Highly strained structure of a four-layer deposit of Pd on Ni(110): a coupled theoretical and experimental study.

The structure of a four monolayer deposit of Pd on Ni(110) has been determined by a combination of x-ray diffraction experiments and density-functional theory calculations. This Pd film presents, after annealing at 500 K, a (Nx2) reconstruction associated with a large enhancement of its catalytic activity. The N superstructure, along the dense [11;0] direction, comes from periodic edge dislocations initiated by a vacancy in the first Pd layer. In the perpendicular direction, the doubling of the period originates in a pairing-buckling displacement of the rows. This study evidences a new Pd atoms arrangement with quasi-four-fold hollow sites on the surface, which could play an important role in the exceptional catalytic activity.

Hydrofluoric acid: a review of toxicity.

Hydrofluoric acid is a toxic substance used widely in both industrial and domestic settings. It can cause severe burns, as well as systemic toxicity. Death has been reported from as little as 2.5% body surface area (BSA) burn involving concentrated acid. Topical and parenteral calcium salts have proven effective therapy for both dermal and systemic manifestations. All emergency physicians should be aware of the unique complications and treatment of these injuries.