Facile Oxide to Chalcogenide Conversion for Actinides Using the Boron-Chalcogen Mixture Method.

Area of Science:

• Materials Science
• Inorganic Chemistry
• Actinide Chemistry

Background:

• Actinide chalcogenides are crucial for studying 5f electron behavior in soft ligand environments.
• Synthesizing phase-pure actinide chalcogenides is challenging due to actinides' high oxygen affinity, often resulting in oxide impurities.
• Existing methods require oxygen-free precursors, limiting material accessibility.

Purpose of the Study:

• To introduce a novel synthetic method for producing phase-pure actinide chalcogenides.
• To address the challenge of oxide impurities in actinide chalcogenide synthesis.
• To demonstrate the versatility of the new method across various actinide chalcogenide classes.

Main Methods:

• Development of the boron-chalcogen mixture (BCM) method.
• Utilizing boron as an "oxygen sponge" to remove oxygen from oxide precursors.
• Employing elemental chalcogens to convert oxide precursors into oxygen-free chalcogenide reagents.

Main Results:

• Successful synthesis of phase-pure uranium chalcogenides using the BCM method.
• Demonstration of the method's broad functionality through various syntheses.
• Preparation of new rare earth uranium sulfides and alkali-thorium thiophosphates, validating the approach.
• Successful oxide to sulfide transformation and in situ generation of actinide chalcogenides in flux crystal growth.

Conclusions:

• The BCM method provides a robust solution for synthesizing pure actinide chalcogenides.
• This technique overcomes the persistent challenge of oxygen contamination in actinide materials.
• The method facilitates the creation of novel actinide chalcogenide compounds and expands synthetic possibilities.