EXAFS determination of the structure of silver stearate, [Ag(O2C(CH2)16CH3]2, and the effect of temperature on the silver coordination sphere

The structure of silver stearate, [Ag(O2C(CH2)16CH3]2, has been refined using Ag K-EXAFS spectroscopy and known unit cell parameters. The silver carboxylate complex is similar to known short chain silver carboxylate derivatives and is a dimer formed from an eight-membered ring comprised of two silver atoms bridged by two carboxylates from the stearate molecules. The Ag ··· Ag distance is 2.90 (0.03) Å, similar to the bond distance in metallic silver. The dimers are further bonded to each other by long 2.60 Å, AgO bonds. Moderate increases in temperature does not affect the structure, however, upon exposure to higher temperatures a new structure results which exhibits a Ag ··· Ag distance of 4.2 Å.