The unique structure of [(C₄H₉)₄N]₃[Pb(NO₃)₅]—one step forward in understanding transport properties in tetra-n-butylammonium-based solid electrolytes

The crystal and molecular structure of tris(tetrabutylammonium) pentanitratoplumbate(II) was determined and characterized by single-crystal and powder X-ray diffraction and IR spectroscopy. The structure is compared to other tetra-n-butylammonium-based metal complexes with inorganic ligands, showing a significant difference in space group and local surroundings. The Pb²⁺ cation is surrounded by five NO₃⁻ groups, forming a stable complex only in the crystal field. Part of (C₄H₉)₄N⁺ cations are distorted significantly changing geometry from tetrahedra to almost flat (square) at room temperature. Discussion on possible reorientational motion of organic groups at high temperatures and its influence on ion transport processes within the crystal structure of tetra-n-butylammonium-based organic ionic plastic crystals is provided.