Question

The number of species from the following which have square pyramidal structure is___
\(PF_5, BrF^− _4 4 − , IF_5\) ; \(BrF_5, XeOF_4, ICl ^−_ 4\)

Answer 1

Correct Answer: 3

To determine which species have a square pyramidal structure, we analyze each compound based on its electron geometry and molecular geometry. The square pyramidal shape typically corresponds to a central atom with an \(\text{sp}^3\text{d}^2\) hybridization and one lone pair.

1. \(PF_5\): Phosphorus pentafluoride has a trigonal bipyramidal structure with \(\text{sp}^3\text{d}\) hybridization. No lone pairs are present. Not square pyramidal.

2. \(BrF_4^-\): Bromine with 7 valence electrons, plus 1 from the negative charge, makes 8. Subtracting 4 bonding pairs, we have 2 lone pairs. The shape is square planar with \(\text{sp}^3\text{d}^2\) hybridization. Not square pyramidal.

3. \(IF_5\): Iodine with 7 valence electrons forms 5 bonds with fluorine, leaving 1 lone pair. The structure is square pyramidal with \(\text{sp}^3\text{d}^2\) hybridization. Square pyramidal.

4. \(BrF_5\): Bromine with 7 valence electrons forms 5 bonds and has 1 lone pair. This results in a square pyramidal structure with \(\text{sp}^3\text{d}^2\) hybridization. Square pyramidal.

5. \(XeOF_4\): Xenon has 8 valence electrons, forms 5 bonds, and contains 1 lone pair, leading to a square pyramidal geometry with \(\text{sp}^3\text{d}^2\) hybridization. Square pyramidal.

6. \(ICl_4^-\): Iodine with 7 valence electrons, plus 1 from the negative charge, totals 8. With 4 bonding pairs and 2 lone pairs, it forms a square planar geometry. Not square pyramidal.

The species with square pyramidal structures are \(IF_5\), \(BrF_5\), and \(XeOF_4\). Thus, the number of such species is 3, which matches the given range of 3 to 3.