Zinc hydride oxide

Zinc hydride [14018-82-7] Z H2 67.40 No toxic effect reported Reacts violently with aqueous acid liberating hydrogen air oxidation slow violent reactions with oxidizers... 

Anodier example of dissociative chemisorption is the heterolytic cleavage of hydrogen on metal oxide surfaces. The reaction of hydrogen wifli a zinc oxide surface produces a zinc-hydride bond and a proton boimd to an oxygen center (Eq. 5-25) [T3 9]. 

The nitrides and ammonia (including the ammonium salts) are the two major types of compounds in which nitrogen has a —3 oxidation state. The nitrides can be divided into ionic, covalent, and interstitial types in the same way as we saw earlier for the hydrides, oxides, and carbides. There are only a few ionic nitrides, the most important being those of lithium, the alkaline-earth metals, and zinc. These are prepared by direct reaction of the elements and readily hydrolyze to ammonia. 

Nickel-iron (conven- tional) Nickel-zinc Zinc/silver oxide (silver-zinc) Cadmium / silver oxide (silver-cadmium) Nickel- hydrogen Nickel- metal hydride Rechargeable primary types, Zn/Mn02 lithium ion systems ... 

Chemical ingenuity in using the properties of the elements and their compounds has allowed analyses to be carried out by processes analogous to the generation of hydrides. Osmium tetroxide is very volatile and can be formed easily by oxidation of osmium compounds. Some metals form volatile acetylacetonates (acac), such as iron, zinc, cobalt, chromium, and manganese (Figure 15.4). Iodides can be oxidized easily to iodine (another volatile element in itself), and carbonates or bicarbonates can be examined as COj after reaction with acid. 

Copper sulfate, in small amounts, activates the zinc dust by forming zinc—copper couples. Arsenic(III) and antimony(TTT) oxides are used to remove cobalt and nickel they activate the zinc and form intermetaUic compounds such as CoAs (49). Antimony is less toxic than arsenic and its hydride, stibine, is less stable than arsine and does not form as readily. Hydrogen, formed in the purification tanks, may give these hydrides and venting and surveillance is mandatory. The reverse antimony procedure gives a good separation of cadmium and cobalt. 

Metal oxides, sulfides, and hydrides form a transition between acid/base and metal catalysts. They catalyze hydrogenation/dehydro-genation as well as many of the reactions catalyzed by acids, such as cracking and isomerization. Their oxidation activity is related to the possibility of two valence states which allow oxygen to be released and reabsorbed alternately. Common examples are oxides of cobalt, iron, zinc, and chromium and hydrides of precious metals that can release hydrogen readily. Sulfide catalysts are more resistant than metals to the formation of coke deposits and to poisoning by sulfur compounds their main application is in hydrodesulfurization. 

A number of basic materials such as hydroxides, hydrides and amides of alkaline and alkaline earth metals and metal oxides such as zinc oxide and antimony oxide are useful catalysts for the reaction. Acid ester-exchange catalysts such as boric acid, p-toluene sulphonic acid and zinc chloride are less... 

In acidic electrolytes only lead, because it forms passive layers on the active surfaces, has proven sufficiently chemically stable to produce durable storage batteries. In contrast, in alkaline medium there are several substances basically suitable as electrode materials nickel hydroxide, silver oxide, and manganese dioxide as positive active materials may be combined with zinc, cadmium, iron, or metal hydrides. In each case potassium hydroxide is the electrolyte, at a concentration — depending on battery systems and application — in the range of 1.15 - 1,45 gem"3. Several elec-... 

Zinc-containing alcohol dehydrogenases take up two electrons and a proton from alcohols in the form of a hydride. The hydride acceptor is usually NAD(P) (the oxidized form of nicotinamide adenine dinucleotide (NADH) or its phosphorylated derivative, NADPH). Several liver alcohol dehydrogenases have been structurally characterized, and Pig. 17.8 shows the environment around the catalytic Zn center and the bound NADH cofactor. 

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