Synthesis, Polymorphism and Thermal Decomposition Process of (n-C4H9)4N RE(BH4)4 for RE = Ho, Tm and Yb

Wojciech Wegner; Tomasz Jaroń

doi:10.3390/ma14061329

Synthesis, Polymorphism and Thermal Decomposition Process of (n-C₄H₉)₄N RE(BH₄)₄ for RE = Ho, Tm and Yb

Materials (Basel). 2021 Mar 10;14(6):1329. doi: 10.3390/ma14061329.

Authors

Wojciech Wegner^{1

2}, Tomasz Jaroń²

Affiliations

¹ College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland.
² Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland.

Abstract

In total, three novel organic derivatives of lanthanide borohydrides, n-But₄NRE(BH₄)₄ (TBAREB), RE = Ho, Tm, Yb, have been prepared utilizing mechanochemical synthesis and purified via solvent extraction. Studies by single crystal and powder X-ray diffraction (SC-XRD and PXRD) revealed that they crystalize in two polymorphic forms, α- and β-TBAREB, adopting monoclinic (P2₁/c) and orthorhombic (Pnna) unit cells, previously found in TBAYB and TBAScB, respectively. Thermal decomposition of these compounds has been investigated using thermogravimetric analysis and differential scanning calorimetry (TGA/DSC) measurements, along with the analysis of the gaseous products with mass spectrometry (MS) and with analysis of the solid decomposition products with PXRD. TBAHoB and TBAYbB melt around 75 °C, which renders them new ionic liquids with relatively low melting points among borohydrides.

Keywords: borohydrides; crystal structures; hydrogen storage; lanthanides; polymorphism; rare-earth elements; thermal stability.

Abstract

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