  The present paper deals with the analysis of experimental results taking into
account mechanisms brought by the bulk elastic energy transformed by the
thermodynamic parameters, temperature, magnetic fields, high hydrostatic
pressure (T-H-P). An effect of the external parameters is considered through
the separation of critical lines and points of the cooling-heating effect in
the course of analysis of linear elastic evolution of properties in sign
alternating and crossing effects of elastic stress energy as well as their
value for structural reorganizations at reversible volume changes (structural
phase transformations of types I and II). An explanation of the direct and
reverse hysteresis effect in the range of the structural phase transitions I
and II is suggested and the secondary signs of changes of phase state
properties in the wide range of structures are formulated. The regularities of
formation of a structural phase transition at 0 K are stated with separating
the position of the triple point and the change of the properties and phase
states with the elements of superconducting and conducting properties.
