Electron structure and physical properties of yttrium group rare earth antimonides

Experimental and calculated properties of rare earth antimonides of the composition Ln4Sb3 (Ln-Gd, Tb, Dy, Ho, Fr, Tm, Yb, Lu) are compared. It has been established, that in the series of rare earth antimonides from Gd4Sb3 to Yb4Sb3 electron spectrum lines contracted, at that, lines of Gd4Sb3 and Lu4Sb3 spectra are wider than those of other compounds by 6-7 eV. Effective charge of metal atoms in Ln16Sb12 fragment (Ln-Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) in the series studied decreases. Judging by calculations in the series Gd4Sb3 → Tm4Sb3 the value of interatomic interaction decreases, and Tm4Sb3 evidently exists only in a high-temperature modification. The change of antimonide physical properties points to the weakening of the existing bonds in the lattice and correlates with the calculated data. Yb4Sb3 is the most stable at Yb valence close to 2, which is confirmed by the experimental data. Taking into account the character of calculational and experimental data changes and correlations between them, some unknown physical properties of Er4Sb3 and Tm4Sb3 are evaluated