The MN+1AXN phases: A new class of solids

Anisotropy of the Induced Current Density (ACID), a General Method To Quantify and Visualize Electronic Delocalization

Consistent basis sets of triple-zeta valence with polarization quality for main group elements and transition metals from row one to three have been derived for periodic quantum-chemical solid-state calculations with the crystalline-orbital program CRYSTAL. They are based on the def2-TZVP basis sets developed for molecules by the Ahlrichs group. Orbital exponents and contraction coefficients have been modified and reoptimized, to provide robust and stable self-consistant field (SCF) convergence for a wide range of different compounds. We compare results on crystal structures, cohesive energies, and solid-state reaction enthalpies with the modified basis sets, denoted as pob-TZVP, with selected standard basis sets available from the CRYSTAL basis set database. The average deviation of calculated lattice parameters obtained with a selected density functional, the hybrid method PW1PW, from experimental reference is smaller with pob-TZVP than with standard basis sets, in particular for metallic systems. The effects of basis set expansion by diffuse and polarization functions were investigated for selected systems.

Consistent Gaussian basis sets of triple-zeta valence with polarization quality for solid-state calculations.

The significant and rapid reduction of greenhouse gas emissions is recognized as necessary to mitigate the potential climate effects from global warming. The postcombustion capture (PCC) and storage of carbon dioxide (CO2) produced from the use of fossil fuels for electricity generation is a key technology needed to achieve these reductions. The most mature technology for CO2 capture is reversible chemical absorption into an aqueous amine solution. In this study the results from measurements of the CO2 absorption capacity of aqueous amine solutions for 76 different amines are presented. Measurements were made using both a novel isothermal gravimetric analysis (IGA) method and a traditional absorption apparatus. Seven amines, consisting of one primary, three secondary, and three tertiary amines, were identified as exhibiting outstanding absorption capacities. Most have a number of structural features in common including steric hindrance and hydroxyl functionality 2 or 3 carbons from the nitrogen. Initial CO2 absorption rate data from the IGA measurements was also used to indicate relative absorption rates. Most of the outstanding performers in terms of capacity also showed initial absorption rates comparable to the industry standard monoethanolamine (MEA). This indicates, in terms of both absorption capacity and kinetics, that they are promising candidates for further investigation.

Carbon dioxide postcombustion capture: a novel screening study of the carbon dioxide absorption performance of 76 amines

The hydration reaction is defined as the transfer of an ion or neutral chemical species from the gaseous phase into water, M n+ (g) → M n+ (aq). In this process, water mole- cules bind to metal ions through ion-dipole bonds of mainly electrostatic character. The hy- dration reaction is always strongly exothermic with increa sing heat of hydration with in- creasing charge density of the ion. The structures of the hydrated metal ions in aqueous solution display a variety of configurations depending on the size and electronic properties of the metal ion. The basic configurations of hydrated metal ions in aqueous solution are tetrahedral, octahedral, square antiprismatic, and tricapped trigonal prismatic. This paper gives an overview of the structures of hydrated metal ions in aqueous solution with special emphasis on those with a non-regular coordination figure. Metal ions without d-electrons in the valance shell form regular aqua complexes with a coordination figure, allowing a maxi- mum number of water molecules to be clustered around the metal ion. This number is de- pendent on the ratio of the metal ion radius to the atomic radius of oxygen in a coordinated water molecule (1.34 A). The lighter lanthanoid(III) ions have a regular tricapped trigonal prismatic configuration with the M-O distance to the capping water molecules somewhat longer than to the prismatic ones. However, with increasing atomic number of the lan- thanoid(III) ions, an increasing distortion of the capping water molecules is observed, result- ing in a partial loss of water molecules in the capping positions for the heaviest lanthanoids. Metal ions with d 4 and d 9 valance shell electron configuration, as chromium(II) and cop- per(II), respectively, have Jahn-Teller distorted aqua complexes. Metal ions with low charge and ability to form strong covalent bonds, as silver(I), mercury(II), palladium(II), and plat- inum(II), often display distorted coordination figures due to the second-order Jahn-Teller ef- fect. Metal ions with d 10 s 2 valence shell electron configuration may have a stereochemically active lone electron pair (hemi-directed complexes) or an inactive one (holo-directed). The hydrated tin(II), lead(II), and thallium(I) ions are hemi-directed in aqueous solution, while the hydrated bismuth(III) ion is holo-directed. The structures of the hydrated cationic oxo- metal ions are reported as well.

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Hydrated metal ions in aqueous solution: How regular are their structures?

/pdf/stability-constants-of-copper-ii-zinc-manganese-ii-calcium-c6c5i3ms72.pdf

Stability Constants of Copper(II), Zinc, Manganese(II), Calcium, and Magnesium Complexes of N-(Phosphonomethyl)glycine (Glyphosate).

/pdf/the-temperature-factor-parameters-of-some-transition-metal-1i4kwsirrh.pdf

The Temperature Factor Parameters of Some Transition Metal Carbides and Nitrides by Single Crystal X-Ray and Neutron Diffraction.

/pdf/molecular-structure-of-gaseous-pyrimidine-sujph6il27.pdf

Molecular structure of gaseous pyrimidine

/pdf/phase-transitions-in-mnas-1ul726x2lj.pdf

Phase Transitions in MnAs.

/pdf/the-crystal-structure-of-hexaaqua-tri-mu-hydroxo-mu3-oxo-df1rmnpc6h.pdf

Cha-On Pontchour

Papers

Stability Constants of Copper(II), Zinc, Manganese(II), Calcium, and Magnesium Complexes of N-(Phosphonomethyl)glycine (Glyphosate).

The Temperature Factor Parameters of Some Transition Metal Carbides and Nitrides by Single Crystal X-Ray and Neutron Diffraction.

Molecular structure of gaseous pyrimidine

Phase Transitions in MnAs.

The Crystal Structure of Hexaaqua-tri-mu-hydroxo-mu3-oxo-triuranyl(VI) Nitrate Tetrahydrate, [(UO2)3O(OH)3(H2O)6]NO3.4H2O.