The very first thorough investigation of the rare earth borosulfates RE2[B2(SO4)6] with RE = Y, La–Nd, Sm, Eu and Tb–Lu focusses on synthetic aspects and especially optical properties.
The FLP-mesityl azide addition products 5, formed by FLP-addition to the terminal azide nitrogen atom, undergo N-N bond cleavage in an unusual variant of the Staudinger reaction upon thermolysis or photolysis to give an internally borane stabilized [P]=NH phosphinimine and a dimethylindazole derivative.
We have synthesized two new Eu-based compounds, EuSr2Bi2S4F4 and Eu2SrBi2S4F4 which are derivatives of Eu3Bi2S4F4, an intrinsic superconductor with Tc = 1.5 K. They belong to a tetragonal structure (SG: I4/mmm, Z = 2), similar to the parent compound Eu3Bi2S4F4. Our structural and 151 Eu Mössbauer spectroscopy studies show that in EuSr2Bi2S4F4, Eu-atoms exclusively occupy the crystallographic 2a-sites. In Eu2SrBi2S4F4, 2a-sites are fully occupied by Eu-atoms and the other half of Eu-atoms and Sr-atoms together fully occupy 4e-sites in a statistical distribution. In both compounds Eu atoms occupying the crystallographic 2a-sites are in a homogeneous mixed valent state ~ 2.6 -2.7. From our magnetization studies in an applied H 9 Tesla, we infer that the valence of Eu-atoms in Eu2SrBi2S4F4 at the 2a-sites exhibits a shift towards 2+. Our XPS studies corroborate the occurrence of valence fluctuations of Eu and after Ar-ion sputtering show evidence of enhanced population of Eu 2+ -2 states. Resistivity measurements, down to 2 K suggest a semi-metallic nature for both compounds.
We report the 119 Sn and 7 Li solid-state nuclear magnetic resonance (NMR) spectroscopic characterization of all thermodynamically stable intermetallic phases of the binary Li−Sn system. The isotropic 119 Sn shifts (sum of the isotropic chemical and hyperfine shifts) of the Li−Sn intermetallics are found to be spread over a broad spectral range from 7300 to −500 ppm, allowing a clear Li−Sn phase identification. DFT calculations showed that the hyperfine interaction (Fermi-contact and spin-dipole contributions) constitutes the major 119 Sn magnetic shielding contribution for the Sn-rich Li−Sn intermetallics, which is significantly reduced for Li−Sn intermetallic phases with low and intermediate Sn-content. A full characterization of the effective 119 Sn magnetic shielding anisotropies for all Li−Sn intermetallic phases was achieved using the static broad-band 119 Sn Wideline Uniform Rate Smooth Truncation (WURST) Carr−Purcell−Meiboom−Gill (WCPMG) NMR experiment. These experiments further highlight the potential of the WCPMG NMR technique as it enables the acquisition of the full spectral range observed for the Li−Sn intermetallic phases in a single, static NMR experiment (B 0 up to 7 T), where information about crystallinity and local ordering is directly available from the 119 Sn NMR lineshapes. Such structural fingerprinting possibilities are clear advantages when compared to 7 Li NMR that will be of interest for studies of Sn-containing active materials in lithium-ion-based batteries, allowing a clear distinction between amorphous and crystalline (de)lithiation products in addition to the possibility to probe for amorphization during (dis)charge processes.
The indide EuPtIn2 (MgCuAl2 type, Cmcm, a = 448.23(4), b = 1068.64(11), c = 784.09(8) pm, wR2 = 0.0432, 466 F2 values, 16 variables) was synthesized by induction-melting of the elements and subsequent annealing.
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