Characteristic of a salt-like (ionic) hydride, it has a high melting point, and it is not soluble but reactive with all protic organic solvents.

[3]: 42  Its compressive creep (per 100 hours) rapidly increases from < 1% at 350 °C to > 100% at 475 °C, meaning that LiH cannot provide mechanical support when heated.

[3]: 155 Bulk cold-pressed LiH parts can be easily machined using standard techniques and tools to micrometer precision.

In moist air the powder ignites spontaneously, forming a mixture of products including some nitrogenous compounds.

The lump material reacts with humid air, forming a superficial coating, which is a viscous fluid.

The surface condition of LiH, presence of oxides on the metal dish, etc., have a considerable effect on the ignition temperature.

Dry oxygen does not react with crystalline LiH unless heated strongly, when an almost explosive combustion occurs.

[3]: 22 LiH pellets slowly expand in moist air, forming LiOH; however, the expansion rate is below 10% within 24 hours in a pressure of 2 Torr of water vapor.

[11] Lithium hydride (LiH) is sometimes a desirable material for the shielding of nuclear reactors, with the isotope lithium-6 (Li-6), and it can be fabricated by casting.

[citation needed] In hydrogen warheads of the Teller–Ulam design, a nuclear fission trigger explodes to heat and compress the lithium-6 deuteride, and to bombard the 6LiD with neutrons to produce tritium in an exothermic reaction: The deuterium and tritium then fuse to produce helium, one neutron, and 17.59 MeV of free energy in the form of gamma rays, kinetic energy, etc.

[citation needed] Before the Castle Bravo nuclear weapons test in 1954, it was thought that only the less common isotope 6Li would breed tritium when struck with fast neutrons.

The Castle Bravo test showed (accidentally) that the more plentiful 7Li also does so under extreme conditions, albeit by an endothermic reaction.

At concentrations of 5–55 mg/m3 in air the dust is extremely irritating to the mucous membranes and skin and may cause an allergic reaction.

LiH is normally transported in oil, using containers made of ceramic, certain plastics or steel, and is handled in an atmosphere of dry argon or helium.