The principal possibility of sulphide transfer in phases based on BaZrS₃ and MLn₂S₄ has been considered. The regions of solid solutions based on tertiary compounds have been defined. The systematic study of these phases by methods of conductometry, EMF in chemical concentration chains with and without transfer, potentiostatic chronoamperometry has been performed. A possible defect forming mechanism at consecutive alloying of the tertiary sulphides by the binary ones has been suggested.