Binding of ethanol on calcite: the role of the OH bond and its relevance to biomineralization.

The interaction of OH-containing compounds with calcite, CaCO(3), such as is required for the processes that control biomineralization, has been investigated in a low-water solution. We used ethanol (EtOH) as a simple, model, OH-containing organic compound, and observed the strength of its adsorption on calcite relative to OH from water and the consequences of the differences in interaction on crystal growth and dissolution. A combination of atomic force microscopy (AFM) and molecular dynamics (MD) simulations showed that EtOH attachment on calcite is stronger than HOH binding and that the first adsorbed layer of ethanol is highly ordered.

High-pressure anisotropic distortion of Pb3Bi2S6: a pressure-induced, reversible phase transition with migration of chemical bonds.

The compound Pb 3Bi 2S 6 is investigated by X-ray diffraction on single crystals in a diamond-anvil cell between 0.0001 and 10.5 GPa.

Comment on "Decagonal and quasi-crystalline tilings in medieval Islamic architecture".

Lu and Steinhardt (Reports, 23 February 2007, p. 1106) claimed the discovery of a large, potentially quasi-crystalline Islamic tiling in the Darb-i Imam shrine but regard the earlier Maragha tiling, previously described as quasiperiodic, as a small isolated motif. We demonstrate that the Darb-i Imam pattern is periodic and that the quasi-crystalline discs superimposed on its lattice are derivatives of the Maragha pattern.

Structure of a synthetic halogen sulfosalt, Cu3Bi2S3I3.

Cu(3)Bi(2)S(3)I(3) was crystallized during an attempt to synthesize Cu-Pb-Bi sulfosalts with iodine as the transport medium. The crystal structure was solved from a black needle-like crystal on a four-circle diffractometer with a CCD detector. The solution was obtained by direct methods and subsequent difference-Fourier syntheses.