Peculiarities of component interaction in {Gd, Er}–V–Sn Ternary systems at 870 K and crystal structure of RV6Sn6 stannides

The phase equilibria in the Gd–V–Sn and Er–V–Sn ternary systems were studied at 870 K by means of X-ray and metallographic analyses in the whole concentration range. Both Gd–V–Sn and Er–V–Sn systems are characterized by formation of one ternary compound at investigated temperature, with stoichiometry RV6Sn6 (SmMn6Sn6-type, space group P6/mmm, a = 0.55322(3) nm, c = 0.91949(7) nm for Gd, a = 0.55191(2) nm, c = 0.91869(8) nm for Er). Solubility of the third component in the binary compounds was not observed. Compounds with the SmMn6Sn6-type were also found with Dy, Ho, Tm, and Lu, while YV6Sn6 compound crystallizes in HfFe6Ge6 structure type. All investigated compounds are the first ternary stannides with rare earth elements and vanadium.

► {Gd, Er}–V–Sn ternary systems at 870 K are characterized by formation of stannides with general compositions RV6Sn6. ► Isostructural RV6Sn6 compounds were also found with Y, Dy, Ho, Tm, and Lu. ► The crystal structure of RV6Sn6 compounds was determined by powder diffraction method. ► Structural analysis showed that RV6Sn6 compounds (R = Gd, Dy–Tm, Lu) are disordered; YV6Sn6 is characterized by structure ordering.