Structure, Properties, and Bonding of ZrTe (MnP Type), a Low-Symmetry, High-Temperature Modification of ZrTe (WC Type)

Abstract

ZrTe (MnP) was synthesized by high-temperature methods at 1570 K in Ta ampules. The structure of the telluride was determined by means of single-crystal X-ray diffraction to be orthorhombic, Pnma (No. 62), Z = 4, Pearson Symbol oP8, a = 739.15(15) pm, b = 377.23(8) pm, c = 694.34(14) pm. The orthorhombic MnP type structure is a distorted variant of the NiAs type structure with pronounced metal-metal zigzag chains. Zigzag chains are typical for phases with a d(2) metal atom electron configuration. According to extended Hückel calculations, the homonuclear interactions in the zigzag chains make up for 2/3 of the Zr-Zr interactions in ZrTe (MnP) and contribute decisively to the stability of the structure. The emergence of the distorted MnP type structure instead of the high-symmetry NiAs type ZrTe at high temperatures can be understood as the result of an optimization of homonuclear Zr-Zr interactions arising from states close to the Fermi level. The hexagonal WC type ZrTe transforms above 1438 +/- 5 K into ZrTe (MnP) (DeltaH = 8.3 +/- 1.0 kJ mol(-1)). The phase transition is reversible, although at room-temperature the reverse reaction is kinetically inhibited. Zr5Te4 and Zr5Te6 are the phases next to ZrTe. ZrTe (MnP) exhibits temperature-independent paramagnetic properties (chi(mol) = 0.14 x 10(-3) cm(3) mol(-1)), as typical for a metallic conductor. Resistivity measurements on ZrTe (MnP) imply metallic behavior.

Caesium zirconium uranium pentatelluride, CsZrUTe5

“…Each nearly regular ZrTe 6 octahedron shares faces with two adjacent octahedra to create an unusual infinite [ZrTe 3 2À ] chain. The Zr-Te distances (Table 1) are comparable with those of 2.8771 (7)-3.0426 (8) Å in ZrTe (Ö rlygsson & Harbrecht, 2001).…”

Coexistent three-component and two-component Weyl phonons in TiS, ZrSe, and HfTe

“…We further extended this family by proposing eight compounds (TiS, TiSe, TiTe, ZrS, ZrSe, HfS, HfSe and HfTe), which are isoelectronic and isostructural to ZrTe. Among these compounds, five compounds of TiS, ZrS, ZrSe 0.90 , and Hf 0.92 Se as well as ZrTe were experimentally reported to have the same WC-type structure [100][101][102][103][104][105][106][107]. No any experimental data is available for the remaining four compounds of TiSe, TiTe, HfS, and HfTe.…”

“…Table S1 summarizes all optimized lattice constants as compared with the available experimental data. Among these nine compounds, five compounds of TiS, ZrS, ZrSe 0.90 , and Hf 0.92 Se as well as ZrTe were experimentally reported to have the same WCtype structure [100][101][102][103][104][105][106][107]. Because of no any experimental data available for the remaining four compounds of TiSe, TiTe, HfS, and HfTe, here we have assumed that they also crystallizes in the same WC-type structure.…”

Coexistence of Weyl fermion and massless triply degenerate nodal points

“…The software package OpenMX 27 is employed for most of the first-principles calculations, which is based on the linear combination of psuedo-atomic orbitals. 28 The local or- The experimental crystal structure of WC-type ZrTe has been studied by Örlygsson et al 29,30 and is fully relaxed until the residual forces on each atom is less than 0.001 eV/ Å. The sampling of the Brillouin zone in the self-consistent process is taken as the grid of 12×12×10.…”