Physical Properties of Lithium Hydride

Lithium hydride is the inorganic compound with the formula LiH. It is a colorless solid, although commercial samples are gray. Characteristic of a salt-like, or ionic, hydride, it has a high melting point and is not soluble in any solvent with which it does not react. With a molecular mass of slightly less than 8, it is the lightest ionic compound.

LiH is a diamagnetic and an ionic conductor with a conductivity gradually increasing from 2×10−5 Ohm−1cm−1 at 443 °C to 0.18 Ohm−1cm−1 at 754 °C; there is no discontinuity in this increase through the melting point. The dielectric constant of LiH decreases from 13.0 (static, low frequencies) to 3.6 (visible light frequencies). LiH is a soft material with the Mohs hardness of 3.5. Its compressive creep (per 100 hours) rapidly increases from <1% at 350 °C to >100% at 475 °C meaning that LiH can't provide mechanical support when heated.

The thermal conductivity of LiH decreases with temperature and depends on morphology: the corresponding values are 0.125 W/(cm K) for crystals and 0.0695 W/(cm K) for compacts at 50 °C, and 0.036 W/(cm K) for crystals and 0.0432 W/(cm K) for compacts at 500 °C. The linear thermal expansion coefficient is 4.2×10−5/°C at room temperature.

Read More: Lithium Hydride for sale