why is calcium listed as paramagnetic even though it has no unpaired electron - Physics - Magnetism And Matter

Question

why is calcium listed as paramagnetic even though it has no
unpaired electron ??

Kumar Sarang · Accepted Answer

Now from electronic configuration its is seen that all electron are
paired up i e Ca should be diamagnetic The magnetic factor not only
depends on the electronic configuration but also depends on the
vacant orbital that are present next to valence orbital Now Ca
contain an empty d orbital whose energy is very close to valence s
orbital This presence of low lying vacant orbital near electrons of
4s orbital sometime cause transition of electron of 4s and
introduce the paramagnetic character by creating an unpaired
electron in s orbital and vacant d orbital This process occur due
to less energy difference outer s and d orbital

Secondly, due to above process their occur delocalization of
electron as electron tends to go to d orbital and come back to s
orbital again and again This allow Ca to have some amount of net
paramagnetic character
But mostly Ca in its ground state is diamagnetic

why is calcium listed as paramagnetic even though it has no unpaired electron ??