Ag2PbO2, Optimierung der Kristallzüchtung und Verfeinerung der Kristallstruktur

Ag₂PbO₂, Optimization of Crystal Growth and Crystal Structure Refinement Large single crystals of Ag₂PbO₂ (1×1×7 mm) suitable for measurements of anisotropic physical properties have been grown. The refinement of the crystal structure (I2/c; crystal size 0.08 × 0.08 × 0.31 mm; a = 6.0775(9), b = 8.704(1), c = 6.553(1) Å, β = 93.545(8)°; Z = 4; 1235 diffractometer data; R = 0.038) confirms the positions of the heavy atoms, and allows for an unambiguous determination of the oxygen coordinates.     

Verfeinerung der Kristallstruktur von K2O2

Refinement of the Crystal Structure of K₂O₂ The crystal structure of K₂O₂ has been refined using 241 diffractometer data (Cmca; a = 6.733(1), b = 6.996(1), c = 6.474(1) Å; Z = 4; R_w = 0.050). The distance O? O (1.541(6) Å) is significantly larger than that one assumed for alkali metal peroxides, so far.     

Untersuchungen in der Reihe der Methyl-1, 2-benzanthrachinone

Ohne Zusammenfassung     

Zur Kenntnis der NMR-Daten der ?O2CCH2S-Gruppe

Magnetic non-equivalence of methylenic protons in compounds of the type HO₂CCH₂SR′ and RO₂CCH₂SR′ were studies and the influence of substitution discussed. Furthermore, it was found that the methylene geminal coupling constant, J_AB, is almost independent of the constitution of the compounds and the solvents used. A variation of the magnetic non-equivalence, Δv, of the methylenic protons with the constitution of the compounds and the solvents used is, however, observed.     

Bestimmung der Art der Wasserbindung im Xonotlit 6 CaO-6 SiO2-H2O

The ¹H-NMR spectra of powdered synthetic xonotlite (5.64 CaO · 6SiO₂ · 1.56 H₂O) at +22 and ?150°C have been recorded. From the line shape the various bonding states of the protons are determined. Per 6 SiO₂ units, 1.46 H₂O are bound in form of OH groups and 0.20 H₂O exist at room temperature as mobile water molecules. By quantitative evaluation it is shown, that the constitution of the examined sample has to be represented by the formula (CaOH)_2.0Ca_3.6(H_0.8Si₆O₁₇). 0.2 H₂O. Line shape analysis provides the possibility to distinguish between CaOH and SiOH protons. The proton-proton distances are calculated, and by comparison with the known X-ray data the positions of the CaOH protons are proposed.     

Nachbargruppenbeteiligungen bei der substitution von 2-amino-2-desoxy-α-d-glucopyranosiden in der 3-stellung

Neighboring group participation severely restricted nucleophilic substitution of N-protected 2-amino-2-deoxy-3-O-mesyl-α-D-glucopyranosides with azide ion. N-acetyl as blocking group led to the formation of the oxazoline $\text{3}$ while from N-dinitrophenylderivatives epimers were formed via the aziridine $\text{11}$.     

Zur Kenntnis der Oxoberyllate der Alkalimetalle [1, 2]

On Oxoberyllates of the Alkali-Metals The existence of the phases K₂Be₂O₃ (2 forms), K₄BeO₃, Rb₂Be₃O₄, Rb₂Be₂O₃,Rb₄BeO₃, Cs₂Be₃O₄ and Cs₂BeO₂ is proved by powder-datas according to GUINIER -SIMON . In single crystal form we obtained Li₄BeO₃ [a = 5.49; b = 9.53; c = 4.93 Å; a = 114.₁; ß = 105.₀; γ = 106.₆°; triclinic], Na₂Be₂O₃ [;a = 6.32; b = 8.53; c = 2.71 Å; α = 107.₇; ß = 105.₅; γ = 78.₄°; triclinic], Na₆Be₂O₅ [a = 5.67₂; c = 10.2₁ Å; tetragonal] as also K₂BeO₂ [a = 7.09₈; b = 10.57₇; c = 5.70₆ Å; γ = 131.₃°; monoclinic] and Rb₂BeO₂ [a = 7.46₃; b = 11.17₀; c = 5.88₁ Å; γ = 131.₈°; monoclinic].     

2-Pyridylhydrazone als Carbonylderivate zur Steuerung der Fragmentierung in der Massenspektrometrie

2-Pyridylhydrazones as Carbonyl Derivatives to induce Fragmentation in Mass Spectrometry It was found that the 2-pyridylhydrazone is a derivative of the carbonyl group, which is able to induce fragmentation of an alicyclic skeleton with an efficiency comparable to that of the tertiary amino group and the ethylene acetal group.     

Untersuchung der Emul-gierwirkung der Blockcopolymeren Polystyrol/Polyvinyl-2-pyridiniumchlorid und Polyisonren/Polyvinyl-2-pyridiniumchlorid

Ohne Zusammenfassung     

Untersuchung der Emul-gierwirkung der Blockcopolymeren Polystyrol/Polyvinyl-2-pyridiniumchlorid und Polyisonren/Polyvinyl-2-pyridiniumchlorid

Ohne Zusammenfassung     

Verfeinerung der Kristallstruktur von SrO2

Refinement of the Crystal Structure of SrO₂ Single crystals of SrO₂ have been obtained after high pressure/high temperature reaction of a SrO/KClO₃ mixture at 20 kbar, 1 400°C. The crystal structure was refined using 154 unique diffractometer data (I4/mmm; a = 3.5626(3), c = 6.6159(6) Å; Z = 2; R = 0.033, R_w = 0.022, S = 0.932). The O O distance (1.493(4) Å) is significantly longer than the one previously assumed. From a refinement of the site occupation factor for oxygen a composition SrO_1.95(2) has been found for the crystal investigated.