Electron Precise Sodium Carbaboride Nanocrystals from Molten Salts: Single Sources to Boron Carbides
- 22 January 2021
- journal article
- research article
- Published by American Chemical Society (ACS) in Inorganic Chemistry
- Vol. 60 (7), 4252-4260
- https://doi.org/10.1021/acs.inorgchem.0c03501
Abstract
Boron-rich solids exhibit specific crystal structures and unique properties, which are only very scarcely addressed in nanoparticles. In this work, we address the original inorganic structural chemistry and reactivity of boron-rich nanoparticles, by reporting the first occurrence of sodium carbaboride nanocrystals based on the NaB5C crystal structure. To design these sub-10 nm nano-objects, we use liquid-phase synthesis in molten salts at 900 °C. By combining a set of characterization tools including powder X-ray powder diffraction, transmission electron microscopy, solid-state nuclear magnetic resonance coupled to DFT modeling, and X-ray photoelectron spectroscopy, we demonstrate that these nanocrystals deviate from the ideal stoichiometry reported for the bulk compound. We suggest that the carbon and sodium contents compensate each other to ensure that the octahedral cluster-based framework is stabilized by fulfilling an electron counting rule. These nanocrystals encompass substituted octahedral covalent structural building units not reported in the related bulk compound. They then shed new light on the ability of nanoparticles to host wide solid solution ranges in covalent solids and then to yield new solids. We finally show that these nanocrystals are efficient single sources of boron and carbon to form a nanostructured boron carbide, thus paving the way to new nanostructured materials.Funding Information
- China Scholarship Council
- Minist?re fran?ais de l'Enseignement sup?rieur, de la Recherche et de l'Innovation
- GENCI-IDRIS
This publication has 50 references indexed in Scilit:
- Emergent mystery in the Kondo insulator samarium hexaborideNature Reviews Physics, 2020
- Rediscovering the Crystal Chemistry of BoridesAdvanced Materials, 2017
- Low Temperature Synthesis and Surface Plasmon Resonance of Colloidal Lanthanum Hexaboride (LaB6) NanocrystalsChemistry of Materials, 2015
- Boron: Elementary Challenge for Experimenters and TheoreticiansAngewandte Chemie, 2009
- A Unifying Electron-Counting Rule for Macropolyhedral Boranes, Metallaboranes, and MetallocenesJournal of the American Chemical Society, 2001
- Crystal and electronic structure of BaB6 in comparison with CaB6 and molecular [B6H6]2−Solid State Sciences, 2001
- A General Theory for Cluster and Ring Compounds of the Main Group and Transition ElementsNature Physical Science, 1972
- The structural significance of the number of skeletal bonding electron-pairs in carboranes, the higher boranes and borane anions, and various transition-metal carbonyl cluster compoundsJournal of the Chemical Society D: Chemical Communications, 1971
- The electronic structure of the borides M B 6Proceedings of the Royal Society of London. Series A - Mathematical and Physical Sciences, 1954
- Intermetallische VerbindungenAngewandte Chemie, 1939