Well‐shaped yellow to red transparent single crystals of the phosphide oxides REZnPO (RE = Y, La–Nd, Sm, Gd, Dy, Ho) were synthesized from the elements and ZnO in NaCl/KCl fluxes in sealed silica ampoules. Four structures (NdZnPO type, R3m) were refined from single crystal X‐ray diffractometer data: a = 388.5(2), c = 3032(1) pm, wR2 = 0.0380, 360 F2 values for YZnPO, a = 394.6(2), c = 3071(1) pm, wR2 = 0.0587, 226 F2 values for SmZnPO, a = 392.2(2), c = 3056(1) pm, wR2 = 0.0262, 462 F2 values for GdZnPO, and a = 389.33(6), c = 3030.5(4) pm, wR2 = 0.0453, 217 F2 values for DyZnPO each with 14 variables per refinement. The structures are composed of alternate stacks of (RE3+O2−) and (Zn2+P3−) layers with covalent RE–O and ZñP bonding within and weak ionic bonding between the layers. The zinc and oxygen atoms have slightly distorted tetrahedral coordination by atoms of phosphorus and the rare earth element, respectively. According to the electron precise formulation RE3+Zn2+P3−O2−, these pnictide oxides are transparent in visible light. Susceptibility measurements on β‐CeZnPO, β‐PrZnPO, and GdZnPO reveal Curie‐Weiss paramagnetism with experimental magnetic moments of 2.31, 3.60, and 7.72 μB/RE atoms, respectively. β‐CeZnPO and β‐PrZnPO show antiferromagnetic order with Néel temperatures of 7.4 (Ce) and 2.2 (Pr) K. GdZnPO shows no magnetic ordering down to 2 K. Single crystal absorption spectra measured for REZnPO (RE = Y, La, Pr, Nd, Sm, Dy) in the NIR‐Vis region reveal unexpected variations for the optical band gap of these phosphide oxides. For RE = Pr, Nd, Sm, Dy, Ho f‐f electronic transitions with nicely resolved ligand‐field splittings are observed in the range 6000–20000 cm−1. DFT band structure calculations show similarity between the valence bands of tetragonal and rhombohedral REZnPO as they possess mainly P‐3p character. In both cases, the conduction bands have mainly Zn‐4s character, but a significant contribution of RE‐5d occurs in rhombohedral REZnPO, which is responsible for a smaller optical band gap for the latter compounds. Variations of the energy gaps of tetragonal REZnPO can be explained by hybridization of Zn‐4s + RE‐5d + RE‐4f orbitals for the conduction band. DFT volume optimizations of α‐ and β‐PrZnPO show β‐PrZnPO to be more stable by 10.7 kJ mol−1.
The equiatomic rare earth metal zinc arsenide oxides REZnAsO (RE ϭ Y, LaϪNd, Sm, GdϪEr) were synthesized in well crystallized form from the elements, arsenic, and ZnO in NaCl/ KCl fluxes in sealed silica ampoules. The samples were characterized by powder and single-crystal X-ray data. HoZnAsO and ErZnAsO are reported for the first time. Four structures (ZrCuSiAs type, space group P4/nmm) were refined from single-crystal X-ray diffractometer data: a ϭ 394.23(3), c ϭ 884.0(1) pm, wR2 ϭ 0.0345, 216 F 2 values for YZnAsO, a ϭ 409.56(3), c ϭ 907.0(1) pm, wR2 ϭ 0.0502, 285 F 2 values for LaZnAsO, a ϭ 397.62(4), c ϭ 889.2(2) pm, wR2 ϭ 0.0700, 216 F 2 values for GdZnAsO, and a ϭ 392.72(3), c ϭ 881.5(1) pm, wR2 ϭ 0.0580, 373 F 2 values for * Prof. Dr. R. Pöttgen
Optofluidics is increasingly gaining impact in a number of different fields of research, namely biology and medicine, environmental monitoring and green energy. However, the market for optofluidic products is still in the early development phase. In this manuscript, we discuss modular platforms as a potential concept to facilitate the transfer of optofluidic sensing systems to an industrial implementation. We present microfluidic and optical networks as a basis for the interconnection of optofluidic sensor modules. Finally, we show the potential for entire optofluidic networks.
Ln: Y, La-Nd, Sm, Gd, Dy, Ho). -Single crystals of the title compounds are prepared by reaction of the rare earth metals, ZnO, and red phosphorus in a NaCl/KCl flux (1170 K, evacuated silica tube, 11-24 d). The structures of LnZnPO with Ln: Y, Sm, Gd, and Dy are determined by single crystal XRD (space group R3m, Z = 6). The structures are composed of alternate stacks of (Ln 3+ O 2-) and (Zn 2+ P 3-) layers with covalent Ln-O and Zn-P bonding within and weak ionic bonding between the layers. Susceptibility measurements on β-CeZnPO, β-PrZnPO, and GdZnPO reveal Curie--Weiss paramagnetism with experimental magnetic moments of 2.31, 3.60, and 7.72 μB/Ln atom, respectively. β-CeZnPO and β-PrZnPO show antiferromagnetic ordering with Neel temperatures of 7.4 K and 2.2 K. GdZnPO exhibits no magnetic ordering down to 2 K. Single crystal NIR/Vis absorption spectra measured for the compounds with Ln: Y, La, Pr, Nd, Sm, Dy reveal unexpected variations for the optical band gap of these phosphide oxides. For Ln: Pr, Nd, Sm, Dy, Ho f-f electronic transitions with well resolved ligand-field splittings are observed in the range 6000-20000 cm -1 . -(LINCKE, H.; GLAUM*, R.; DITTRICH, V.; TEGEL, M.; JOHRENDT, D.; HERMES, W.; MOELLER, M. H.; NILGES, T.; POETTGEN, R.; Z. Anorg. Allg.
Lanthanoids I 2800 Structure and Optical Properties of the Arsenide Oxides LnZnAsO (Ln: Y, La-Nd, Sm, Gd-Er). -The title compounds including the new compounds HoZnAsO and ErZnAsO are prepared from 1:1:1 mixtures of the rare earth elements, As, and ZnO in a NaCl/KCl flux (silica ampules, 1120-1170 K, 6-19 d) and characterized by powder and single crystal XRD and by electronic absorption spectroscopy. The compounds crystallize in the tetragonal space group P4/nmm with Z = 2. The structures consist of alternate stacks of [LnO] + and [ZnAs]layers with covalent Ln-O and Zn-As intralayer and weak ionic interlayer bonding. The crystals are transparent with yellow (LaZnAsO) to red color tones. LaZnAsO exhibits a significantly higher optical band gap (≈2.3 eV) than LnZnAsO (Ln: Y, Pr, Nd, Sm; ≈1.9 eV). -(LINCKE, H.; GLAUM*, R.; DITTRICH, V.; MOELLER, M. H.; POETTGEN, R.; Z. Anorg. Allg. Chem. 635 (2009) 6-7, 936-941; Inst. Anorg. Anal. Chem.,
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