Barium oxide, structure

The structure of compounds 45, 47, and 49 was ascertained42 by methylation with methyl iodide in N.N-dimethylformamide in the presence of barium oxide.48 In each experiment, the corresponding l,l-bis(acetamido)-l-deoxy-octa-0-methylaldobiitol was obtained on acid hydrolysis, this afforded two methylated monosaccharides, whose structures confirmed the acyclic formulas proposed. 

Crystal structure of 60 revealed that the complex existed as a dimeric species where the two chromium centers are bridged through the indane oxygen and each chromium metal bears one molecule of water (Figure 17.6). It was therefore proposed, as for the inverse electron-demand hetero Diels-Alder reaction, that the barium oxide desiccant removed one molecule of bound water from the catalyst dimer, which opened one coordination site for binding of the substrate carbonyl.26... 

Preparation, Properties, and Structure of Hydrogen Peroxide. When barium oxide, BaO, is heated to a dull red heat in a stream of air it adds oxygen to form a similar compound, BaO, barium peroxide ... 

A number of tellurium-containing mixed-oxide structures have been described. In all but one, tellurium is in the (+4) state. In barium tellurite monohydrate, [BaTe08,Ha0], the tellurium geometry is three-co-ordinate pyramidal with Te-O distances of 1.847, 1.858, and 1.859 A. These values are smaller than the sum of the covalent radii, and imply considerable multiple bonding. The next closest oxygen atoms are at distances of 3.035 and 3.322 A. 

Metal soaps of barium, cadmium, lead, zinc, and calcium obviously can react with HCl. The addition of a zinc soap (or zinc oxide) to poly(vinyl chloride) gives a material that can be heated at 175°C for 10 or 15 min with scarcely any discoloration, as opposed to a control with no zinc that turns yellow or brown as a result of the conjugated unsaturations and oxidized structures. However, once the zinc is converted in large measure to zinc chloride, there is a very rapid and copious evolution of HCl and the remaining material is blue-black and brittle. The zinc soap, which was a stabilizer, is converted to zinc chloride, a rapid and efficient degradation catalyst. 

Structural binder A wide range of applications in electronics makes use of the plastics as a structural binder to hold active materials. For example, a plastic such as polyvinylidene fluoride is filled with an electroluminescent phosphor to form the dielectric element in electroluminescent lamps. Plastics are loaded with barium titanate and other high dielectric powders to make slugs for high K capacitors. The cores in high frequency transformers are made using iron and iron oxide powders bonded with a plastic and molded to form the magnetic core. 

Among the high-temperature superconductors one finds various cuprates (i.e., ternary oxides of copper and barium) having a layered structure of the perovskite type, as well as more complicated oxides on the basis of copper oxide which also include oxides of yttrium, calcium, strontium, bismuth, thallium, and/or other metals. Today, all these oxide systems are studied closely by a variety of specialists, including physicists, chemists, physical chemists, and theoreticians attempting to elucidate the essence of this phenomenon. Studies of electrochemical aspects contribute markedly to progress in HTSCs. 

The complex formed between 4,6-dinitrobenzofurazan 3-oxide and potassium hydroxide has been evaluated as an explosive [1]. The structure is now7 believed to be that of a Meisenheimer complex [2], The analogous sodium, silver and barium salts are also explosive, the latter being less sensitive to initiation [3],... 

The new silazane 5 may be reacted with activated metals, organometallic compounds or simple metal amides, or may first be transformed to its lithium salt and then reacted with metal(II) chlorides [11]. In all these cases, metal derivatives of 5 are obtained with the general formula j [Mc (/BuO)Si 9N(9M, which have no further base coordinated to the metal. So far we have synthesized amides with M = Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Ba, all elements in oxidation state +2. X-ray structure determinations have been performed on the calcium, manganese, iron, zinc, and barium derivatives. 

The compound Ba5[Ru2(0)n] has been synthesized by solid-state reactions of barium carbonate with ruthenium oxide. The X-ray structure shows that it contains peroxide ions and the ruthenium is in the +5 oxidation state, i.e., Ba5[Ru2(02)0g]. The novel mixed-valence Ru — Ru triple perovskites, Ba3M[Ru2(0)9] (M = Li, Na), have been grown from reactive hydroxide fluxes. ... 

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