The chemical compound phosphorous pentachloride, which has the chemical formula PCl5, is a non-polar molecule. The molecular geometry of phosphorous pentachloride is symmetrical, which neutralizes the bond dipoles of the molecule to make it non-polar.
One way to characterize molecular compounds is by their polarity, which is a physical property of matter. Polarity influences a molecule's other physical attributes and is indicative of the quantity and kinds of covalent bonds that hold the compound together. The two types of covalent bonding that may occur in a molecular compound are polar and non-polar bonds. A polar bond is formed when the atoms comprising the molecule has an asymmetrical distribution of electrons in their bonds. This creates opposite partial charges, which when separated produce a dipole that results in a polar molecular compound. There are two categories of non-polar molecules: compounds with zero or nearly zero dipole moments and compounds with polar bonds but having a symmetrical molecular arrangement.
Phosphorous pentachloride is a highly reactive covalent chloride of the element phosphorous. The molecule has 40 valence electrons that are shared between one phosphorous atom and five chlorine atoms. The 10 electrons surrounding the central atom phosphorous, forms five bonds with the chlorine atoms. The electrons are arranged in a such a way that a symmetrical structure is produced. The molecular geometry of phosphorous pentachloride is trigonal bipyramidal. Although the covalent bonds created between phosphorous and chlorine are polar, the structure allows the dipoles to be cancelled out.