Synthesis of prebiotic organics from CO by catalysis with meteoritic and volcanic particles.

The emergence of prebiotic organics was a mandatory step toward the origin of life. The significance of the exogenous delivery versus the in-situ synthesis from atmospheric gases is still under debate. We experimentally demonstrate that iron-rich meteoritic and volcanic particles activate and catalyse the fixation of CO, yielding the key precursors of life-building blocks.

Single-crystal Pb-NMR of wulfenite, PbMoO, aided by simultaneous measurement of phosgenite, PbClCO.

The effort for determining NMR interaction tensors from orientation-dependent spectra of single crystals may be greatly reduced by exploiting symmetry relations between atoms of the observed nuclide in the unit cell, as is well documented in the literature. In this work, we determined both the full chemical shift (CS) tensor of Pb and the unknown orientation of the rotation axis for the natural mineral phosgenite, PbClCO, from a single rotation pattern, i.e.

NMR interaction tensors of V and Pb in vanadinite, Pb(VO)Cl, determined from DFT calculations and single-crystal NMR measurements, using only one general rotation axis.

Orientation-dependent NMR spectra of a single crystal of the mineral vanadinite, Pb(VO)Cl, were acquired using only one rotation axis with a general orientation in the hexagonal crystal lattice (space group P6/m). The chemical shift (CS) tensors for the Pb on Wyckoff positions 6h and 4f, and both CS and quadrupole coupling tensor Q for V at the positions 6h were determined by including the NMR response of symmetry-related atoms in the unit cell (and in case of Pb at 4f, also the isotropic shift from MAS NMR spectra). This previously suggested 'single rotation method' greatly reduces the necessary amount of data acquisition and analysis.

Mechanical properties of modern calcite- (Mergerlia truncata) and phosphate-shelled brachiopods (Discradisca stella and Lingula anatina) determined by nanoindentation.

We measured distribution patterns of hardness and elastic modulus by nanoindentation on shells of the rhynchonelliform brachiopod Mergerlia truncata and the linguliform brachiopods Discradisca stella and Lingula anatina. The rhynchonelliformea produce calcitic shells while the linguliformea produce chitinophosphatic shells. Dorsal and ventral valves, commissure and hinge of the calcitic shell of M.

Manganoan rockbridgeite Fe4.32Mn0.62Zn0.06(PO4)3(OH)5: structure analysis and 57Fe Mössbauer spectroscopy.

The structure of the basic iron phosphate rockbridgeite [iron manganese zinc tris(phosphate) pentahydroxide] was reinvestigated with special emphasis on the cation distribution deduced from new X-ray and 57Fe Mössbauer data. Rockbridgeite is orthorhombic, space group Cmcm, and shows three different Fe sites, one with 2/m symmetry, another with m symmetry and the third in a general position. One phosphate group has the P atom on a site with m symmetry, while the other has the P atom at a site with mm symmetry.