In recent decades increasing attention has been devoted to high pressure research in
physics and chemistry. Various factors are responsible for this development. High pressure
range means, first of all, the region of behavior where strong intermolecular interaction is
present, due to the increasing numerical density of the particles. This causes several specific
consequences. In gaseous systems, large deviations from ideality and a continuous
approach to liquids may be observed. As a convincing example of this tendency, the …

Kinetic and static methods for creation of thermodynamically active hydrogen are discussed.
High pressure devices for investigation of formation and decomposition equilibria of metallic
systems in the presence of high pressure gaseous hydrogen are described. Furtheron a
high pressure X‐ray device for similar purposes is presented. Details of formation and
decomposition equilibria are discussed for the following systems: Ni‐H, Ni‐D, Cr‐H, Pd‐Rh‐
H, Pd‐Pt‐H, Ni‐Fe‐H, and Pd‐Ag‐H.