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Introduction Molybdenum is a chemical element from the group d of transition metals. The free element, which is a silvery metal, has the sixth highest melting point of any element. It readily forms hard, stable carbides and

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72 248 254 Brodrick, S., Giller, K. (1991) Root nodules of phaseolus: Efficient scavengers of molybdenum for N 2 -fixation. J. Exp. Bot. 42

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. Környezetgazdálkodási Intézet. Budapest. 22. Suttle , N. F. : 1983 . Effects of molybdenum concentration in fresh herbage, hay and semi-purified diets on the copper metabolism of sheep . J. Agric. Sci

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Jongruaysup, S., Dell, B., Bell, R. W., O’Hara, G. W., Bradley, J. S. (1997) Effect of molybdenum and inorganic nitrogen on molybdenum redistribution in black gram ( Vigna mungo L. Hepper) with particular reference to seed fill. Ann. Bot. 79 , 67

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Abstract  

Synthesis of monophasic ultrafine molybdenum oxide at low temperatures by thermal decomposition of molybdenum acetylacetonate sol-gel is reported. The sol-gel is obtained through a solvent extraction technique from the organic solvent with the reduction in oxidation state of molybdenum. The thermal behaviour of the sol-gel is studied from the thermal analysis traces. The structural changes accompanying the thermal decomposition of the gel and the formation of monophasic molybdenum oxide is also reported with the help of X-ray diffraction and scanning electron microscopy techniques.

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Journal of Thermal Analysis and Calorimetry
Authors: A. V. Markin, V. A. Ruchenin, N. N. Smirnova, G. V. Markin, S. Yu. Ketkov, V. A. Kuropatov, V. K. Cherkasov, G. A. Abakumov, and G. A. Domrachev

behavior of some bis -(η 6 -arene)chromium and bis -(η 6 -arene)molybdenum fullerides [ 12 , 14 – 21 ], the low-temperature dimerization of anion-radicals of the fullerene at cooling was detected. The data about bonding strength between fullerene

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Journal of Radioanalytical and Nuclear Chemistry
Authors: M. Ganzerli-Valentini, S. Meloni, V. Caramella-Crespi, and P. Borroni

Abstract  

The adsorption of about 50 ions on molybdenum dibromide, (Mo6Br8)Br4·2H2O, in nitric acid was investigated. The preparation of the adsorber and its characterization is presented and discussed. Adsorption mechanism studies were carried out for some noble metals and chromium. Sorption cannot be ascribed to ion exchange mechanism but to formation of insoluble species, and to settlement of few ions into surface sorption sites or into a limited number of cavities in the cluster crystal structure of the adsorber.

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Abstract  

Thermoanalytical techniques, especially temperature-programmed reduction (TPR), were employed for the characterization of oxidic precursors of molybdenum-based catalysts, sulfides derived from them, and three thiomolybdate compounds, employed as models or precursors of hydrodesulfurization atalysts. Correlations were found between TPR data and the presence of single and mixed oxides of Mo and Ni, Co or Fe, as demonstrated by XRD. The same phases and the thiomolybdates were shown to be present in supported catalytic precursors. Differences between the reducibilities of the mixed oxides of Ni-Mo, Co-Mo and Fe-Mo are easily appreciated from TPR, including those of the α- and Β- polymorphic modifications of NiMoO4.

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Abstract  

An isotopic dilution method for the determination of traces of molybdenum has been developed. The method consists of the complexation Mo(V)-SCN with substoichiometric quantities of crystal violet, and its subsequent extraction into chloroform. This procedure was successfully tested for the determination of molybdenum in the range of 0.5 to 20 g.

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Abstract  

A study of fixation of molybdenum on crystalline zirconia was carried out. Molybdenum ions was co-precipitated with zirconium hydroxide at pH-9 and a maximum of ≈39 wt% of molybdenum was found to be incorporated. The mixed material was calcined separately at 800 and 1000°C in a pelletized form and the leachabilities for molybdenum were determined by Soxhlet refluxing at 97°C for 7 days at regular interval, which were found to be negligibile, in the order of 10−3 g m−2 d−1. The analysis of the composite materials by X-ray powder diffraction patterns revealed that molybdenum was fixed in the crystalline lattice of baddeleyite type of mineral of zirconia forming new phases of monoclinic and hexagonal forms of Zr(MoO4)2 which co-existed with a small amount of MoO3 besides baddeleyite.

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