Why is [NiCl₄]²⁻ paramagnetic, and what is its electronic configuration?

[NiCl₄]²⁻ is paramagnetic due to the presence of two unpaired electrons in its electronic configuration. Nickel (Ni) in the +2 oxidation state has the electronic configuration 3d⁸. In the tetrahedral complex [NiCl₄]²⁻, one s orbital and three p orbitals of nickel undergo sp³ hybridization, forming four equivalent hybrid orbitals. Each chloride ion donates an electron pair for bonding. Despite the paired electrons from chloride ligands, two unpaired electrons remain in the hybrid orbitals, resulting in paramagnetism in the complex, as unpaired electrons contribute to magnetic moments.