Borides reactions with

Unlike bonding, direct boride deposition does not require a reaction with the substrate to form the boride. Both boron and metal atoms are supplied as gaseous compounds. 

Borides are relatively inert, especially to non-oxidizing reagents. They react violently with fluorine, often with incandescence. Reaction with other halogens is not as violent and may require some heat. Resistance to oxidation, acids, and alkalis is summarized in Table 17.5. In oxidation conditions, a layer of boric oxide is formed on the surface which passivates it to some degree. Boric oxide melts at 450°C and vaporizes at 1860°C. It offers good protection up to 1500°C in a static environments but it has low viscosity at these temperatures and tends to flow under stress and the protection it offers is limited.f k l... 

Other ways for preparing BN are the reactions of calcium-boride (CaB6) with additions of boric acid in nitrogen atmosphere at temperatures exceeding 1500 °C [94, 95], or the synthesis from iron boride (FeB) with ammonia at 550 °C and subsequent annealing in ammonia at 1000 °C [96]. 

What is interesting to note here is that the catalyst that facilitates the conversion of the borohydride to borate can be an acid, metal, or metal boride. So, as this reaction proceeds, it is producing the very catalyst that degrades the starting reactant. It is possible to control the boride formation with the use of borohydride esters such as lithium triethoxyborohydride, commonly referred to as superhydride. 

Selenides are also nucleophilic and produce isolable selenonium salts (9) when treated with alkyl halides. They are easily oxidized to selenoxides (10) and further to selenones (11) under more forcing conditions (see Section 4). Reduction of selenides to the corresponding hydrocarbons is most conveniently achieved with nickel boride,or with tri-n-butyl- or triphenyltin hydride under radical conditions. " Other reagents for reductive deselenization include Raney nickel, lithium triethylborohydride, and lithium in ethylamine (Scheme 4). Benzylic selenides undergo radical extrusion reactions under thermal or photolytic conditions to produce... 

Incandescent reaction with boron nitride, hexalithium disihcide + heat, metal borides, metal oxides (e.g., nickel(II) oxide, alkah metal oxides, alkahne earth oxides), nitrogenous bases (e.g., aniline, dimethytiamine, pyridine), galhc acid. 

Catalytic reduction of acetates (tertiary or allylic) with Ni boride (reaction (e)) may serve as a shortcut option to achieve the transition from oxidation level 1 to oxidation level 0. This pathway eliminates the necessity first to prepare sulfur-containing derivatives. 

MURIATIC ACID (7647-01-0) HCl For anhydrous form see hydrogen chloride. Hydrogen chloride gas is quickly absorbed in water, forming hydrochloric acid, a strong acid. Violent reaction with bases, amines, amides, inorganic hydroxides strong oxidizers (with release of chlorine gas), acetic anhydride, borides, calcium carbide carbonates, cesium acetylide cesium cyanotridecahydrodecaborate (2-) 1,1-... 

The product alkyl-2-pyridyl sulfides are of synthetic interest by virtue of their ability to form a chelated lithio anion for reaction with carbon electrophiles. Subsequent removal of the sulfide can then be achieved using either nickel boride or tri- -butyl stannane [4] (Scheme 8). 

A small amount of nickel boride (0.05 equiv) is enough to fulfill the coupling reaction at ambient temperatures with methyl crotonate 31. However, the coupling reaction with methyl acrylate 32 requires larger amounts of nickel boride (0.2 equiv) for better yields, presumably because alkyl iodides cannot compete with acrylates for the small amount of nickel boride catalyst, since the double bond of acrylates is rapidly hydrogenated even at 0°C by this system [16]. 

B.Ganem and J.O.Osby, Synthetically Useful Reactions with Metal Boride and Aluminium Catalysts, Chem Rev., 1986, 86, 763. Organosilicon Chemistry, S.Pawlenko, Walter de Gruyter Berlin and New York. 1986. 

Petit and Pileni [439] reported a relatively recent work on the formation of cobalt boride in which the functionalized surfactant Co(AOT)2 was used in isooctane to form reverse micelles. Sodium borohydride solution was added to it to form the boride particles varying in size from 4 to 7.5 nm. When NaBH4 was used in the aqueous core of a separate reverse microemulsion and similar volumes of the two entities containing Co and B were mixed, the particles that formed had an average size of 10 nm. Similarly, Duxin, Pileni and others [440] synthesized Fe-Cu-B nanoparticles by preparation of Fe(DS)2 and Cu(DS)2 and their reaction with NaBH4. 

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