What Is Lithium Hydride?
Lithium hydride (LiH) is a compound notable for its white color in pure form, though commercial products often appear gray due to light exposure. It reacts violently with water, producing hydrogen, and poses explosion risks in humid air or with static electricity. It is corrosive and requires careful handling.
Uses of Lithium Hydride
Valued for its high hydrogen content, lithium hydride is explored for efficient hydrogen storage and transportation. It’s also considered a promising material for radiation shielding in nuclear reactors due to its beneficial properties compared to conventional materials like concrete, water, and lead.
Properties of Lithium Hydride
With a melting point of 680°C and slight solubility in diethyl ether, lithium hydride is stable and does not decompose in dry air at room temperature but reacts with alcohols and decomposes when exposed to light. It forms a colorless cubic ionic crystal with a sodium chloride-type structure.
Structure of Lithium Hydride
Lithium hydride has a chemical formula of LiH, a formula weight of 7.95, and a density of 0.82 g/cm3. It consists of H– and Li+ ions with a Li-H distance of 2.04 Å.
Other Information on Lithium Hydride
Synthesis of Lithium Hydride
Produced by reacting molten lithium with hydrogen gas above 600°C, lithium hydride’s yield can be optimized by adding carbon and increasing pressure. It can also result from the thermal decomposition of various lithium compounds.
Reactivity of Lithium Hydride
It reacts explosively with moisture and is highly reactive with water and protic reagents, forming lithium hydroxide, oxide, and carbonate in humid air. Lithium hydride reacts with sulfur dioxide, acetylene, organic acids, and aluminum chloride, yielding various compounds, including lithium aluminum hydride.
Hazards of Lithium Hydride
Lithium hydride poses explosion risks in humid air and can cause mucous membrane and skin irritation. Transportation and processing require oil containers and a dry argon or helium atmosphere to mitigate hazards.