  The structural evolution and superconductivity of a 122-type solid solution
Sr1-xBaxNi2P2 were studied. We found that an orthorhombic-tetragonal structural
phase transition takes place at x = 0.5, and is characterized by the P-P dimers
breaking. The superconducting transition temperature exhibited its highest
value of 2.85 K at x = 0.4.
