Question

a) The shape of PCl5 is trigonal bipyramidal but of ClF3 is ‘T’ shaped, although in both

molecules central atom has sp3

d hybridization, explain.​

Answer 1

In PCL5 there is no lone pair present

but in case of CIF3 two lone pair are present which change the shape of molecule in T form...shape is change due to repulsion

Answer 2

Answer:

$PCl_{5}$ takes the trigonal bipyramidal shape as there are no lone pair of electrons present in this case, so there is no repulsion between the lone pair of electrons and bond pairs.
On the other hand, $ClF_{3}$ takes a T-shaped structure since 2 lone pairs of electrons are present which repel each other and push the other bonded atoms to another side

Explanation:

What is Hybridization?

Hybridization is a concept in which different atomic orbitals having almost the same energies mix together, which is followed by separation to form a completely new type of orbital.
The new type of orbital formed is known as the hybrid orbital.

How many types of hybridized orbital are seen?

Generally, 6 types of hybrid orbitals are seen:

Orbital needed                                                     Hybridization

          2                                                                         sp

          3                                                                         sp²

          4                                                                         sp³

          5                                                                         sp³d

          6                                                                         sp³d²

          7                                                                         sp³d³

The formula for calculation hybridization of any molecule:

Many formulas and tricks are there to determine the hybridization of a molecule or atom. Yet, the simplest formula is:

Hybridization= Total number of sigma bonds + lone pairs

Case of sp³d orbital hybridization:

For the sp³d type of hybridization, 5 distinct orbitals are needed, which can occur in the following combination (see the chart attached to understand the shape in each case)

Hybridization           sigma-bond             lone pairs                Shape

                                         5                             0                    Trigonal
                                                                                               Bipyramidal

      sp³d                            4                             1                      K-shaped
                                                                                                 (see-saw)

                                          3                             2                     T-shaped

                                          2                             3                      Linear

Case of $PCl_{5}$:

In $PCl_{5}$, the central atom is phosphorus. P contains 5 electrons in its outermost cell and it is bounded with 5 respective Cl atoms. It contains no lone pairs. Thus, it takes the trigonal bipyramidal shape.

Case of $ClF_{3}$:

In $ClF_{3}$, the central atom is chlorine. Cl contains 7 electrons in its outermost cell. Out of the seven electrons, 3 are shared with fluorine atoms. Thus, two lone pairs remain.
Thus, it takes the T-shaped.
This resultant shape is due to the combined effect of lone pair-lone pair repulsion, lone pair-bond pair repulsion, and, bond pair-bond pair repulsion according to VSEPR theory.

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