According to a recent Reuters story, a number of multinational companies have exposure to supply volatility with rare earth elements.

In the June 27 Reuters story, it was reported “Companies such as Raytheon Co (RTN.N), Lockheed Martin Corp (LMT.N) and BAE Systems Plc (BAES.L) all make sophisticated missiles that use rare earths metals in their guidance systems, and sensors. Lockheed and BAE declined to comment. Apple Inc (AAPL.O) uses rare earth elements in speakers, cameras and to make phones vibrate.” 

Reuters also reports that the United States imported $160 million of rare earth compounds and metals in 2018, up nearly 17% from 2017. Around 60% of it was used in catalysts for oil refining and in vehicle engines.

The rare earth elements are truly “mission critical” and irreplaceable. There is a great deal of work underway in the USA and around the world to find replacements for rare earth elements. The massive challenge facing scientists is well illustrated in the Katherine Ann Martin’s Vanderbilt University PhD thesis relating to evaluation of rare eaerth substitutes for the production of (oil) catalysts. A portion of the report is set forth below.

As part of a long-range project to develop inexpensive, earth-abundant alternatives to the use of rare-earth metals in catalysts, it was discovered that an unusual color is generated when solutions of Ca[1,3-(SiMe3)2C3H3]2(thf)2 and terypyridine are mixed in toluene. As the Ca2+ center lacks valence electrons, the deep blue coloration almost certainly arises from a ligand-to-metal charge transfer phenomenon. It was further determined that the color arises with Li+ and K+ centers in addition to Ca2+, and with the [1-(SiMe3)C3H3]– and [N(SiMe3)2]– anions as well. The key requirements thus appear to be a Group 1 or 2 metal center, terpyridine, a noncoordinating solvent, and a ligand that contains delocalized π-electrons, such as the bulky amido or allyl ligands used here. All available information indicates that the terpyridine compounds being synthesized exist in a dynamic equilibrium in solution, and the terpyridines are weakly bound to the metal. 

Isolation of Ca(η1-C3H5)(η3-C3H5)(18-crown-6) demonstrates that it is possible to manipulate the hapticity of a ligand on a Group 2 center by adjusting the electron density on the metal with a suitably strong donor ligand. Further use of this capability could lead to the development of more active catalysts based on earth-abundant Group 2 metals.

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