Dataset Information

Phase transition and structures of the twinned low-temperature phases of (Et4N)[ReS4].

ABSTRACT: The title compound, tetraethylammonium tetrathiorhenate, [(C2H5)4N][ReS4], has, at room temperature, a disordered structure in the space group P63mc (Z = 2, ?-phase). A phase transition to the monoclinic space group P21 (Z = 2, ?-phase) at 285?K leads to a pseudo-merohedral twin. The high deviation from the hexagonal metric causes split reflections. However, the different orientations could not be separated, but were integrated using a large integration box. Rapid cooling to 110-170?K produces a metastable ?-phase (P63, Z = 18) in addition to the ?-phase. All crystals of the ?-phase are contaminated with the ?-phase. Additionally, the crystals of the ?-phase are merohedrally twinned. In contrast to the ?-phase, the ?- and ?-phases do not show disorder.

SUBMITTER: Bernhardt E

PROVIDER: S-EPMC7057183 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Phase transition and structures of the twinned low-temperature phases of (Et4N)[ReS4].

Bernhardt Eduard E Herbst-Irmer Regine R

Acta crystallographica. Section C, Structural chemistry 20200207 Pt 3

The title compound, tetraethylammonium tetrathiorhenate, [(C2H5)4N][ReS4], has, at room temperature, a disordered structure in the space group P63mc (Z = 2, α-phase). A phase transition to the monoclinic space group P21 (Z = 2, γ-phase) at 285 K leads to a pseudo-merohedral twin. The high deviation from the hexagonal metric causes split reflections. However, the different orientations could not be separated, but were integrated us ...[more]

PMID: 32132280

Similar Datasets

Project description:A temperature induced valence phase transition from Yb3+ at higher temperatures to Yb2+ at lower temperatures was observed at T = 110(1) K for intermetallic YbPd2Al3. The title compound has been prepared from the elements in sealed tantalum ampoules. The structure was refined from single-crystal data and the title compound was found to crystallize in the hexagonal YNi2Al3 type structure with space group P6/mmm and lattice parameters of a = 929.56(7) and c = 420.16(3) pm (300 K data). Full ordering of the Pd and Al atoms within the [Pd2Al3] ?- polyanion was observed. Magnetic measurements revealed an anomaly in the dc susceptibility data and intermediate valent Yb at higher temperature, as observed from the effective magnetic moment. The proposed valence phase transition was also observed as a ?-type anomaly in heat capacity measurements (T = 108.4(1) K), however, no systematic shift of the ?-peak was observed in field dependent heat capacity measurements. An antiferromagnetic ordering at this temperature, however, could be excluded, based on field-dependent susceptibility measurements and magnetization isotherms. No dynamic phenomenon was observed in ac susceptibility measurements, excluding e.g. spin-glass behavior. Subsequent temperature dependent single-crystal and powder X-ray diffraction experiments indicated a steep increase in the length of the c axis around T = 110 K upon cooling. However, no structural phase transition was found via single-crystal diffraction experiments conducted at 90 K. The anomaly was also observed in other physical measurements of e.g. the electrical resistivity, indicating a clear change in the electronic structure of the material. X-ray photoelectron spectroscopy conducted at room temperature shows the presence of both, Yb2+ and Yb3+, underlining the mixed-valent state. Members of the solid solution Yb1-x Ca x Pd2Al3 (x = 0.33, 0.67, 1) were finally used to further study the charge ordering and the present temperature induced valence phase transition.

Dataset Information

Phase transition and structures of the twinned low-temperature phases of (Et4N)[ReS4].

Publications

Phase transition and structures of the twinned low-temperature phases of (Et<sub>4</sub>N)[ReS<sub>4</sub>].

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets