What is the difference between paramagnetic and diamagnetic compounds?

Paramagnetic compounds are attracted to magnetic fields due to unpaired electrons, while diamagnetic compounds are repelled due to paired electrons.

Paramagnetic and diamagnetic compounds exhibit different behaviours when exposed to a magnetic field due to the arrangement of their electrons. In paramagnetic compounds, one or more unpaired electrons are present in the atomic or molecular orbitals. These unpaired electrons have magnetic moments that align with the magnetic field, causing the compound to be attracted towards it. This property is temperature dependent, as the alignment of the magnetic moments can be disrupted by thermal agitation. Examples of paramagnetic compounds include oxygen and iron(III) chloride.

On the other hand, diamagnetic compounds have all their electrons paired in atomic or molecular orbitals. These paired electrons have opposing magnetic moments that cancel each other out, resulting in no net magnetic moment. When a magnetic field is applied, a slight magnetic moment is induced in the opposite direction, causing the compound to be repelled from the magnetic field. This property is not temperature dependent, as the paired nature of the electrons is not affected by thermal agitation. Examples of diamagnetic compounds include water and sodium chloride.

The difference between paramagnetic and diamagnetic compounds can be determined using experimental techniques such as the Gouy balance method or the Faraday method. These techniques involve measuring the change in weight or the change in magnetic susceptibility of a sample when a magnetic field is applied. The results can then be used to identify whether a compound is paramagnetic or diamagnetic.

In summary, the key difference between paramagnetic and diamagnetic compounds lies in their electron configuration and their behaviour in a magnetic field. Paramagnetic compounds, with their unpaired electrons, are attracted to magnetic fields, while diamagnetic compounds, with their paired electrons, are repelled. This fundamental difference has significant implications in various fields of chemistry, including inorganic chemistry, physical chemistry, and materials science.