Copper atomic hydrogen

Chemicals are classed as either elements or compounds. The former are substances which cannot be split into simpler chemicals, e.g. copper. There are 90 naturally-occuiTing elements and 17 artificially produced. In nature the atoms of some elements can exist on their own, e.g. gold, whilst in others they link with other atoms of the same element to form molecules, e.g. two hydrogen atoms combine to form a molecule of hydrogen. Atoms of different elements can combine in simple numerical proportions 1 1, 1 2, 1 3, etc. to produce compounds, e.g. copper and oxygen combine to produce copper oxide hydrogen and oxygen combine to produce water. Compounds are therefore chemical substances which may be broken down to produce more than one element. Molecules are the smallest unit of a compound. 

But in metals it is relatively common for solid solutions to form. The atoms of one element may enter the crystal of another element if their atoms are of similar size. Gold and copper form such solid solutions. The gold atoms can replace copper atoms in the copper crystal and, in the same way, copper atoms can replace gold atoms in the gold crystal. Such solid solutions are called alloys. Some solid metals dissolve hydrogen or carbon atoms—steel is iron containing a small amount of dissolved carbon. 

On the basis of information on the properties of the nickel-hydrogen and nickel-copper-hydrogen systems available in 1966 studies on the catalytic activity of nickel hydride as compared with nickel itself were undertaken. As test reactions the heterogeneous recombination of atomic hydrogen, the para-ortho conversion of hydrogen, and the hydrogenation of ethylene were chosen. 

Rale Constants of Ethylene Hydrogenation at —Jfl°C on Nickel, and Nickel-Copper Alloy Before and After Their Exposure to Atomic Hydrogen... 

Nickel compounds as catalysts, 191 Nickel-copper alloys, 252, 253 atomic hydrogen recombination, 273-279... 

The hydrogenation of dioxomethylene, step (33) is, most likely, the rate-limiting step, although the hydrogenation of formate in (32) is a also candidate. By assuming that Eqs. (24), (23) and (29) are slow for the water-gas shift reaction and that (33) is slow for methanol synthesis, we arrive at the following set of equations, in which one site is assumed to consist of two copper atoms ... 

The properties of these complexes are well studied 126,132). Although monomeric in solution 126,133), they are dimeric in the solid state and a structural study of Cu(Et2copper atom lies 0.26 A out of the plane formed by four sulfur atoms at a distance of 2.30(1) A. A fifth, long Cu—S bond (2.85 A) is approximately perpendicular to this plane, whereas a hydrogen atom of an ethyl group is situated at the other side of the S4 plane at a distance of 2.86 A from the copper atom. 

Atomic hydrogen is a powerful reducing agent, even at room temperature. For example, it reacts with the oxides and chlorides of many metals, including silver, copper, lead, bismuth, and mercury, to produce the free metals. It reduces some salts, such as nitrates, nitrites, and cyanides of sodium and potassium, to the metallic state. It reacts with a number of elements, both metals and nonmetals, to yield hydrides such as NH3, NaH, KH, and PH3. Sulfur forms a number of hydrides the simplest is H2S. Combining with oxygen, atomic... 

R.L. Sweany, University of New Orleans I was surprised at seeing your report of a 2D Cu atom being able to abstract a hydrogen atom from methane, but, of course, the copper atom is "hot". I wonder if you see methyl take back its hydrogen atom after photolysis or does the radical pair collapse to give HCuCH3 ... 

Copper and nickel are also common contaminants in Si and can often be introduced during annealing treatments. Both of these impurities are extremely rapid diffusers and cannot be retained in electrically active form even by rapid quenching of diffused samples (Weber, 1983). Quite often, complexes involving Cu or Fe impurities are observed by DLTS in heat-treated Si. All of these centers are hole traps, with Cu giving rise to levels at Ev + 0.20 eV, Ev + 0.35 eV and Ev + 0.53 eV, whereas Ni is related to levels at Ev + 0.18 eV, Ev + 0.21 eV and Ev + 0.33 eV. All of these levels are passivated by reaction with atomic hydrogen (Pearton and Tavendale, 1983), and are restored by annealing at 400°C. 

Figure 7. Traces of the a-carbon polypeptide backbone of domains 1 and 6 in the hCP structure. Domain 1 is shown (shaded) on the left hand side of the diagram this domain contributes four histidine residues (not shown) to the trinuclear cluster copper atoms are depicted as black spheres. Domain 6 is on the right hand side of the figure and also contributes four histidine residues to the cluster. The portion of the polypeptide chain colored black is that which is missing in the truncated enzyme. This polypeptide, residues 991 to 1046 inclusive, includes two histidine residues bound to the trinuclear copper center and three residues bound to the mononuclear copper in domain 6 these residues are depicted in black. The absence of the C-terminal polypeptide would also remove over 50% of the interdomain hydrogen-bond and iron-pair interactions observed in the intact enzyme.

In the Cu/Ru system, ruthenium may function as a reservoir for atomic hydrogen, which is accessible via spillover to neighboring copper. Kinetically controlled spillover of hydrogen from ruthenium to copper (5) is consistent with the observed optimum reaction rate at an intermediate copper coverage. 

In those calculations, the contributions from electronic orbital motion (induced by spin-orbit mixing) were estimated from crystal field theory (for the copper atom) or were neglected (for the nitrogen and hydrogen atoms). Here I discuss for the first time direct calculations of these contributions to the copper and nitrogen hyperfine tensors, as well as to the molecular -tensor. 

A sulfuric acid solution of the oxide (25-75% solution) can be reduced with tin, copper, zinc, and other reducing agents forming a blue solution of molybdenum blue which are hydrous oxides of non-stoichiometric compositions (see Molybdenum Blue). Reduction with atomic hydrogen under carefully controlled conditions yields colloidal dispersion of compounds that have probable compositions Mo204(OH)2 and Mo40io(OH)2. Reduction with lithium aluminum hydride yields a red compound of probable composition MosOtIOEOs. Molybdenum(Vl) oxide suspension in water also can be reduced to molybdenum blue by hydriodic acid, hydrazine, sulfur dioxide, and other reductants. 

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