Niobium hydrides

Thus, the niobium hydrides in fact do exhibit the desired hydridic character they can reduce acetone but cannot react with CO reduction products. From the color, the absence of any NMR, and the formation of 1 mol of free cyclo-pentadiene, the niobium-containing product appears to be a monocyclopenta-dienyl Nb(IV) complex. The rather facile removal of one of the Cp groups appears somewhat surprising but has been observed in related systems. For example, alcoholysis of Cp2TiCl2 gives CpTiC OEt) plus cyclopentadiene, even at room temperature (26). 

Toxicity data on niobium and its compounds are sparse. The most common materials, e.g., niobium concentrates, ferroniobium, niobium metal and niobium alloys, appear to be relatively inert biologically. Limited animal experiments show high toxicity for some salts, which arc related to disturbance of enzyme action, Niobium hydride lias moderate fibiogenic and general toxic action. Recommended maximum allowable concentrations arc 6 mg/m3. Recommended maximum permissible concentration of Nb ill reservoir water is 0.01 mg/L. The threshold for affecting clarity and biological oxygen demand (BOD) is 0.1 mg/L. 

Fire fighting procedures for niobium and niobium hydride powder, suggest letting the fire burn itself out. Small fires can be controlled by smothering with dry table salt or using Type D dry powder fireextinguishing material. Under no circumstances should water be used, as a violent explosion may result. 

Stoll ME, Majors TJ, Elimination of magnetic-susceptibility broadening in NMR using magic-angle sample spinning to measure chemical shifts in niobium hydride (NbHx), J. Phys. Rev. B, 24 2859-2862, 1981. 

The heterocumulene compound p-tolyl isothiocyanate and the thioke-tenes, S=C=CR2 (R2 = Me2(CH2)3CMe2, Bu 2), react with niobium hydride complexes, [NbHCp2(CO)] and [NbH3Cp2], to give insertion products 146 (/ O) and 147 (/2/). 

A new dynamical aspect based on previous work by V. F. Sears [Sears 1984] and G. I. Watson [Watson 1996] was introduced to the data interpretation by the work of E. B. Karlsson et al. [Karlsson 1999] on niobium hydride. While the cross section anomalies found in the previous work [Chatzidimitriou-Dreismann 1997 (a) Chatzidimitriou-Dreismann 1999] were independent of the ex-... 

Therefore, as concerns the determined areas from the VESUVIO data, the argument of Cowley does not play any role and the associated sub-femtosecond quantum entanglement effect found in the metallic hydride is not affected at all. The above results demonstrate that the short-lived quantum entanglement effect revealed in the niobium hydride system [Karlsson 1999 Abdul-Redah 2000 Karlsson 2003 (b)] as well as in the other condensed matter systems studied thus far [Chatzidimitriou-Dreismann 1997 (a) Chatzidimitriou-Dreis-mann 2000 (b) Chatzidimitriou-Dreismann 2001 Chatzidimitriou-Dreismann 2002 (a) Chatzidimitriou-Dreismann 2003 (a)] are real and are not caused by incorrect data reduction. 

The normalized peak areas in this spectrum are proportional to the neutron cross sections (CS) for 77, D and Nb in a niobium hydride, with composition NbHxDy. The peaks are broadened by the fact that the nuclei have an intrinsic, characteristic spread of momentum Ap when they are hit by the neutron (the original purpose of this method was to deduce the width and shape of the distribution n(p) for 77 or I) in molecules or crystals [Brugger 1984]). 

In the 8-phase of niobium hydride, NbHo.ei, the additional structure observed in both the A and E modes remained in the spectrum of NbHo.03 Do.57 and the coupling model was dismissed [54].An explanation in terms of minor structural differences between the neighbouring sites in this phase was favoured. The degree of detail that can be extracted from more complex materials than the simple metals is limited and the spectra of TbNiAI H, 4 and UNiAl H2.0 are cases in point [55]. 

B. Hauer, R. Hempelmann, T.J. Udovie, J.J. Rush, E. Jansen, W. Kockelmann, W. Schafer D. Richter (1998). Phys. Rev. B, 57, 11115-11124. Neutron scattering studies on the vibrational excitations and the structure of the ordered niobium hydrides the e-phase. 

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