Question

Why are lithium compounds covalent in nature?

Answer 1

Lithium is a chemical element with the atomic number 3 and the symbol Li. It's a silvery-white alkali metal that's pleasant to the touch. It is the lightest metal and the lightest solid element under normal circumstances. Lithium, like all alkali metals, is very reactive and combustible, thus it must be kept in a vacuum, inert environment, or inert liquid like refined kerosene or mineral oil.

Complete answer:
Although we know that ionic compounds with cation and anion are considered ionic and have ionic character, there are certain ionic compounds that have a covalent character. Fajan's rule determines the ionic bond's partly covalent nature. When oppositely charged ions are brought together, the binding nature between them is determined by the influence of one ion on the other ion, according to Fajan's rule. When two oppositely charged ions approach one other, the positively charged ion attracts the electrons in the anion's outermost shell and repels the positive-charged nucleus.
Anion polarisation or distortion results as a result of this. Ionic bonds are created when the polarisation is minimal, while covalent bonds are formed when the polarisation is significant.
Because lithium is such a tiny ion, it can polarise or distort the anion electron cloud. As a result, the lithium halide is partially covalent. Large-sized anions can quickly become polarised. Because lithium is the smallest element in group 1, the attraction between the outer electrons and the nucleus is stronger in lithium compounds. As a result, it is extremely difficult for it to lose electrons to another element in order to create a compound by an ionic connection.

Note:
Polarization power refers to the cation's capacity to distort the anion, whereas polarizability refers to the anion's ability to be distorted by the cation. When two ions have the same charge and size, the pseudo noble gas ion with 18 electrons in the outermost shell will be more polarising than the noble gas ion with 8 electrons.