13C NMR spectrum of crystalline [Rh(Acac) (CO)2]: A contribution to the discussion on [Rh(Acac) (CO)2] molecular structure in the solid state

13C MAS NMR spectrum of polycrystalline [Rh(Acac) (CO)2] (1) displays separate signals from all 7 carbon atoms: 2 doublets from CO ligand carbons along with 5 singlets from Acac carbons. GIPAW calculation of 13C shielding tensor values also revealed non-equivalence of all carbon atoms in molecule 1 in the anisotropic medium of the crystal lattice. Apparently, the C2v symmetry of molecule 1 is broken owing to the asymmetry of its contacts to the neighboring molecules. For example, the contacts O⋯HC of two CO ligands of molecule 1 to the CH group of the closest molecule in the adjacent stack are markedly different: the distances OH are 2.72 and 4.38 Å, the distances OC are 3.65 and 5.00 Å, the angles OHC are 164.9° and 126.4°

Magnetics Hysteresis Properties and Microstructure of High-Energy (Nd,Dy)–Fe–B Magnets with Low Oxygen Content

Abstract: Magnetic properties and microstructure of high-energy (Nd,Dy)–Fe–B magnets with Dy of no more than 1 wt % prepared via a low-oxygen routine are studied. Oxygen content in magnets does not exceed 0.20 wt %. 0.5 wt %–Dy addition reliably stabilizes the coercivity MHc higher than 13 kOe; in this case, the maximum energy density product (BH)max of magnets is 48.5–49.5 MG Oe. High magnetic hysteresis properties are gained via optimization of chemical and phase compositions of magnets, as well as their microstructure. The grain size of the main Nd2Fe14B phase is approximately 3.5 μm; and according to X-ray analysis, the weight fraction of additional Nd-rich phases (NdOx and Nd2O3) does not exceed 2.5%. Scanning electron microscopy study has demonstrated that in triple junctions of Nd2Fe14B grains there are two types of inclusions (В and С) of the NdOx phase, which significantly differ by their chemical composition. С-phase inclusions with low oxygen content (х ≈ 0.03) are enriched in Fe (40–50 wt %); whereas, В-phase with high oxygen content (х ≈ 0.70) contains 3–5 times less Fe. The angular dependences of coercivity of (Nd,Dy)–Fe–B magnets are presented. © 2021, The Author(s).The work is performed in the framework of state assignment of the Ministry of Education and Science of Russia (theme “Magnet,” No. АААА-А18-118020290129-5)

Temporal and structural genetic variation in reindeer (Rangifer tarandus) associated with the pastoral transition in Northwestern Siberia

Funding Information NordForsk. Grant Number: 76915 ERC Advanced Grant. Grant Numbers: 295458, ESRC ES/, M011054/1 JPI HUMANOR ERC Starting GrantPeer reviewedPublisher PD