Phosphorus Pentafluoride, having a chemical formula of PF5 is a colourless gas. The molecule has five single bonds between each Fluorine and Phosphorus atoms. This molecule is used for polymerization catalysts. To understand the polarity of this molecule one needs to know the shape and lewis structure, net dipole moment and the distribution of charges in this molecule.
The molecular geometry of this molecule is Trigonal Bipyramidal, which means two atoms of Fluorine are located in an axial position, and the other three are in the equatorial position. The arrangement of the atoms is quite symmetric for this molecule. Generally, the molecules having a symmetric distribution or arrangement are nonpolar in nature.
Net dipole moment in PF5
Phosphorus atoms has an electronegativity value of 2.19 and Fluorine’s electronegativity value is 3.98 The difference of electronegativities for both these atoms is quite higher than 0.4 which means that there can be a dipole moment in the molecule. But this dipole moment will be from the Phosphorus atom towards the Fluorine atom. All these dipole moments will be nullified because of the symmetric distribution of the atoms in the molecule. As a result, there is none or zero net dipole moment in PF5.
Distribution of charges in PF5
The molecules that have net dipole moment have regions of partial positive charges and partial negative charges. But here as the PF5 molecule doesn’t have any poles, the charges are distributed evenly in the molecule.
Is PF5 a polar or nonpolar molecule?
PF5 is a nonpolar molecule because there is no net dipole moment in the molecule. As the shape of the molecule is symmetric with even charge distribution, it makes Phosphorus Pentafluoride a nonpolar molecule.