Coordination studies of Al-EDTA in aqueous solution.

The degree of aluminum toxicity is based on its complexation with organic ligands. One of these complexes is AlEDTA- (Al = aluminum, EDTA = ethylenediaminetetraacetate), the structure of which in aqueous solution has been debated on the basis of X-ray absorption and NMR measurements with different interpretations proposing different coordination. In addition, there is a lack of consensus regarding the relationship of crystalline AlEDTA- and its geometry in solution.

A nanoscale mechanism of fatigue in ionic solids.

We employ periodic density functional theory to explore the effect of cyclic tensile loading on the behavior of alumina in the threshold region of crack formation. We find evidence for nanoscale fatigue when the alumina lattice is subjected to uniaxial tensile loading and unloading and tensile stresses normal to the applied load. It is possible that such atomic-scale fatigue impacts the durability of ceramics, since the highly ionic bonding requires near-ideal lattice structures in order to maintain cohesive strength.