Über Alkalihexafluorobismutate(V)

The compounds LiBiF₆ (a = 5.18, c = 13.9₉ Å), NaBiF₆ (a = 5.47, c = 15.1₆ Å), RbBiF₆ (a = 7.71, c = 7.89 Å) and CsBiF₆ (a = 7.93, c = 8.27 Å, hexagonal lattice constants) are rhombohedral. The hexagonal unit cell contains three formula weights. LiBiF₆ and NaBiF₆ are isotypic with LiSbF₆, RbBiF₆ and CsBiF₆ are KOsF₆-isotypes. All compounds are colourless and very moisture sensitive.     

Finite temperature effective potential for the abelian Higgs model to the ordere 4,λ 2

A complete calculation of the finite temperature effective potential for the abelian Higgs model to the ordere ⁴, λ² is presented and the result is expressed in terms of physical parameters defined at zero temperature. The absence of a linear term is verified explicitly to the given order and proven to survive to all orders. The first order phase transition has weakened in comparison with lower order calculation, which shows up in a considerable decrease of the surface tension.     

Notizüber Li2PbO3 und Na2PbO3

The compounds Li₂PbO₃ (α-and β-modification) and Na₂PbO₃ are prepared by heating mixtures of Li₂O₂/PbO₂ resp. Na₂O₂/PbO₂ in a dry oxygen atmosphere. The monoclinic lattice constants are reported.     

Zur Darstellung und Kristallstruktur von RbTlF4 und CsTlF4

Preparation and Crystal Structure of RbTlF₄ and CsTlF₄ RbTlF₄ and CsTlF₄ were synthesized by heating equivalent mixtures of alkaline chlorides or carbonates and Tl₂O₃ under a current of fluorine at 450–500°C. The crystal structure of RbTlF₄ has been determined by single crystal X-ray diffraction methods. The unit cell is orthorhombic with a = 8.252, b = 8.359, c = 6.244 Å (Z = 4); space group: C?Pb2₁a. CsTlF₄ and Tl^ITl^IIIF₄ (“TlF₂”) are isostructural with RbTlF₄. The structure contains layers of 2-dimensionally corner-linked distorted [TlF_4/2F₂]-octahedra, which are connected by rubidium ions.     

Zur Kristallstruktur von Wismutpentafluorid

The crystal structure of BiF₅ was determined from single crystals. BiF₅crystallizes in the tetragonal space group I4/m-C with a = 6.581, c = 4.229 Å. Z = 2. The shortest Bi–F- distances are 1.90 (4×) and 2.11 Å (2×).     

Die Kristallstruktur von Thalliumtrifluorid

The crystal structure of thallium trifluoride The crystal structure of TlF₃ has been determined form single crystal diffraction data. The unit cell is orthorhombic, space group Pnma≠D, with a = 5.825, b = 7.024, c = 4.851 Å, Z = 4. Each Tl has 8 nearest F-neighbours. The Tl–F distances range from 2.09 to 2.49 Å.     

Neue Untersuchungen an quaternären Fluoriden

New Investigations on Quaternary Fluorides For the first time the quaternary fluorides M¹₂M^IILnF₇ (M¹ = Na, Ag; M^II = Ca, Cd; Ln = Er? Lu) had been prepared and examined with with X-ray diffraction. All these compounds crystallize in a cubic face-centered lattice. Colourless single crystals of Na₂CdYbF₇ were obtained and the structure was determined. Na₂CdYbF₇ crystallizes in the space group Fm3M-O⁵_h, No. 225. The single-crystal diffraction data refer to a Defect-Fluorite-Structure. The R-value for 332 observed (29 independend) reflections is 2.2%.     

Quintessential adjustment of the cosmological constant

We construct a time dependent adjustment mechanism for the cosmological "constant" which could be at work in a late Friedmann-Robertson-Walker universe dominated by quintessence and matter. It makes use of a Brans-Dicke field that couples to the evolving standard-model vacuum energy density. Our explicit model possesses a stable late-time solution with a fixed ratio of matter and field energy densities. No fine-tuning of model parameters or initial conditions is required.