Certification of the phase compositions of the three NIST Reference Clinkers will be based upon more than one independent method. The current reference values were established using an optical microscope examination, with additional optical microscope data taken from an ASTM C 1356 round robin. The present X-ray powder diffraction (XRD) study provides a second, independent estimate of the phase...

Certification of the phase compositions of the three NIST Reference Clinkers will be based upon more than one independent method. The current reference values were established using an optical microscope examination, with additional optical microscope data taken from an ASTM C 1356 round robin. The present X-ray powder diffraction (XRD) study provides the second, independent estimate of the pha...

The structure of a crystalline material may be described by a crystal lattice structure and the locations of atoms in this lattice. The crystal lattice is a 3-dimensional periodic array that defines the symmetries, i.e. shape, of the crystal. There are seven possible crystal lattices: cubic, hexagonal, tetragonal, rombohedral, orthorhombic, monoclinic and triclinic. When we define the possible ...

A simultaneous low-temperature X-ray powder-diffractometric (XRD)-DSC technique was applied to the solid state and melting process of frozen aqueous solutions of 2-propanol. 1H NMR spectra were also obtained at low temperatures. The chemical shifts of the CH3 proton and the CH proton can be classified into four temperature regions: higher than -20 degrees C, around -20 degrees C, -50 to -20 deg...

Synthesis and structural characterization of two novel symmetrical banana mesogens built from resorcinol with seven phenyl rings linked by ester and imine with a terminal dodecyl/dodecyloxy chain has been carried out. Density functional theory (DFT) has been employed for obtaining the geometry optimized structures, the dipole moments and (13)C NMR chemical shifts. The HOPM and DSC studies revea...

Tracking thermally induced reactions has always been challenging for electrode materials of electrochemical battery systems. Traditionally, a variety of calorimetric techniques and in situ XRD at elevated temperatures has been used to evaluate the thermal stability of electrode materials. These techniques are capable of providing variations in heat capacity, mass and average bulk composition of...

A low-valent trinuclear iron complex with an unusual linear Fe(I)-Fe(II)-Fe(I) unit is presented. It is accessed in a rational approach using a salt metathesis reaction between a new anionic Fe(I) containing heterocycle and FeCl2. Its electronic structure was studied by single crystal XRD analysis, EPR and Mössbauer spectroscopy, and magnetic susceptibility measurements.

The structure-activity relations in the alumina-supported cobalt catalysts are studied at the realistic conditions of Fischer-Tropsch synthesis using in situ time-resolved XRD and catalytic measurements. Cobalt sintering during the first 3-5 h of the reaction and cobalt carbidisation at a longer time on stream (>8 h) coincide with catalyst deactivation.

Molybdenum catalysts carburized in CH4/H2 exhibited activity for methanol electrooxidation (MOR) in half cell measurements. Mo carburized at 773 and 873 K showed high electrooxidation of methanol compared to carburization at other temperatures. Catalyst characterization was carried out by XRD and TPC. The active carbide species responsible to facilitate the MOR was the Mo oxycarbide and –Mo2C s...