The resurgence of the Molten-Salt Nuclear Reactors (MSR) creates interesting problems in molten-salt chemistry. As MSRs operate, the composition and physical
properties of salts change because of fission and corrosion. Since Cr is the principal corrosion product and NaCl is a common constituent, we studied the atomic
structure of molten NaCl-CrCl3. We found networks of CrCl3−
6
octahedra and an
intermediate-range order with nonmonotonic temperature behavior in a remarkable
agreement between measurements and ab initio simulations. Even though the corrosion results in minute quantities of dissolved Cr, the speciation of Cr could lead
to changes in molten-salt properties in nuclear and solar salts. In particular, we
found a much lower than expected melting temperature and a broad metastable
liquid-solid coexistence phase. The availability of Cr isotopes with very different
neutron-scattering properties makes Cr an ideal model multi-valent ion for experimental validation of new atomistic models such as neural network interatomic
potentials.
Complex structure of molten NaCl-CrCl3 salt: octahedra network and intermediate-range order
