New Ternary Zirconium Antimonides, ZrSi0.7Sb1.3, ZrGeSb, and ZrSn0.4Sb1.6: A Family Containing ZrSiS-Type andβ-ZrSb2-Type Compounds

Ternary arsenides Zr(Si As1−)As with PbCl2-type (0 ≤x≤ 0.4) and PbFCl-type (x= 0.6) structures

“…Both are built up of similar Zr-centred monocapped square antiprismatic coordination polyhedra (CN9), although the geometry of this polyhedron in Zr(Si 0.4 As 0.6 )As does not exhibit strictly fourfold symmetry. Unlike the corresponding antimonides Zr(Si x Sb 1−x )Sb (0.07 ≤ x ≤ 0.12; PbCl 2 -type) [6] and Zr(Si 0.7 Sb 0.3 )Sb (PbFCl-type) [4], where there is a clear demarcation between the shorter Zr-(Si/Sb) and longer Zr-Sb distances, the similar sizes of Si and As give rise to a narrower range of Zr-(Si/As) and Zr-As distances (within 2.7-2.9 Å) in the arsenides. These Zr-centred polyhedra are tilted in different directions in Zr(Si 0.4 As 0.6 )As, with the (pseudo)-fourfold axis aligned roughly with [1 0 2] and [1 02], whereas they are oriented along [0 0 1] in Zr(Si 0.6 As 0.4 )As.…”

“…The most well-studied of these systems are the silicon-and germanium-containing antimonides, which comprise the following phases (for Tt = Si, Ge): MTt x Sb 2−x (PbCl 2 -or PbFCl-types) [4][5][6], TiTt x Sb 1−x (NiAs-type) [7], Ti 5 TtSb 2 (W 5 Si 3 -type) [7][8][9], Ti 5 Tt 3−x Sb x (Mn 5 Si 3 -type) [8,9], and Zr 5 TtSb 3 (stuffed Mn 5 Si 3 -type) [10,11]. The tin-containing antimonides tend to be distinct, as exemplified by ZrSn x Sb 2−x (CrSi 2 -or PbCl 2 -types) [4,12], TiSnSb (Mg 2 Cu-type) [13,14], and Ti 11 Sn x Sb 8−x (Cr 11 Ge 8 -type) [15]. In contrast, examples of the other pnictides (Pn = P, As, Bi) have been relatively sparse so far: Hf 27 Si 6 P 10 (own type) [16], Hf(Si 0.5 As 0.5 )As (PbFCltype) [17,18], Zr 5 Sn 3 P or Zr 5 Sn 3 As (stuffed Mn 5 Si 3 -type) [19], and "Ti 3 SnBi" (unknown structure) [20,21].…”

“…A key motivation for examining these systems is to understand mixed-anion compounds that may adopt structures different from the parent binaries because of stabilization through differential fractional site occupancy (DFSO) [1][2][3]. The most well-studied of these systems are the silicon-and germanium-containing antimonides, which comprise the following phases (for Tt = Si, Ge): MTt x Sb 2−x (PbCl 2 -or PbFCl-types) [4][5][6], TiTt x Sb 1−x (NiAs-type) [7], Ti 5 TtSb 2 (W 5 Si 3 -type) [7][8][9], Ti 5 Tt 3−x Sb x (Mn 5 Si 3 -type) [8,9], and Zr 5 TtSb 3 (stuffed Mn 5 Si 3 -type) [10,11]. The tin-containing antimonides tend to be distinct, as exemplified by ZrSn x Sb 2−x (CrSi 2 -or PbCl 2 -types) [4,12], TiSnSb (Mg 2 Cu-type) [13,14], and Ti 11 Sn x Sb 8−x (Cr 11 Ge 8 -type) [15].…”

On the existence of ZrAs2 and ternary extension Zr(GexAs1−x)As (0≤x≤0.4)

“…One interesting outcome from these investigations has been the proposal that "␤-ZrSb 2 " does not exist as a true binary but rather as a Si-stabilized ternary phase, Zr(Si x Sb 1−x )Sb, with a small phase width (0.07 ≤ x ≤ 0.12) adopting the orthorhombic PbCl 2 -type structure [1]. With higher Si content, ZrSi 0.7 Sb 1.3 forms the tetragonal PbFCl-type structure [2]. In both cases, the source of Si is believed to originate from the use of fused-silica tubes as the container material.…”

“…In both cases, the source of Si is believed to originate from the use of fused-silica tubes as the container material. Mixing of other Tt atoms (such as Ge and Sn) is also possible in these antimonides [1,2]. Similar doubts might be cast on the analogous binary PbCl 2 -type zirconium arsenide, ZrAs 2 , which was prepared in fused-silica tubes as well [3,4].…”