Uranium carbides are receiving renewed interest as a preferred nuclear fuel composition for advanced reactors due to their numerous favorable properties. Like many other refractory and transition metal carbides these compounds exist in both hypo- and hyper-stoichiometric compositions which results in significant variations in physical, thermal, and mechanical properties^[1]. This article will show its crystal structure.

Figure 2. Crystal structure of uranium carbide^[2].

Uranium-carbon system in solid state has three compounds: UC, UC2, and U2C3. In the case of uranium carbides, uranium monocarbide UC is stable in a large domain of compositions in its rock-salt structure (Fig. 1) because of its solubility with the tetragonal UC2 phase^[2].

References

[1] Uranium carbide properties for advanced fuel modeling – A review. doi:10.1016/j.jnucmat.2021.153145.

[2] Inorganic Synthesis of Actinides, in Modern Inorganic Synthetic Chemistry (Second Edition), 2017.