Redetermination and new description of the crystal structure of vanthoffite, NaMg(SO).

The crystal structure of vanthoffite {hexa-sodium magnesium tetra-kis[sulfate-(VI)]}, NaMg(SO), was solved in the year 1964 on a synthetic sample [Fischer & Hellner (1964 ▸). , 1613]. Here we report a redetermination of its crystal structure on a mineral sample with improved precision.

Ikaite nucleation at 35 °C challenges the use of glendonite as a paleotemperature indicator.

Glendonites have been found worldwide in marine sediments from the Neoproterozoic Era to the Quaternary Period. The precursor of glendonite, ikaite (CaCO · 6HO), is metastable and has only been observed in nature at temperatures <7 °C. Therefore, glendonites in the sedimentary record are commonly used as paleotemperature indicators.

A Novel Synthesis Routine for Woodwardite and Its Affinity towards Light (La, Ce, Nd) and Heavy (Gd and Y) Rare Earth Elements.

A synthetic Cu-Al-SO₄ layered double hydroxide (LDH), analogue to the mineral woodwardite [CuAl(SO₄)(OH)₂·nH₂O], with x < 0.5 and n ≤ 3x/2, was synthesised by adding a solution of Cu and Al sulphates to a solution with NaOH. The pH values were kept constant at 8.

Metal transport and remobilisation in a basin affected by acid mine drainage: the role of ochreous amorphous precipitates.

Metal-polluted mine waters represent a major threat to the quality of waters and sediments in a downstream basin. At the confluence between acidic mine waters and the unpolluted waters of the Gromolo Torrent (Liguria, North-West Italy), the massive formation of an ochreous amorphous precipitate takes place. This precipitate forms a soft blanket that covers the torrent bed and can be observed down to its mouth in the sea.

Isotope ratios of H, C, and O in CO2 and H2O of the martian atmosphere.

Stable isotope ratios of H, C, and O are powerful indicators of a wide variety of planetary geophysical processes, and for Mars they reveal the record of loss of its atmosphere and subsequent interactions with its surface such as carbonate formation. We report in situ measurements of the isotopic ratios of D/H and (18)O/(16)O in water and (13)C/(12)C, (18)O/(16)O, (17)O/(16)O, and (13)C(18)O/(12)C(16)O in carbon dioxide, made in the martian atmosphere at Gale Crater from the Curiosity rover using the Sample Analysis at Mars (SAM)'s tunable laser spectrometer (TLS). Comparison between our measurements in the modern atmosphere and those of martian meteorites such as ALH 84001 implies that the martian reservoirs of CO2 and H2O were largely established ~4 billion years ago, but that atmospheric loss or surface interaction may be still ongoing.

Comparison between beryllium and diamond-backing plates in diamond-anvil cells: application to single-crystal x-ray diffraction high-pressure data.

A direct comparison between two complete intensity datasets, collected on the same sample loaded in two identical diamond-anvil pressure cells equipped, respectively, with beryllium and diamond-backing plates was performed. The results clearly demonstrate that the use of diamond-backing plates significantly improves the quality of crystal structure data. There is a decrease in the internal R factor for averaging, structure refinement agreement factors, and in the errors and uncertainties of the atomic coordinates, atomic displacement parameters, and individual bond lengths.

Time-response relationship of nano and micro particle induced lung inflammation. Quartz as reference compound.

An increasing number of engineered particles, including nanoparticles, are being manufactured, increasing the need for simple low-dose toxicological screening methods. This study aimed to investigate the kinetics of biomarkers related to acute and sub-chronic particle-induced lung inflammation of quartz. Mice were intratracheal instilled with 50 µg of microsized or nanosized quartz.

Identification of monoclinic calcium pyrophosphate dihydrate and hydroxyapatite in human sclera using Raman microspectroscopy.

Raman microspectroscopy was first used to determine the composition of a calcified plaque located at the pterygium-excision site of a 51-year-old female patient's left nasal sclera after surgery. It was unexpectedly found that the Raman spectrum of the calcified sample at 1149, 1108, 1049, 756, 517, 376 and 352/cm was similar to the Raman spectrum of monoclinic form of calcium pyrophosphate dihydrate (CPPD) crystal, but differed from the Raman spectrum of triclinic form of CPPD. An additional peak at 958/cm was also observed in the Raman spectrum of the calcified plaque, which was identical to the characteristic peak at 958/cm of hydroxyapatite (HA).

Modular crystals as modulated structures: the case of the lillianite homologous series.

The use of the superspace formalism is extended to the description and refinement of the homologous series of modular structures with two symmetry-related modules with different orientations. The lillianite homologous series has been taken as a study case. Starting from a commensurate modulated composite description with two basic subsystems corresponding to the two different modules, it is shown how a more efficient description can be achieved using so-called zigzag modulation functions.

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.

Arctic vegetation damage by winter-generated coal mining pollution released upon thawing.

Acid mine drainage (known as AMD) is a well-known environmental problem resulting from the oxidation of sulfidic mine waste. In cold regions, AMD is often considered limited by low temperatures most of the year and observed environmental impact is related to pollution generated during the warm summer period. Here we show that heat generation within an oxidizing, sulfidic, coal-mining waste-rock pile in Svalbard (78 degrees N) is high enough to keep the pile warm (roughly 5 degrees C throughout the year) despite mean annual air temperatures below -5 degrees C.

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.