Question

Is lithium hydride, ionic or covalent bonding?

Answer 1

Hint: $LiH$ or lithium hydride is ionic in nature. Lithium loses an electron and hydrogen accepts that electron. This results in the formation of an ionic bond. It is a very good conductor of heat. It is not soluble. The electronegativity difference is also reasonably high between the two atoms.

Complete answer:
The formula of lithium hydride is $LiH$ . It is an inorganic, colorless solid compound. Its melting point is high and it is not soluble but is reactive with all protic organic solvents. It is diamagnetic. $LiH$ is produced by treating lithium metal with hydrogen gas:
 $2Li+H_2\to 2LiH$
Lithium and hydrogen are bonded together by ionic bond as Lithium loses an electron and becomes $L{i}^{+}$ and hydrogen accepts that electron and becomes $H^{-}$ . To form an ionic bond there must be more electronegative difference between two atoms and here electronegativity of $Li=0.98$ and of $H=2.2$ , the electronegativity is big so it is ionic. The valence electrons in hydrogen are closer to the nucleus because of this also the electronegativity pull is greater and due to more difference between the electronegativities they cannot form covalent bonds. Also when they react with each other, each of them share their single valence electrons to make a bond between the two atoms. It is reasonably polar.

Note:
The bonding in lithium hydride is believed to be largely ionic; i.e. Li +H – because of the fact that hydrogen is released from the anode on electrolysis of the molten salt. $LiH$ reacts violently with water. It is insoluble in alcohol and acetone. It is a good conductor of heat and its conductivity decreases when the temperature increases. It is stable under normal conditions. $LiH$ is a strong reducing agent which decomposes violently in contact with most oxidizing materials. It burns readily in the air.