Update on the Combined Analysis of Muon Measurements from Nine Air Shower Experiments

Over the last two decades, various experiments have measured muon densities in extensive air showers over several orders of magnitude in primary energy. While some experiments observed differences in the muon densities between simulated and experimentally measured air showers, others reported no discrepancies. We will present an update of the meta-analysis of muon measurements from nine air shower experiments, covering shower energies between a few PeV and tens of EeV and muon threshold energies from a few 100 MeV to about 10GeV. In order to compare measurements from different experiments, their energy scale was cross-calibrated and the experimental data has been compared using a universal reference scale based on air shower simulations. Above 10 PeV, we find a muon excess with respect to simulations for all hadronic interaction models, which is increasing with shower energy. For EPOS-LHC and QGSJet-II.04 the significance of the slope of the increase is analyzed in detail under different assumptions of the individual experimental uncertainties

Structures of Polymetallaorganosiloxanolates—a Novel Class of Organosilicon Metal Complexes

Single crystal X-ray diffraction studies have revealed the nature and structure of eight types (I–VIII) of polymetallaorganosiloxanolates, representatives of a novel class of the organosilicon metal complexes. Most of the complexes (types I–VII) have sandwich structures with a layer of metal cations between two macrocyclic siloxanolate ligands. In type VIII a single such ligand envelops four inner Cu2+ ions to form a globular species

Molecular Structure of 4,16-dichloro- and 4,16-dibromo[2.2]-Paracyclophanes

Conclusions An x-ray diffraction structural analysis showed that the distortions in the geometries of sterically strained 4,16-dichloro- and 4,16-dibromo[2.2]paracyclophanes are similar to those found in unsubstituted [2.2]paracyclophane. The introduction of bulky halogen atoms at C4 and C16 in the [2.2]paracyclophane molecule does not lead to a marked increase in the steric repulsion of the benzene rings. The polar nature of the halogen atoms leads to dipole-dipole attraction of the antiparallel benzene rings which are drawn somewhat closer to each other and to the halogen atom of the other ring

Macrobicyclic D-Metal Tris-dioximates Obtained by Cross-linking with P-Block Elements. Part VI. Preparation, Molecular Structure and Mössbauer (\u3csub\u3e57\u3c/sub\u3eFe, \u3csub\u3e119\u3c/sub\u3eSn) Parameters of an Iron (II) Complex with a Macrobiocyclic Tin-containing Tris-nioximate Ligand

The tin-containing clathrochelate complex of Fe(II) with cyclohexanedione-1,2-dioxime (nioxime, H2Nx), [FeNx3(SnCl3)2]2- · (Et2NH+ 2)2 · Et2NH2 + · Cl− · 2Pri OH was prepared by slowly adding diethylamine to a solution containing the macrobicyclic [FeNx3(SnCl3)2]2- anion. The structure of the complex has been determined by X-ray methods. Crystal data: monoclinic, space group P21/c, a = 10.565(2), b = 25.413(5), c = 20.198(4)Å, β=95.40(3)°, Z = 4. The iron atoms is encapsulated by the clathrochelate ligand and surrounded by a distorted trigonal antiprismatic coordination sphere comprising by six nitrogen atoms of three dioxime residues. The experimental value of the distortion angle (ca 37.5°) is close to that predicted by the Mössbauer (57Fe) parameters (ca 40°). The average Fe-N bond length of 1.923Å is somewhat greater than that in boron-containing analogues. The Sn atoms have a slightly distorted octahedral coordination, which also correspond to Mössbauer (119Sn) spectroscopic data. The six-membered carbocycles in the dioxime fragments have a half-chair conformation with both β-carbons displaced to the opposite sides of the mid-plane of the remaining atoms. All the active hydrogen atoms of the structure are involved in a hydrogen bond system. The possibilities of use of Mössbauer parameters and their temperature dependences to determine the geometry of iron(II) tris-dioximates and the sign of Δ in Mössbauer (57Fe) spectra are discussed

The Structure of 16, 17β-epoxy-17α-pregn-5-en-3β-ol-20-one Monohydrate

The structure of the title compound (1) has been studied by means of X-ray diffraction. The region of cycleD in epoxide1 was compared with that of the 16,17α-epoxy derivatives of progesterone and pregnenolone (studied previously) as well as with that of the respective 16,17α- and 16,17β-cyclopropano analogs. In contrast to the 16,17α-epoxy-20-oxo derivatives, in compound1 the electron conjugation of the epoxide ring with the CH3CO group at C(17) is partly disrupted. Moreover, the steric congestion at C(17) is significantly less pronounced in 16,17β-epoxide1 than in its 16,17α-counterpart. Both of these factors, especially steric decongestion, are favorable for nucleophilic attack at C(17) in the molecule of1. The X-ray diffraction data do not contradict the previously advanced mechanism of epoxide ring opening in 16,17α- and 16,17β-epoxy-20-oxo steroids by nucleophilic reagents

The Crystal Structure of Peroxydiglutaric Acid

Conclusions The crystal and molecular structure of peroxydiglutaric acid was determined and the approximate isomorphism of this peroxide with the β-form of glutaric acid was revealed. Support was found for our previous hypothesis of the predominant role of crystal structure factors in the inclusion of peroxydicarboxylic acid molecules in the crystal matrix of dicarboxylic acids and their subsequent decomposition into radicals stabilized by this matrix

Formation of H-bonded ionic associates in reactions of 5-nitrosalicylaldehyde with secondary amines

5-Nitrosalicylaldehyde reacts with highly basic secondary aliphatic amines to form molecular complexes of 1 ∶ 1 composition. The complexes with piperidine, diethylamine, dipentylamine, and dibenzylamine (1–4, respectively) have been obtained in the crystalline state and characterized. The X-ray diffraction structural analysis of complex1 demonstrated that it exists in a crystal as an H-bonded dimeric ionic associate [C5H12N+· C7H4NO 4 − ]2 formed as a result of the transfer of the phenyl proton of the aldehyde to the piperidine N atom. According to the results of IR spectroscopy, the other complexes obtained have similar structures