Structural and Thermodynamic Study on Short Metal Alkanoates: Lithium Propanoate and Pentanoate

• Published in: The journal of physical chemistry. B Vol. 113; no. 39; pp. 12896 - 12902
• Main Authors: Martínez Casado, F. J, Riesco, M. Ramos, García Pérez, M. V, Redondo, M. I, López-Andrés, S, Rodríguez Cheda, J. A
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 01-10-2009
• Subjects: B: Macromolecules, Soft Matter; Crystallography, X-Ray; Lithium - chemistry; Molecular Conformation; Pentanoic Acids - chemistry; Propionates - chemistry; Spectroscopy, Fourier Transform Infrared; Thermodynamics; Valerates - chemistry
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp9047715

Lithium propanoate and pentanoate were characterized by DSC, single crystal and powder XRD and FTIR and impedance spectroscopies. Lithium propanoate presents a solid-to-solid transition (SII−SI) at T ss = (549.1 ± 0.7) K on first heating that varies on the second and next ones, followed by a fusion at T f = (606.1 ± 0.5) K. For lithium pentanoate, two solid-to-solid transitions (SIII−SII and SII−SI), at T ss = (205.5 ± 0.5) K and T ss = (325.2 ± 0.7) K, respectively, and a melting point at T f = (576.5 ± 0.3) K were found. The crystal structures for both compounds were characterized at 100 and 298 K (and for the lithium propanoate also at 160 K). Single-crystal XRD showed that the SII phase of both compounds has a monoclinic structure with the same symmetry group (P21/c). This is the first time that a single-crystal structure has been reported for any member of the lithium alkanoates series, so far. FTIR and impedance spectroscopies were also carried out to better characterize the solid phases in these compounds.