Polyelement solid solutions of rare earth compounds

It is reported that two compounds containing several rare earth elements (RE) simultaneously was obtained recently. It is proposed to call them polyelement solid solutions - (PSS). Single crystals of RE hexaborides and RE digallides PSS were obtained, some of their characteristics and features are given. These PSS were obtained by mass crystallization from melts - solutions in Al (hexaborides) and Ga (digallides). PSS hexaborides exhibit a “densification” of their crystal structure when RE atoms are introduced into the base LaB6 crystal lattice. The incorporation is facilitated by the presence of a homogeneity region in RE hexaborides and RE digallides. The stepwise chemical analysis of the recently obtained 6-element PSS of lanthanum hexaborides and digallides shows a high uniformity of the RE distribution along the sample. The complex process of the formation of PSS of hexaborides RE and digallides of RE is analyzed and the possibility of obtaining different groups of PSS is discussed. [Display omitted] •Polyelement solid solutions of RE hexaborides and RE dihallides have been obtained and investigated.•An excellent homogeneity of RE distribution in 6-element hexaboride LnB6 was determined.•The “compaction” of the crystal structure of polyelement LnB6 solid solutions was established.•The microhardness of polyelement LnB6 solid solutions was increased markedly.