Showing papers on "Molybdenum published in 1975"
TL;DR: THE AUTHORS have reduced ligating molecular nitrogen (dinitrogen) to ammonia in yields of up to 90% at a single metal site and this reaction was performed in a vacuum so that the evolved gases could be analysed and measured.
Abstract: WE have reduced ligating molecular nitrogen (dinitrogen) to ammonia in yields of up to 90% at a single metal site This reaction is important for its possible application to our understanding of the chemical mechanism of the reduction of dinitrogen to ammonia by nitrogenase, where the reduction may occur at a single molybdenum ion site1 Our reaction occurs when compounds of the type [M(N2)2(PR3)4](I; M =Mo or W; R = alkyl or aryl) are treated at room temperature with sulphuric acid in methanol solution: This reaction was performed in a vacuum so that the evolved gases could be analysed and measured On mixing the reagents, one molecule of nitrogen gas was rapidly evolved with a trace of dihydrogen The remaining dinitrogen was spontaneously reduced to ammonia together with some hydrazine, presumably also with concomitant oxidation of the metal M
216 citations
TL;DR: In this article, the authors applied X-Ray photoelectron spectroscopy (XPS) to the study of molybdenum oxides and supported oxide catalysts and showed that the reduction behavior of supported oxide is substantially different from that of unsupported MoO3.
195 citations
TL;DR: In this paper, a monolayer deposition up to about 15-20 wt% MoO3 was demonstrated for a monolingual deposition of alumina-molybdic acid complexes at the surface.
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153 citations
TL;DR: In this paper, the effects of molybdenum in the diet of ruminants in limiting the accumulation of copper in their tissues were reported. But the effect of inorganic sulphate was not investigated.
Abstract: In 1945 we reported (Dick & Bull, 1945) the first observations on the effects of molybdenum in the diet of ruminants in limiting the accumulation of copper in their tissues.Further observations (Dick, 1952) indicated that there was a third factor which materially altered the control by molybdenum of copper accumulation and this factor, present in lucerne hay, was identified as inorganic sulphate (Dick, 1953a). It was also shown that sulphate regulated molybdenum excretion (Dick, 1953b) in the urine and hence the level of molybdenum in circulating blood (Dick, 1953c).
144 citations
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112 citations
TL;DR: In this paper, the mechanical properties of chromium, molybdenum, and tungsten alloys are reviewed with particular emphasis on high-temperature strength and low-tem temperature ductility.
Abstract: The mechanical properties of chromium, molybdenum, and tungsten alloys are reviewed with particular emphasis on high-temperature strength and low-temperature ductility. Precipitate strengthening is highly effective at 0.4 to 0.8 times the melting temperature in these metals, with HfC being most effective in tungsten and molybdenum, and Ta(B,C) most effective in chromium. Low-temperature ductility can be improved by alloying to promote rhenium ductilizing or solution softening. The low-temperature mechanical properties of these alloys appear related to electronic interactions rather than to the usual metallurgical considerations.
112 citations
TL;DR: In this paper, the dissolved molybdenum and vanadium contents of 75 surface and subsurface samples from the northeast Atlantic Ocean have been determined, showing that both elements show very low dispersion about the average values of 10·7 and 1·19 μg 1 −1, respectively.
Patent•
13 Jan 1975TL;DR: In this paper, a part of the content of iron may be substituted with at least one subcomponent selected from the group consisting of nickel, cobalt, molybdenum, zirconium, titanium, manganese, vanadium, niobium, tungsten, tantalum and copper.
Abstract: Iron-chromium series amorphous alloys having excellent mechanical properties, high heat resistance and corrosion resistance consisting essentially of 1-40 atomic % of chromium, 7-35 atomic % of at least one of carbon, boron and phosphorus and the remainder being iron. In said amorphous alloys, a part of the content of iron may be substituted with at least one sub-component selected from the group consisting of nickel, cobalt, molybdenum, zirconium, titanium, manganese, vanadium, niobium, tungsten, tantalum and copper.
BP1
Patent•
16 Jul 1975
TL;DR: In this paper, a process for the oxidation of olefins to unsaturated aldehydes and acids using a catalyst containing iron, bismuth, molybdenum plus at least one of nickel, cobalt, magnesium, zinc, cadmium or calcium is described.
Abstract: The present invention is a process for the oxidation of olefins to unsaturated aldehydes and acids using a catalyst containing iron, bismuth, molybdenum plus at least one of nickel, cobalt, magnesium, zinc, cadmium or calcium and according to the invention, an element selected from germanium, cerium, thorium, manganese, niobium, chromium, praseodymium, yttrium, zirconium, ruthenium, gallium, tin, indium, copper, lanthanum, tantalum or tungsten. These catalysts may also contain certain elements that further enhance the desirability of the oxidation process.
TL;DR: In this article, a preparative method for the synthesis of arenetric-bonyl-molybdenum complexes from tripyridinemolybDENum tricarbonyl and boron trifluoride etherate in the presence of arene was described.
TL;DR: A mechanism of biological nitrogen fixation is formulated which is in accord with the available enzymological evidence and detected as intermediates in the reduction of molecular nitrogen under nonenzymatic conditions.
Abstract: The development of biologically relevant model systems of nitrogenase permitted the simulation of virtually all known reactions of the nitrogen reducing enzymes under nonenzymatic conditions. On the basis of these experiments, a mechanism of biological nitrogen fixation is formulated which is in accord with the available enzymological evidence. The key reactions of the substrates of nitrogenase occur at a molybdenum active site. The non-heme iron, which is bound to sulfur and protein-S⊝ groups, mediates the transport of electrons to the molybdenum active site but does not participate directly in the reduction of the substrates. ATP is required for the acceleration of the reduction and activation of the molybdenum site and is hydrolyzed to ADP and inorganic phosphate. Diimine and hydrazine were detected as intermediates in the reduction of molecular nitrogen under nonenzymatic conditions.
TL;DR: In this article, the hot corrosion behavior of various nickel and cobalt-base alloys has been studied using the coating test, in which alloy samples were coated with approx. 1 mg/cm 2 Na 2 SO 4 and oxidized in slowly flowing oxygen at 1 atm. pressure.
Patent•
23 Dec 1975
TL;DR: In this article, a multi-layer composite metallic sheet having a predetermined coefficient of thermal expansion for use as a heat sink and mounting arrangement when bonded to a ceramic substrate was proposed, where a core layer of a fused metal is sandwiched between two outer layers of the second metal.
Abstract: This relates to a multi-layer composite metallic sheet having a predetermined coefficient of thermal expansion for use as a heat sink and mounting arrangement when bonded to a ceramic substrate. Since copper has a coefficient of thermal expansion greater than that of ceramic and molybdenum has a coefficient of thermal expansion less than that of ceramic, layers of copper and molybdenum can be combined to provide a composite having a coefficient of thermal expansion equal to that of ceramic. To avoid a bimetallic effect, a core layer of a fused metal is sandwiched between two outer layers of the second metal.
Patent•
25 Apr 1975
TL;DR: A metallurgical composition especially suitable for use as a hardfacing to increase the wear resistance of manufactured articles, such as for example tool joints used in earth drilling operations, is described in this paper.
Abstract: A metallurgical composition especially suitable for use as a hardfacing to increase the wear resistance of manufactured articles, such as for example tool joints used in earth drilling operations. This composition has cemented tungsten carbide particles dispersed in a matrix of air hardening alloy steel. Included in the alloy steel are carbon, chromium, molybdenum and vanadium. For weldability, manganese and silicon are added. Also disclosed are suitable ranges of proportions of constituents.
TL;DR: In this paper, the authors verified the presence of oxygen stability range in ternary oxides for molybdenum(IV) perovskites, and the widths of stability range were determined of BaMoO 3, SrMoO 2, and CaMoO 4.
TL;DR: In this article, a number of spectroscopic techniques were used to obtain further information about the scheelite structure of compounds found in the ternary oxide system of bismuth, molybdenum, and iron.