Techniques for direct experimental evaluation of structure-transport relationships in disordered porous solids.

Determining structure-transport relationships is critical to optimising the activity and selectivity performance of porous pellets acting as heterogeneous catalysts for diffusion-limited reactions. For amorphous porous systems determining the impact of particular aspects of the void space on mass transport often requires complex characterization and modelling steps to deconvolve the specific influence of the feature in question. These characterization and modelling steps often have limited accuracy and precision.

Combining mercury thermoporometry with integrated gas sorption and mercury porosimetry to improve accuracy of pore-size distributions for disordered solids.

The typical approach to analysing raw data, from common pore characterization methods such as gas sorption and mercury porosimetry, to obtain pore size distributions for disordered porous solids generally makes several critical assumptions that impact the accuracy of the void space descriptors thereby obtained. These assumptions can lead to errors in pore size of as much as 500%. In this work, we eliminated these assumptions by employing novel experiments involving fully integrated gas sorption, mercury porosimetry and mercury thermoporometry techniques.

Improving sensitivity and accuracy of pore structural characterisation using scanning curves in integrated gas sorption and mercury porosimetry experiments.

Gas sorption scanning curves are increasingly used as a means to supplement the pore structural information implicit in boundary adsorption and desorption isotherms to obtain more detailed pore space descriptors for disordered solids. However, co-operative adsorption phenomena set fundamental limits to the level of information that conventional scanning curve experiments can deliver. In this work, we use the novel integrated gas sorption and mercury porosimetry technique to show that crossing scanning curves are obtained for some through ink-bottle pores within a disordered solid, thence demonstrating that their shielded pore bodies are undetectable using conventional scanning experiments.

NMR studies of cooperative effects in adsorption.

The conversion of gas adsorption isotherms into pore size distributions generally relies upon the assumption of thermodynamically independent pores. Hence, pore-pore cooperative adsorption effects, which might result in a significantly skewed pore size distribution, are neglected. In this work, cooperative adsorption effects in water adsorption on a real, amorphous, mesoporous silica material have been studied using magnetic resonance imaging (MRI) and pulsed-gradient stimulated-echo (PGSE) NMR techniques.

Intermolecular magnetic couplings in the dinuclear copper(II) complex mu-chloro-mu-[2,5-bis(2-pyridyl)-1,3,4-thiadiazole] aqua chlorocopper(II) dichlorocopper(II): synthesis, crystal structure, and EPR and magnetic characterization.

Mu-chloro-mu-[2,5-bis(2-pyridyl)-1,3,4-thiadiazole] aqua chlorocopper(II) dichlorocopper(II) is the first characterized dimeric complex of a transition metal and this hetero ligand [C(12)H(10)Cl(4)Cu(2)N(4)OS; triclinic; space group P; a = 9.296(3) A, b = 9.933(3) A, c = 10.

2-Aminoanilinium phosphite.

The solid-state structure of the title compound, alternatively called 2-aminoanilinium hydrogen phosphonate, C(6)H(9)N(2)(+).H(2)PO(3)(-), shows the monoprotonated diamine molecule to be multiply hydrogen bonded to HPO(3)H(-) anions. There is no inter-phosphite hydrogen bonding, contrary to previous solid-state observations of the species.

Dipotassium tristrontium dimanganese tris(diphosphate).

The structure of the title mixed trimetallic diphosphate, K(2)Sr(3)Mn(2)(P(2)O(7))(3), is constructed of a three-dimensional matrix composed of SrO(8-10), MnO(5) and PO(4) polyhedra. The sharing of O atoms between these polyhedra creates tunnels of large dimensions parallel to (010), in which are found columns of K(+) ions. Thus, the presence of several cations differing in size in the solid matrix leads to the formation of large tunnels and potential conductivity.

Sodium silver tricobalt bis(diphosphate) and sodium silver copper(II) diphosphate.

The crystal structures of two new diphosphates, sodium silver tricobalt bis(diphosphate), (Na(1.42)Ag(0.58))Co(3)(P(2)O(7))(2), and sodium silver copper(II) diphosphate, (Na(1.

NaMn(6)(P(2)O(7))(2)(P(3)O(10)) and KCd(6)(P(2)O(7))(2)(P(3)O(10)).

The crystal structures of two new diphosphates, sodium hexamanganese bis(diphosphate) triphosphate, NaMn(6)(P(2)O(7))(2)(P(3)O(10)), and potassium hexacadmium bis(diphosphate) triphosphate, KCd(6)(P(2)O(7))(2)(P(3)O(10)), confirm the rigidity of the M(6)(P(2)O(7))(2)(P(3)O(10)) matrix (M is Mn or Cd) and the relatively fixed dimensions of the tunnels extending in the a direction of the unit cell. The compounds are isomorphous; the P(2)O(7)(4-) anion and the alkali metal cations lie on mirror planes. Bond-valence analysis of the bonding details of the atoms found within the tunnels permits a prediction of the conductivity.

Dilithium barium diphosphate.

The crystal structure of the novel title diphosphate, Li(2)BaP(2)O(7), exists with a three-dimensional lattice composed of BaO(9) polyhedra linked to corner- and edge-sharing P(2)O(7) diphosphate groups, forming layers parallel to the (010) plane, the layers being linked by P[bond]O[bond]Ba bridges. Tunnels thus created between the layers are occupied by Li(+) cations, two of which lie on twofold axes.

Barium tetraphosphate.

The structure of the low-temperature form of barium tetraphosphate, Ba(3)P(4)O(13), shows the tetraphosphate to exist in an S conformation.