the qom formation, which hosts the mazraeh celestite deposit, contains dominantly limestones, marl and subordinate evaporites deposited in shallow marine environments. petrographic evidence indicates that the celestite deposits were formed by replacement of limestone. the presence of carbonate inclusions within celestite crystals as well as the pseudomorphic habits of some crystals suggests tha...

 The crystal structure of two B-type carbonated apatite samples was re-analyzed, using the data of Wilson et al (2006). By applying the least squares method for the determination of carbon and oxygen atoms, a slightly different result was obtained, suggesting that the carbonate ion is not rigorously planar. Keywords Carbonated apatite, Carbonate, Xray diffraction.

The Raman wavenumber of the symmetric stretching vibration of carbonate ion (ν1-CO32-) was measured in three aqueous solutions containing 2.0 mol·L-1 Na2CO3 and 0.20, 0.42, or 0.92 mol·L-1 NaCl, respectively, from 122 to 1538 MPa at 22 °C using a moissanite anvil cell. The ν1 Raman signal linearly shifted to higher wavenumbers with increasing pressure. Most importantly, the slope of ν1-CO32- Ra...

The molecular diffusion coefficients of dissolved carbon dioxide ðCO2Þ, bicarbonate ion ðHCO 3 Þ, and carbonate ion ðCO 3 Þ are fundamental physico-chemical constants and are of practical significance in various disciplines including geochemistry, biology, and medicine. Yet, very little experimental data is available, for instance, on the bicarbonate and carbonate ion diffusion coefficient. Fur...

Guanidinium carbonate was used in this study as a simple proxy for the biologically relevant arginine-carbonate interactions in water. Molecular dynamics (MD) simulations of guanidinium carbonate were performed with nonpolarizible water using two implementations of the ion force fields. In the first, the ions had full charges, while in the second, the ions had reduced charges in order to effect...

A range of crystalline and nano-sized carbonate- and silicate-substituted hydroxyapatite has been successfully produced by using continuous hydrothermal flow synthesis technology. Ion-substituted calcium phosphates are better candidates for bone replacement applications (due to improved bioactivity) as compared to phase-pure hydroxyapatite. Urea was used as a carbonate source for synthesising p...

Southern Ocean acidification via anthropogenic CO(2) uptake is expected to be detrimental to multiple calcifying plankton species by lowering the concentration of carbonate ion (CO(3)(2-)) to levels where calcium carbonate (both aragonite and calcite) shells begin to dissolve. Natural seasonal variations in carbonate ion concentrations could either hasten or dampen the future onset of this unde...

The evolutionary success of planktic calcifiers during the Phanerozoic stabilized the climate system by introducing a new mechanism that acts to buffer ocean carbonate-ion concentration: the saturation-dependent preservation of carbonate in sea-floor sediments. Before this, buffering was primarily accomplished by adjustment of shallow-water carbonate deposition to balance oceanic inputs from we...