Ceria is an interesting component for a variety of catalytic and fuel cell applications. In the study described here, ten different commercial ceria samples as well as synthesized ceria samples were investigated in detail regarding their (defect) structure and characteristic properties using XRD, N2 adsorption–desorption, and optical spectroscopy (Raman, DRIFTS, UV–vis). The investigations revealed correlations of surface defect features (Raman, DRIFTS) as well as those of bulk defects (Raman, UV–vis). The Raman feature at around 250 cm–1 was demonstrated to be related to surface defects rather than a 2TA vibration as described in the literature. A correlation between UV–vis band gap values and the presence of Raman bulk defects was established based on the observed decrease of the band gap energy with increasing number of defects. Detailed Raman analysis revealed that the frequently mentioned linear equation for the determination of the crystal size from the half-width of the F 2g Raman feature is erroneous, since the F 2g half-width depends on ceria bulk defects. Apart from these universal observations, differences in the properties depending on synthesis conditions were observed. In particular, it is shown that the type and quantity of ceria defects are influenced not only by crystal size but also by the preparation method.

FeNC catalysts are the most promising substitutes for Pt‐based catalysts for the oxygen reduction reaction in proton exchange fuel cells. However, it remains unclear which FeN4 moieties contribute to the reaction mechanism and in which way. The origin of this debate could lie in various preparation routes, and therefore the aim of this work is to identify whether the active site species differ in different preparation routes or not. To answer this question, three FeNC catalysts, related to the three main preparation routes, are prepared and thoroughly characterized. Three transitions A–C that are distinguished by a variation in the local environment of the deoxygenated state are defined. By in situ 57Fe Mössbauer spectroscopy, it can be shown that all three catalysts exhibit a common spectral change assigned to one of the transitions that constitutes the dominant contribution to the direct electroreduction of oxygen. Moreover, the change in selectivity can be attributed to the presence of a variation within additional species. Density functional theory calculations help to explain the observed trends and enable concrete suggestions on the nature of nitrogen coordination in the two FeN4 moieties involved in the oxygen reduction reaction of FeNC catalysts.

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Charge density analysis reveals multi-centre bonds in the cluster, hydrogen bridges in the ammonia network, and the dihydrogen bond between H(delta-) and H(delta+); all observed in one compound, [Li(NH3)4]2B6H6.2NH3.

Decahydro-closo-decaborates / Simulated annealing / Powder diffraction structure analysis / X-ray diffraction Abstract. Alkali metal decahydro-closo-decaborates M 2 [B 10 H 10 ] (M ¼ Na, K, Rb) were synthesised by ionexchange and characterised via infrared and 11 B-NMR spectroscopy. The crystal structures of Na 2 [B 10 H 10 ], K 2 [B 10 H 10 ], and Rb 2 [B 10 H 10 ] were determined from X-ray powder diffraction data using real-space techniques. The compounds crystallise in the monoclinic space group P2 1 /n (no. 14) with the lattice constants: Na 2 [B 10 H 10 ]: a ¼ 1028.28 (6) pm, b ¼ 1302.18(5) pm, c ¼ 667.34(3) pm, b ¼ 93.754(3) ; K 2 [B 10 H 10 ]: a ¼ 1285.54(8) pm, b ¼ 1117.84(7) pm, c ¼ 682.27(4) pm, b ¼ 93.357(3) ; Rb 2 [B 10 H 10 ]: a ¼ 1320.04(7) pm, b ¼ 1136.88(6) pm, c ¼ 704.23(4) pm, b ¼ 94.158(3) . The hydroborate anions are arranged almost hexagonally with alkali metal cations in the tetrahedral interstices.

For N(C(4)H(9))(4)B(6)H(7) a proton is shown to be localised above one of the faces of the distorted octahedron, and rhomboid rings are formed as shown by topological analysis of charge densities.

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Three rat BV13S1 alleles (T-cell receptor beta-chain variable gene 13) were characterized by new BV13S1-allele specific monoclonal antibodies (18B1 and 17D5) and sequence analysis of expressed and genomic BV13S1. Two alleles were functional and designated BV13S1A1 present in strains LEW, BUF, PVG, and BV13S1A2 present in BN and WF. Their products differed by six amino acids, two of them in complementarity-determing region (CDR)1 and one in CDR2. A third nonfunctional allele, BV13S1A3P, was found in strains F344 and DA. Apart from a single nucleotide insertion, it was identical to BV13S1A2. All 12 rat strains tested showed association of TCRBC1 with BV8S2/4 alleles but not with the BV13S1 alleles, which may reflect a different gene order of the rat BV compared to mouse. BV13S1A1-encoded T-cell receptors (TCRs) which bind both monoclonal antibody (mAb) 18B1 and mAb 17D5 are over-represented in the CD4 lymphocyte subset. BV13S1A2-encoded TCRs which are stained by mAb 18B1 but not by mAb 17D5 show a slight CD8-biased expression. Preferential usage of BV13S1A1-positive TCRs by CD4 but not by CD8 cells in (LEW x WF)F1 hybrids and cosegregation of BV13SA1 and increased frequency of BV13S1 TCR-positive CD4 cells in a (LEW x BN)x BN backcross suggest structural differences of the two allelic products as the reason for their contrasting CD4/CD8 subset bias.