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Estimation of Thermodynamic Properties of Metal Hydroborates
Author(s) -
Hagemann Hans
Publication year - 2019
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201901776
Subject(s) - enthalpy , gibbs free energy , alkali metal , thermodynamics , standard enthalpy of formation , chemistry , lanthanide , lattice energy , ionic bonding , metal , standard enthalpy change of formation , crystallography , ion , crystal structure , physics , organic chemistry
Abstract Metal hydroborates from M(BH 4 ) n to M x (B 12 H 12 ) y currently attract a strong interest for potential applications in the field of hydrogen storage and more recently as solid ionic conductors. While thermodynamic data for the alkali borohydrides (MBH 4 ) are well known, experimental data for other compounds are cruelly lacking. Using a combination of theoretical (DFT) and experimental data, we calculate the lattice enthalpy for a series of borohydrides. The comparison with literature data show that these lattice enthalpies are very similar to those of the corresponding metal bromides. This similarity is at the origin of a good correlation between the formation enthalpy of bromides and borohydrides which is then used to estimate the previously unknown formation enthalpy of M II (BH 4 ) 2 (M II =divalent cation) and Ln(BH 4 ) 3 (Ln=lanthanide). The Gibbs free energy of formation of M 2 (B 12 H 12 ) (M=alkali metal) is also estimated.