl,Br, I were studied with quantum chemical calculations (MP2/aug-cc-pVTZ and relativistic core potentials for heavy atoms). The pseudotrigonal bipyramidal geometries (C

2v

symmetry) of the three tetrafluorides and ofTeCl

4

, whose structures have been determined by gaselectron diffraction, are very well reproduced with this computational method. No additional stable conformer withC

3v

,C

S

,C

4v

orT

d

symmetry is predicted for these fourchalcogentetrahalides. For all other MX

4

compounds, except SeI

4

, the existence of two conformers withC

2v

andT

d

symmetry is predicted. TheT

d

structure is favoured in the case of SI

4

andSeBr

4

and SeI

4

is predicted to exist only asT

d

conformer.

Thank You

B.K.R