R. Eger

Touchless Optical Finger Motion Tracking Based on 2D Nanosheets with Giant Moisture Responsiveness

A new optical touchless positioning interface based on ultrasensitive humidity responsive 1D photonic crystals utilizing the giant moisture dependent swelling capacity of 2D phosphatoantimonate nanosheets is presented. The spatially confined, full spectral color change combined with reversible transparency switching induced by the humidity sheath of a human finger allows for real time, true color lateral finger motion tracking under touchless conditions.

Y7I12C2N: Eine Verbindung aus Einheiten zweier Y6(C2)-Oktaeder und eines Y6N2-Tetraederdoppels / Y7I12C2N: A Compound with Units of Two Y6(C2) Octahedra and a Y6N2 Double Tetrahedron

The new compounds Y7I12C2N and Ho7I12C2N have been prepared by reaction of stoichiometric amounts of the metals (RE), REI3, REN and C in closed Ta capsules at 1150 and 1120K, respectively. Pure samples of the compounds were obtained after 5 days annealing time. The crystals with xenomorphic shape are olive-green (Y7I12C2N) or red-brown (Ho7I12C2N) in colour and sensitive to air and moisture. Y7I12C2N crystallizes in the space group P 1̄ (No. 2) with lattice constants a = 971.24(7), b = 1030.38(7), c = 1673.58(11) pm and α = 101.366(5), β = 92.758(5), γ = 112.799(5)°. According to Guinier photographs Ho7I12C2N is isotypic with the lattice consiants u - 968.8(3), b = 1028.7(3), r. = 1667.8(5) pm and α = 101.31(2), β = 92.78(2), γ = 112.80(1)°. In the structure the C atoms are present as C2 units with a C -C distance of 144 pm. These C2 units are octahedrally coordinated by Y atoms (o1). The N atoms are in the center of Y4 tetrahedra, which are linked via a common edge to form double tetrahedra (t2). By condensation of N-centered double tetrahedra (t2) with a C2-centered Y octahedron (o1) the characteristic units o1t2o1 are formed. The I atoms coordinate all free edges and corners of these units and connect them via Ii - Ia contacts parallel [100] and [001]. The compounds are semiconducting. Ho7I12C2N exhibits Curie-Weiss behaviour with θ = 15(1) K and μeff = 10.5(1) μB.

Structural Stability Diagram of ALnP2S6 Compounds (A = Na, K, Rb, Cs; Ln = Lanthanide)

Thiophosphate compounds have been studied extensively in the past for their rich structural variations and for a large variety of interesting properties. Here, we report 11 new phases with the composition ALnP2S6 (A = Na, K, Rb, Cs; Ln = lanthanide). These new thiophosphates crystallize in four different structure types, with the space groups Fdd2, P1̅, P21, and P21/c, respectively. All phases are insulating and the calculated band gaps range between 3 eV and 3.5 eV. Magnetic measurements on the compounds with open f-shells show paramagnetic behavior and magnetic moments that match the expected free ion values of the respective lanthanide cations. We present a structural stability phase diagram for the ALnP2S6 family of compounds, which reveals a clear relationship between ionic radii and the preferred crystal structure, as well as stability regions to form ALnP2S6-type phases.

Die Bestimmung von Wasserstoff in Metallen, Metallhydriden und Hydridhalogeniden/Determination of Hydrogen in Metals, Metal Hydrides and Hydrid Halides

The hydrogen content in NbH0.177, G d H 2, and the chlorides and brom ides of the type LnXHn (Ln = Y, Gd; 0.67 ≤n≤ 1.00) is determined. The samples are burnt in an oxygen atmosphere and the H2O produced in the combustion process is potentiometrically titrated with an accuracy of ± 3% (Karl-Fischer method).

Copper Selenidophosphates Cu4P2Se6, Cu4P3Se4, Cu4P4Se3, and CuP2Se, Featuring Zero-, One-, and Two-Dimensional Anions

Five new compounds in the Cu/P/Se phase diagram have been synthesized, and their crystal structures have been determined. The crystal structures of these compounds comprise four previously unreported zero-, one-, and two-dimensional selenidophosphate anions containing low-valent phosphorus. In addition to two new modifications of Cu4P2Se6 featuring the well-known hexaselenidohypodiphosphate(IV) ion, there are three copper selenidophosphates with low-valent P: Cu4P3Se4 contains two different new anions, (i) a monomeric (zero-dimensional) selenidophosphate anion [P2Se4](4-) and (ii) a one-dimensional selenidophosphate anion [Formula: see text], which is related to the well-known gray-Se-like [Formula: see text] Zintl anion. Cu4P4Se3 contains one-dimensional [Formula: see text] polyanions, whereas CuP2Se contains the 2D selenidophosphate [Formula: see text] polyanion. It consists of charge-neutral CuP2Se layers separated by a van der Waals gap which is very rare for a Zintl-type phase. Hence, besides black P, CuP2Se constitutes a new possible source of 2D oxidized phosphorus containing layers for intercalation or exfoliation experiments. Additionally, the electronic structures and some fundamental physical properties of the new compounds are reported. All compounds are semiconducting with indirect band gaps of the orders of around 1 eV. The phases reported here add to the structural diversity of chalcogenido phosphates. The structural variety of this family of compounds may translate into a variety of tunable physical properties.

Investigation of the Orbital and magnetic orderings in VF3

We report on a magnetic and structural investigation of layered antiferromagnetic system vanadium (III) fluoride. VF3 crystallizes in a distorted ReO3 structure (R-3c) with rotated undistorted VF6 octahedra. The V3+ cations are arranged in a triangular lattice with the possibility of exhibiting magnetic frustration. Polycrystalline samples of VF3 were investigated using heat capacity, dielectric, magnetic susceptibility, synchrotron and neutron powder diffraction methods. Combining our results, we report the first evidence for a first order phase transition resulting from the ordering of the t2g orbitals below 105-110 K. This transition reduces the symmetry to C2/c. We further confirm that VF3 undergoes a long-range antiferromagnetic order at ∼19 K in accordance with literature [1]. The antiferromagnetic order results in a magnetic structure with the magnetic moments alternating between a parallel and b parallel alignments in the ab plane.