The synthesis and the spectroscopic characterization of fluoride-alkoxides of niobium and tantalum in the highest oxidation state are reported. Suspensions of MF(5) (M = Nb, Ta) in a chlorinated solvent reacted with up to three equivalents of ROSiMe(3) (R = Me, Et, Ph) to afford polynuclear derivatives and variable amounts of FSiMe(3). Thus MF(4)(OR) (R = Et, Ph) and MF(3)(OR)(2) were obtained ...

Single crystals of {FeHo(6)}I(12)Ho were obtained during the reaction of HoI(3) with metallic holmium and iron in a sealed tantalum container. The crystal structure consists of isolated holmium clusters encapsulating a single Fe atom, {FeHo(6)} ( symmetry). The rare earth metal atoms are surrounded by 12 edge-capping and six terminal iodide ligands that either connect the clusters to each other...

Tantalum oxide honeycomb nanostructures (THNS) were fabricated by electrochemical anodisation of tantalum in H2SO4-HF medium. XRD analysis showed that annealing of THNS at 400 °C improves the crystallinity. HRSEM and AFM results illustrated that nanopores with an average diameter of 30 nm were uniformly distributed and the pore size reduced to 24 nm and 18 nm during subsequent electrodeposition...

Balloon expandable stents can be used to treat coronary stenosis. During stent implantation, X-ray imaging is used. In order to assist the doctors, it was decided to improve the cardiovascular stents’ X-ray absorption ability by placing a unique marker in the stent strut. Tantalum powder, with 98% purity and 3-10 μm grains diameter, was used as the stent integrated marker. The stents were laser...

Recently, titanium-tantalum alloys have been studied as implant materials for dental and orthopedic surgery. However, titanium and tantalum are difficult to mix by common arc melting and induction melting, because of their high melting point and the marked difference between their densities (Ti: 1,680 degrees C, 4.5 g/cm3, Ta: 2,990 degrees C, 16.6 g/cm3). Thus, the Cold Crucible Levitation Mel...

The physical vapor deposition process of serial bideposition is adapted to the fabrication of uniaxial optical coatings. During the coating process the vapor impinges at an angle of incidence of about 70 on to the substrate, and a stepwise axial rotation with 90 increments causes a columnar structure to grow normal to the substrate. Symmetry considerations that follow from the choice of 90 for ...