Boron elemental hydrogen

The most widely used method for the synthesis of iminoboranes involves the 1,2-addition of boron-element bonds such as boron-hydrogen, boron-halogen, boron-carbon, or boron-sulfur bonds across the C=N bond of nitriles thereby producing variously substituted iminoboranes (Eq. (2)). The formation of iminoboranes as well as the stability of the products depends on the substituent on the nitrile group, the nature of the boron-element bond to be cleaved during the 1,2-addition across the C N bond, and to a lesser extent on the non-reacting boron substituents 26T... 

Boranes oxidize in air to form boron oxides. Diborane spontaneously ignites in air around 50°C. The presence of impurities can lower the ignition temperature. Tetraborane decomposes slowly at ordinary temperatures but rapidly on heating. Decaborane is very stable at ordinary temperatures. When heated at 300°C, it slowly decomposes to boron and hydrogen. All boranes decompose to their elements at elevated temperatures. 

An interstitial compound consists of a metal or metals and certain metalloid elements, in which the metalloid atoms occupy the interstices between the atoms of the metal lattice. Compounds of this type are, for example. TaC, TiC, ZrC. NbC, and similar compounds of carbon, nitrogen, boron, and hydrogen with metals. 

What is the most common ion or ions for each of these elements sodium, bromine, neon, cadmium, boron, and hydrogen ... 

The interstitial structures comprise the compounds of certain metallic elements, notably the transition metals and those of the lanthanide and actinide series, with the four non-metallic elements hydrogen, boron, carbon and nitrogen. In chapter 8 we discussed the structures of a number of hydrides, borides, carbides and nitrides of the most electropositive metals, and these we found to be typical salt-like compounds with a definite composition and with physical properties entirely different from those of the constituent elements they are generally transparent to light and poor conductors of electricity. The systems now to be considered are strikingly different. They resemble... 

The reactions on the right in Fig. 17.1 give an example common for complex hydrides, where the hydrided material dehydrogenates to form two other product phases X and Y. For example, lithium tetrahydridoborate, LiBHj, dehydrogenates to form the binary hydride of lithium and the elements boron and hydrogen ... 

New principles of propulsion may in time make chemical fuels obsolete. Furthermore, boron is a somewhat rare element. From the point of view of industrial interest in this field, it is fortunate that compounds containing boron and hydrogen have other applications, for example, as reducing agents. 

The Miedema modeP describes bonding in intermetallic, ordered compounds of metallic elements. In addition to the metallic elements the model also includes the elements hydrogen, boron, carbon, nitrogen, silicon, and phosphorus in their metallic... 

Analysis of fullerenes for impurities, especially residual hydrogen has been an important component in the study of the structure and properties of these materials. Revay et al. (2006) determined the amounts of carbon and impurity elements (hydrogen, boron, and nitrogen) in Cgo and C70 fiiUerenes. In a similar vein, recent work by Paul et al. (2009) involved characterization of carbon nanotube materials to determine levels of residual catalyst metals and hydrogen impurities present in commercially available materials. Other recent applications of advanced materials include the study of proton uptake in un-doped and yttrium-doped BaPrOs and compared with that in Gd-doped BaCe03 (Jones et al. 2005). 

It has been shown that the hydrogen desorption reaction is reversible and the end products lithium hydride and boron absorb hydrogen at 690 °C and 200 bar to form LiBH4 [37], Also the reaction of the elemental hydride with diborane forms the tetrahydroboride, and the reaction proceeds via an asymmetric splitting of the diborane due to the overlap of the molecular orbitals of diborane with the orbitals from the H at the surface of the elemental hydride. The diborane splits into an BHLi and a BH3, formed with the hydrogen from the elemental hydride [38]. 

Boron hydride (borane) A neutral compound containing only the elements boron and hydrogen. 

Recall that in contrast to substitutional alloys, where one metal atom substitutes for another in the lattice, interstitial alloys contain atoms of one kind that fit into the holes, or interstitial sites, of the crystal structure of the other. In metals with the interstitial elements hydrogen, boron, nitfogen, or carbon, the aUoy that results retains its metallic properties. 

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