Morphology and
Surface Structure of Silver Carboxylates
E. Aret, V. Volotchaev, S. Verhaegen, H. Meekes, E. Vlieg, G. Deroover
and C. van Roost
Cryst. Growth & Design 6 (2006) 1027-1032
Abstract:
The crystal morphology of silver laurate, silver stearate, and silver
behenate is studied. The crystal structures form a homologous series
for AgOOCnH2n-1 (for n = even). These crystals are morphologically only
isomorphous when grown at low supersaturation. The morphological
importance of the top facets depends on the supersaturation as well as
on the carbon chain length. The surface topology is studied on a
molecular scale with the use of atomic force microscopy. For all
facets, a two-dimensional birth-and-spread mechanism is found. The
measured surface structure combined with molecular visualization tools
leads to a detailed understanding of the growth and shape of these
silver carboxylates. The silver-oxygen bonds mainly determine the
morphology of the short chain compounds, while the stacking of the
carbon chains becomes more important for the long chain compounds. The
position of the silver ions on the surface is relevant for
understanding the reactivity in photothermographic applications.