On the change of critical parameters for Zrsub(x)Hfsub(1-x)Vsub(2) system

An attempt is taken to relate the extremal character of concentration dependences of electron and lattice properties of Zrsub(x)Hfsub(1-x)Vsub(2) compounds with peculiarities of their crystal structure. The crystal lattice parameters a and critical temperatures Tsub(c) of transition into the superconducting stage of the compound series Zrsub(x)Hfsub(1-x)Vsub(2) (x = 0.5; 0.25; 0.50; 0.50; 0.75; 1.00) with the C3-15 structure are measured. The a(x) dependence has a linear character, a maximum in the Tsub(c)(x) curve is observed at x approximately 0.50. It is shown that the extremal character of the Tsub(c) concentration dependence and the structure change of the low-temperature modifications of the Zrsub(x)Hfsub(1-x)Vsub(2) at x approximately 0.5 is connected with the change of the type of a topological lattice instability