Investigation of the thermal and conductive properties of oxalic acid salts with planar and undulating proton-conducting layers

• Published in: CrystEngComm Vol. 22; no. 11; pp. 231 - 241
• Main Authors: Widelicka, Ma gorzata, awniczak, Pawe, Pietraszko, Adam, Pogorzelec-Glaser, Katarzyna, api ski, Andrzej
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 21.03.2020
• Subjects: Conduction; Conductivity; Conductors; Crystallography; Oxalic acid; Physical properties; Planar structures; Protons; Quantum theory; Thermal stability
• ISSN: 1466-8033; 1466-8033
• DOI: 10.1039/c9ce01397k

The physical properties of two proton conductors 1 H -1,2,4-triazol-4-ium hydrogen oxalate (TriOX) and 1 H -imidazol-3-ium hydrogen oxalate (ImiOX) were investigated. For the ImiOX salt, we observed undulating conducting layers with cations protruding by about 20° above and below the anion plane, in contrast to the TriOX salt, in which the layers were planar. The effect of undulating conducting layers on the thermal and conductive properties of oxalic acid salts is discussed. The ImiOX salt, which contains undulating layers, exhibits a higher conductivity value ( σ dc = 1.2 × 10 −4 S m −1 at 493 K) than the TriOX salt with a planar structure ( σ dc = 1.2 × 10 −6 S m −1 at 449 K). Theoretical analysis of the Hirshfeld surface and the quantum theory of atoms in molecules (QTAiM) show that there are stronger interactions in ImiOX. The imidazolium salt has better thermal stability compared to TriOX. The physical properties of two proton conductors 1 H -1,2,4-triazol-4-ium hydrogen oxalate (TriOX) and 1 H -imidazol-3-ium hydrogen oxalate (ImiOX) were investigated.