The effects of pressure on the crystal structure of the three known polymorphs of magnesium sulfate (α-MgSO4, β-MgSO4, and γ-MgSO4) have been theoretically studied by means of density-functional theory calculations up to 45 GPa. We determined that under ambient conditions γ-MgSO4 is an unstable polymorph, which decomposes into MgO + SO3, and that the response of the other two polymorphs to hydr...

Biominerals and biomaterials with unique microstructure are mainly consisted of organic and inorganic materials, and exhibit excellent biological and mechanical properties. The formation mechanism of biomineral indicated that the organic matrixes have an important influence on the morphology and structure of the inorganic matrix material in the process of biomineralization. However, the biomine...

The incorporation of sodium and aluminium in magnesium silicate hydrate phases (M-S-H), possible binding cement, was investigated. Magnesium alumino containing (M-A-S-H N samples) were synthesized batch experiments with NaNO3 ~ 100 mmol/L at Mg/Si ratios equal to 0.8 1.2, Al/Si 0, 0.1 0.2, equilibrated 20 50 °C. Thermogravimetric analysis (TGA), X-rays diffraction (XRD), 29Si MAS NMR data showe...

Lithium has limited biological activity and can readily replace aluminium, magnesium iron ions in aluminosilicates, making it a proxy for the inorganic silicate cycle its potential link to carbon cycle. Data from North Pacific Ocean, tropical Indian Southern Ocean Red Sea suggest that salinity normalised dissolved lithium concentrations vary by up 2-3% Indo-Pacific Ocean. The highest were measu...

Gibbsite and bayerite may be distinguished by Raman spectroscopy (Huneke et al., 1980), with the laser Raman microprobe providing a non-destructive method of analysing small quantities particularly where the habit and/or fine grain size defy other techniques (e.g. Crestin-Desjobert et al., 1987). The Raman spectra of other polymorphs of aluminium hydroxide have not been recorded. This study det...

Two conformational polymorphs of novel 2-[2-(3-cyano-4,6-dimethyl-2-oxo-2H-pyridin-1-yl)-ethoxy]-4,6-dimethyl nicotinonitrile have been developed. The crystal structure of both polymorphs (1a and 1b) seems to be stabilized by weak interactions. A difference was observed in the packing of both polymorphs. Polymorph 1b has a better binding affinity with the cyclooxygenase (COX-2) receptor than th...

Using different techniques, we studied the possible formation of ondansetron polymorphs. Ondansetron is a carbazol antiemetic that acts as a competitive, selective inhibitor of 5-HT3 serotonin receptors. The polymorphs were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results suggest that the compounds are not true crystallographic polymorphs, but instead ar...

Most of calcium silicate hydrate or calcium aluminosilicate hydrate, CS(A)H, and related phases are relevant to Cement industry and have potential as geothermal well sealants as well as autoclaved construction materials. The CS(A)H system is highly complex and is comprised of crystalline to amorphous phases with variable composition that build up a wide family of phases, which are interesting f...