Ravnsbaek, Dorthe B. Ley, Morten B. Lee, Young-Su Hagemann, Hans D'Anna, Vincenza Cho, Young Whan Filinchuk, Yaroslav Jensen, Torben R. 2024-01-20T15:01:25Z 2024-01-20T15:01:25Z 2021-09-05 2012-05 0360-3199 https://pubs.kist.re.kr/handle/201004/129302 A new sodium-yttrium borohydride-chloride, NaY(BH4)(2)Cl-2, is obtained by a combination of mechanochemical synthesis and annealing of NaBH4-YCl3 mixtures and is characterized by in-situ synchrotron radiation X-ray powder diffraction, density functional theory, thermal analysis and vibrational spectroscopy. Several simultaneous and coupled reactions occur during the synthesis, also yielding Na3YCl6 and Na(BH4)(1-x)Cl-x besides the title compound. The polymeric pseudo-orthorhombic crystal structure of NaY(BH4)(2)Cl-2 (space group P2/c) is built of edge- and corner-sharing octahedral coordination polyhedra of yttrium (4Cl + 2BH(4)) and sodium (2Cl + 4BH(4)). The structure is isomorphous to the high temperature polymorph of NaYCl4. The BH4 units in NaY(BH4)(2)Cl-2 are located only on the larger of the two independent anion sites in NaYCl4. Density functional theory optimization of the experimental structure suggests that the BH4 units act as eta(3)-ligands (face-sharing) towards yttrium and eta(1)-ligands (corner-sharing) towards sodium. Raman spectroscopy confirms this BH4 configuration. NaY(BH4)(2)Cl-2 decomposes at similar to 300 degrees C under formation of Na3YCl6, while the latter compound at higher temperatures reacts with Na(BH4)(1-x)Cl-x to form NaCl and possibly amorphous products. The reactions are associated with mass losses of 2.62 and 3.78 wt% for the NaBH4-YCl3 (3:1) and (4:1) samples, respectively. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. English PERGAMON-ELSEVIER SCIENCE LTD CRYSTALLOGRAPHY BEAMLINE CRYSTAL-STRUCTURES TERNARY CHLORIDES POLYMORPHISM Y(BH4)(3) STORAGE LIBH4 DECOMPOSITION BEHAVIOR HYDRIDES A mixed-cation mixed-anion borohydride NaY(BH4)(2)Cl-2 Article 10.1016/j.ijhydene.2012.02.130 1 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, v.37, no.10, pp.8428 - 8438 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 37 10 8428 8438 scie scopus 000305040400036 2-s2.0-84860364608 Chemistry, Physical Electrochemistry Energy & Fuels Chemistry Electrochemistry Energy & Fuels Article CRYSTALLOGRAPHY BEAMLINE CRYSTAL-STRUCTURES TERNARY CHLORIDES POLYMORPHISM Y(BH4)(3) STORAGE LIBH4 DECOMPOSITION BEHAVIOR HYDRIDES Hydrides X-ray diffraction Solid state structure Solid phase synthesis Transition metal