Lithium and Lead(II) Butyrates Binary System. Pure Compounds and an Intermediate Salt: From 2D to 3D Coordination Polymers

• Published in: Crystal growth & design 2011-03, Vol.11 (3), p.759-767
• Main Authors: Casado, F. J. Martínez, Riesco, M. Ramos, Silva, I. da, Yélamos, M. I. Redondo, Labrador, A, Cheda, J. A. Rodríguez
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Materials science; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Phase diagrams of metals and alloys; Physics; Porous materials; granular materials; Solid-solid transitions; Specific materials; Specific phase transitions; Structure of solids and liquids; crystallography; Structure of specific crystalline solids
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/cg101272n

The binary phase diagram between lithium and lead(II) butyrates, [xLiC3H7CO2 + (1 − x)Pb(C3H7CO2)2] was determined by differential scanning calorimetry, in order to investigate the formation of intermediate salts. A complex or intermediate salt (with a 1:1 stoichiometry) was found during the solution of the phase diagram. Crystals of this salt, which melt incongruently at T fus = 443.2 K, were obtained later by crystallization. The structures of the crystal phase of both pure compounds and the intermediate salt were solved by single crystal and powder X-ray diffraction, using synchrotron radiation. Lithium and lead(II) butyrates present a monoclinic unit cell (P21/c and P21/m, respectively). Both pure salts show a bilayered arrangement, in a structure of 2D coordination polymers, as usually metal alkanoates do. Nevertheless, the complex forms a microporous 3D ionic network (tetragonal, I41/a), very atypical in this kind of organic salts. Binary phase diagrams are proved to be a powerful tool to detect and predict the formation of intermediate crystals.