Results for “KNiCl3”

DOE OSTI2020

Materials Data on KNiCl3 by Materials Project

KNiCl3 crystallizes in the hexagonal P6_3cm space group. The structure is three-dimensional. K1+ is bonded in a 9-coordinate geometry to nine Cl1- atoms. There are a spread of K–Cl bond distances ranging from 3.30–3.48 Å. There are two inequivalent Ni2+ sites. In the first Ni2+ site, Ni2+ is bonded to six equivalent Cl1- atoms to form face-sharing NiCl6 octahedra. There are three shorter (2.39 Å) and three longer (2.42 Å) Ni–Cl bond lengths. In the second Ni2+ site, Ni2+ is bonded to six equivalent Cl1- atoms to form face-sharing NiCl6 octahedra. There are three shorter (2.40 Å) and three longer (2.41 Å) Ni–Cl bond lengths. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 5-coordinate geometry to three equivalent K1+ and two equivalent Ni2+ atoms. In the second Cl1- site, Cl1- is bonded in a 5-coordinate geometry to three equivalent K1+ and two equivalent Ni2+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Chloride Salt Purification by Reaction With Thionyl Chloride Vapors to Remove Oxygen, Oxygenated Compounds, and Hydroxides

Molten chloride salts (including MgCl 2 , KCl, NaCl, and ZnCl 2 ) are being considered for heat transfer media for renewable (solar) and nuclear power generators, as fuel carrier for nuclear reactors, and as thermal energy storage media. Impurities such as oxygen, hydroxides, moisture, and sulfur are known to negatively influence the corrosion of materials in contact with the salt (e.g., structural metals). Commercially available chloride salts come with a range of impurities. Before using the chloride salts at high temperature, it is desirable to remove the impurities to increase the performance of the salt and reduce corrosion. In this study, we tested the use of thionyl chloride vaporized into a stream of argon to react with oxygenated impurities in a mixture of MgCl 2 -KCl-NaCl, removing them as HCl and SO 2 . The reagent was bubbled through the salt when both above and below the melting point. The reaction was followed using thermocouple data from the salt and by Fourier transform infrared (FTIR) spectroscopy on the exhaust of the reactor. The reaction kinetics were followed by comparing the peaks from SO 2 product to SOCl 2 reagent in the FTIR spectra. The purity of the salt was assessed at the end of the purification process by x-ray diffraction and inductively coupled plasma analysis. Although the process was effective in removing the oxygen content of the mixture, ternary compounds were formed in the process, including KNiCl 3 and KMgCl 3 . The nickel in KNiCl 3 came from the reaction between the salt and the nickel vessel. Thus, these experiments suggest that improvements to the process must be made before using SOCl 2 vapors for the purification of chloride salts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗