Crystal structure determination of the silver carboxylate dimer [Ag(O2C22H43)]2, silver behenate, using powder X-ray diffraction methods

High-resolution powder X-ray diffraction has been used to determine the crystal structure of silver behenate, [Ag(O2C(CH2)(20)CH3](2). Using CASTEP density functional plane wave pseudo-potential techniques to obtain an optimized structural model, Rietveld refinement of the structure gives R-wp = 8.66%. The unit cell is triclinic, space group P (1) over bar, with cell dimensions of a = 4.1769(2) angstrom, b=4.7218(2) angstrom, c=58.3385(1) angstrom, alpha = 89.440(3)degrees, beta = 89.634(3)degrees, gamma = 75.854(1)degrees. The structure is characterized by an 8-membered ring dimer of Ag atoms and carboxyl groups with a fully extended all-trans configuration of the alkyl side chains. The dimers are joined by four-membered Ag-O rings creating a polymeric network, giving rise to one-dimensional chains along the b-axis. This structure is supported by EXAFS measurements of the local structure around the silver atoms and IR measurements. (C) 2011 International Centre for Diffraction Data. [DOI: 10.1154/1.3661981]