Bi Bond Research Articles

An X-ray absorption study of the GeBiSe amorphous system

The amorphous Ge20BixSe80 - x system was studied in the vicinity of the p- to n-type conductivity transition (x = 7 and 13) via measurements of the X-ray Ge K and Bi LIII absorption bands. The analysis, based on a multiple scattering absorption structure calculation, shows that the system consists of clusters of GeSe2, the minimum size of which was estimated. The difference in the Bi LIII absorption bands going from x = 7 to x = 13 implies a change in either the Bi coordination or the size of Bi2Se3 clusters. No evidence for the GeBi bond was found.

Chemical bonding and Bi atom anharmonicity in Ba 0.87K 0.13BiO 3 crystal

The electron density distribution and Bi atom displacements in Ba 0.87K 0.13BiO 3 perovskite single crystal are studied using both X-ray diffraction data and modified statistical method calculations. A noticeable covalent component in the Bi bond with neighboring oxygens is revealed. The nature of the Bi atom anharmonic displacements reflect either dynamic or static instability in its deal crystallographic position. The results obtained indirectly support the interpretation of the nature of incommensurate modulation in Ba 1− x K x BiO 3 crystals under electron irradiation.

Phonon dispersion curves of Ba 0.6K 0.4BiO 3

The lattice dynamics of Ba 0.6K 0.4BiO 3 was investigated inelastic neutron scattering on a superconducting single crystal (T c =26 K (midpoint)). The results were analysed on the basis of a shell model including free carrier screening and a term to account for a breathing deformability of the BiO 6 octahedra. At low frequencies the dispersion curves are very similar to those observed in BaPb 0.75Bi 0.25O .3. However, the screening effects indicate that Ba 0.6K 0.4BiO 3 is more ionic in nature than BaPb 0.75Bi 0.25O 3. The frequencies of the highest LO branches associated with Bi bond stretching vibrations decrease on passing from the Γ-point to the zone boundary.

Organobismuth polymers as X-ray contrast materials: synthesis, characterization and properties

Abstract Organobismuth monomers containing the Ph3Bi moiety were synthesized and polymerized to obtain homogeneous X-ray constrast polymers. Styryldiphenylbismuth (I), α-methylstyryldiphenylbismuth (II), tris(α-methylstyryl) bismuth (III) and (p-diphenylbismuthphenyl)vinyldimethylsilane (IV) were prepared via a Grignard reaction with BiPh2Cl. Monomers I and II are contaminated with significant amounts of Ph3Bi and divinyl compounds. Monomer I can be homo- and copolymerized radically and anionically, II can only be copolymerized, while IV did not polymerize at all. In anionic polymerization the carbanion also attacks the PhBi bond of I and II. Glass transition temperatures were determined as a function of bismuth comonomer content for styrene and acrylate copolymers, and the thermal decomposition was also studied. Radiopacities in millimetres of aluminium per millimetre of polymer were found to be proportional to the molar bismuth content of the transparent copolymer specimens.

Structure of the Bi/InP(110) interface: A photoemission extended x-ray absorption fine-structure study

We studied the Bi/InP(110) interface for 0.35‐ and 0.9‐monolayer (ML) Bi coverages by photoemission extended x‐ray absorption fine‐structure (PEXAFS). P 2p PEXAFS data were acquired. The data were analyzed by Fourier filtering followed by phase analysis using a novel curve‐fitting procedure in which the E0 is also floated. For 0.9‐ML Bi/InP(110), the results show that Bi grows epitaxially and the P–Bi bond length is 2.42±0.05 Å. The first P–In nearest neighbor distance is determined as 2.46±0.05 Å, which is almost equal to the P–In bond length for the clean InP(110) surface and the bond length is 3% contracted in comparison to its value for bulk InP. Note that the surface states for the clean InP(110) surface are pushed out of the band gap due to surface relaxation. Hence, the interface states due to the atomic geometries of the substrate at the interface may not influence Schottky barrier formation to cause Fermi‐level pinning. The P–P and P–Bi bond lengths in the second near‐neighbor distance were determined as 4.17±0.06 and 4.26±0.06 Å, respectively.

Structural and superconducting properties of Bi 2Sr 2(M′ 1−yM y″) 2Cu 3O x(M′=Ca,Y; M″=Na,Ca) including hydrided materials

Structural and superconducting properties of materials of nominal composition Bi 2Sr 2(M′ 1−yM″ y) n−1Cu nO x of the type Bi 2Sr 2(Ca 1−yY y) 2Cu 3O x, Bi 2Sr 2(Y 1−yNa y) 2Cu 3O x and Bi 2Sr 2(Ca 1−yNa y) 2Cu 3O x have been investigated. Mixed phase materials are observed with superconducting onset temperatures as high as T c ~ 107K when M′=Ca, M″=Na. Non-superconducting mixed phase materials are found when M′=Y, M″=Na and y = 0.5 or 0.6. For Bi 2Sr 2(Ca 1−yY y) 2Cu 3O x values of T c for the n = 2 phase decrease with y. They can be partly restored through insertion of H. The results are discussed in terms of stability of the competing Bi 2Sr 2CaCu 2O x phase and modification of bond valence and hole concentration. In particular, a mechanism is discussed based on a lower bond valence than 3 on Bi. Accordingly, Bi can act as a hole reservoir. Partial Y substitution for Ca reduces T c as it increases x and Bi bond valence. H insertion restores the low Bi bond valence and characteristic Cu hole concentration through partial bonding to O.

ChemInform Abstract: Effect of Charge on Bond Formation and Cleavage in Main‐Group‐Transition‐Metal Clusters: The Reactions of Bi2Fe3(CO)9 with [Fe(CO)4]2‐ and [Co(CO)4]‐.

AbstractThe two title reactions proceed quite differently, in one case leading to Bi ‐ Bi bond formation and in the other to Fe ‐ Fe bond cleavage.

Synthesis and structure of a polynuclear complex with a framework consisting of germanium, bismuth and platinum atoms

The structure of the product of the interaction of (C6F5)2GeH2 with Et3Bi has been defined more precisely by X-ray analysis. The heteroelemental framework of this compound is found to be a trigonal bipyramid in which the two apical Bi atoms by three bis(pentafluorophenyl)germyl bridges. The symmetry of the framework isD3h. The average value of the GeBi bond length is 2.739(1) Å. The average values of the GeBiGe and BiGeBi angles are equal to 72.11(4) and 93.94(4)°, respectively.Reaction of the compound with Pt(PPh3)3 yields the unusual 6-nuclear complex [(C6F5)2Ge]3Bi2Pt(PPh3)2. It was shown by an X-ray study that the two Ge, two Bi and Pt atoms form a nonplanar cycle in this complex. Moreover, the Bi atoms are bonded by the (C6F5)2 bridged group. The symmetry of the heavy atom framework is somewhat disordered from Cs. The Pt atom has a square-planar coordination. The GePt and BiPt lengths are equal to 2.466(3) and 2.759(3) Å, respectively. The GeBi bond lengths are changed in the range from 2.695(5) to 2.774(6) Å depending on their positions in the molecule. The GeBiGe angles in the 4-member GeBiGeBi cycle are 87.6(2) and 70.9(2)°, and the BiGeBi angles are 98.3(2) and 98.5(2)°. The GeBiGe angle in the 5-member PtGeBiGeBi cycle is equal to 87.6(2)°, and the GeBiPt angle is 100.8(1)°. The pentafluorophenyl and triphenylphosphine ligands have the usual geometry.

The conformation of triphenylbismuthine and tris-(p-chlorophenyl)bismuthine in benzene solution

Molar Kerr constant, dipole moment, and dielectric relaxation measurements of (p-C6H4Cl)3Bi in benzene solution indicate a C–Bi–C bond angle of 93 ° and an average rotation (in the same sense) of each C6H4Cl group about its C–Bi bond of 45° from a model in which the aromatic planes intersect along the symmetry axis. A similar configuration in solution is likely in the case of Ph3Bi, for which a C–Bi–C bond angle of 94° has been reported in the solid state.