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 d2 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) (ΔH = 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 (χmol = 0.14 × 10-3 cm3 mol-1), as typical for a metallic conductor. Resistivity measurements on ZrTe (MnP) imply metallic behavior.
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