The book is devoted to the preparation of new varison semiconductor (Ge2)1-x(ZnSe)x , (GaAs)1-x(ZnSe)x , (GaAs)1-x-y(Ge2)x(ZnSe)y, Si1-xGex solid solutions and Ge¬- (Ge2)1-x(ZnSe)x , GaAs - (Ge2)1-x(ZnSe)x , Ge¬- (GaAs)1-x(ZnSe)x, GaAs ¬- (GaAs)1-x(ZnSe)x , Ge - (GaAs)1-x-y(Ge2)x(ZnSe)y, GaAs - (GaAs)1-x-y(Ge2)x(ZnSe)y , Si-Si1-xGex -(Ge2)1-x(GaAs)x structures possessing specific photovoltaic and electrophysical properties based on elements of the fourth group of the periodic system and chemical compounds of A3 B5 , A2 B6 class. With the help of the theoretical formula the prediction of their pairs forming crystalline perfect solid solutions is made.