Crystal structure of the new silicide LaNi11.8–11.4Si1.2–1.6

The intermetallic compound LaNi11.8–11.4Si1.2–1.6 was synthesized by arc-melting and its crystal structure was determined using powder and single-crystal X-ray diffraction data. The compound adopts the cubic CaCu6.5Al6.5-type structure (space group Fm 3 ‾ $\bar{3}$ c, Pearson code cF112, Z = 8), which is a partially ordered ternary derivative of the NaZn13 type: a = 11.256(4) Å, V = 1426.1(15) Å3, R = 0.0133, wR = 0.0285 for 93 reflections with I > 2 σ(I) for LaNi11.4Si1.6; a = 11.25486(8) Å, V = 1425.68(2) Å3, R p = 4.17%, R wp = 5.85%, R B = 3.44% for LaNi11.8Si1.2. One of its crystallographic positions (96i) is occupied by a mixture of Ni and Si atoms. The structure of this new silicide can be represented as a packing of Ni-centered icosahedra and La-centered snub cubes, which are packed in a CsCl-related manner.

Electronic stabilization by occupational disorder in the ternary bismuthide Li3–x–y In x Bi (x ≃ 0.14, y ≃ 0.29)

A ternary derivative of Li3Bi with the composition Li3–x–y In x Bi (x ≃ 0.14, y ≃ 0.29) was produced by a mixed In+Bi flux approach. The crystal structure adopts the space group Fd\overline{3}m (No. 227), with a = 13.337 (4) Å, and can be viewed as a 2 × 2 × 2 superstructure of the parent Li3Bi phase, resulting from a partial ordering of Li and In in the tetrahedral voids of the Bi fcc packing. In addition to the Li/In substitutional disorder, partial occupation of some Li sites is observed. The Li deficiency develops to reduce the total electron count in the system, counteracting thereby the electron doping introduced by the In substitution. First-principles calculations confirm the electronic rationale of the observed disorder.

Crystal Structure of the New Ternary Antimonide Ho5GaSb3

The crystal structure of the new ternary antimonide Ho5GaSb3 has been determined from X-ray single-crystal data: space group Pnma, a = 7.9667(8), b = 15.128(2), c = 7.9616(8) Å , V = 959.5(3) Å3, Z = 4, RF = 0.059, Rw = 0.066 for 9020 reflections. The crystal structure of Ho5GaSb3 is a ternary derivative of the Sm5Ge4 structure type with partially ordered distribution of gallium and antimony atoms