Yb_2+3—xPd_12—3+xP₇ (x = 0.40): Different Ytterbium Species in a Substituted Structural Motif of the Zr₂Fe₁₂P₇ Type

Abstract

The new compound Yb2+3—xPd12—3+xP7 x = 0.40(4)) was synthesized by sintering of a mixture of elemental components at 1100 °C with subsequent annealing at 800 °C. The crystal structure of Yb2+3—xPd12—3+xP7 was solved and refined from X‐ray single‐crystal diffraction data: space group P6¯, a = 10.0094(4)Å, c = 3.9543(2)Å, Z = 1; R(F) = 0.022 for 814 observed unique reflections and 38 refined parameters. The atomic arrangement reproduces a structure motif of the hexagonal Zr2Fe12P7 type in which one of the transition metal positions is substituted predominantly by ytterbium (Yb : Pd = 0.86(1) : 0.14). The ytterbium atoms are embedded in the 3D polyanion formed by palladium and phosphorus atoms. Two different environments for ytterbium atoms are present in the structure. Magnetic susceptibility measurements and XAS spectroscopy at the Yb LIII edge show the presence of ytterbium in two electronic configurations, 4ƒ13 and 4ƒ14. The following model was derived. Ytterbium atoms in the 3k site are in the 4ƒ13 state, the two remaining positions contain ytterbium in intermediate‐valence states, giving totally 79 % ytterbium in the 4ƒ13 electronic configuration.

New Scandium Platinum Silicides: ScPt2Si with ‘Inverse’ MgCuAl2 Structure and Sc5Pt9Si7, a Variant of the Zr2Fe12P7‐Type

“…Sc 5 Pt 9 Si 7 is not the first compound, in which a substitution of transition metal atoms on this special 3k site by the more electropositive component is observed, but it is the first example of a complete substitution, and it is the first silicide with a Zr 2 Fe 12 P 7 derivative structure. Examples of substitution to a small extent are the compounds Mg 2.5 Ni 11.5 P 7 , Ca 2.1 Ni 11.9 P 7 , and Ca 2.3 Ni 11.7 As 7 [18], while in Yb 2+3-x Pd 12-3+x P 7 with (x=0.40) the substitution is nearly complete [19]. With regard to these examples, a statistical distribution of scandium and platinum atoms on the 3k site of Sc 5 Pt 9 Si 7 could also be possible.…”

New ternary phosphides RE5Pd9P7 (RE=Tm, Lu): synthesis, crystal and electronic structure

“…The unit cell of the Tm 5 Pd 9 P 7 refined from powder X‐ray diffraction at room temperature indicates no inhomogeneity. However, there is a possibility for the existence of a small region of homogeneity for this phosphide, caused by possible non‐stoichiometry, as it was found for the phosphide Yb 2+3‐ x Pd 12‐3+ x P 7 ( x =0.4) [21] . This question may be the task of further research.…”

“…So, the crystal structure of the new phosphide crystallizes closely to the Yb 2+3‐ x Pd 12‐3+ x P 7 ( x =0.4) type structure; [21] however, it is characterized by a completely ordered arrangement of the all atom types in crystallographic sites. The unit cell of the Tm 5 Pd 9 P 7 refined from powder X‐ray diffraction at room temperature indicates no inhomogeneity.…”

“…However, there is a possibility for the existence of a small region of homogeneity for this phosphide, caused by possible non-stoichiometry, as it was found for the phosphide Yb 2 + 3-x Pd 12-3 + x P 7 (x = 0.4). [21] This question may be the task of further research.…”

“…Only the ternary phosphide Yb 2 + 3x Pd 12-3 + x P 7 (x = 0.4) with the crystal structure closely related to the hexagonal Zr 2 Fe 12 P 7 -type was reported. [21] The atomic arrangement in the Yb 2 + 3-x Pd 12-3 + x P 7 (x = 0.4) structure exhibit a structural motif of the Zr 2 Fe 12 P 7 -type in which one of the transition metal atom positions is partially substituted by Pd atoms.…”