Silicon boron-halides

Hydroelectric turbines, virtual two-way SMA devices in, 22 349-350 Hydroentanglement, 17 507-508 Hydrofinishing, 15 216 Hydroflumethiazide, molecular formula and structure, 5 162t Hydrofluoric acid (HF), 4 579t. See also Hydrogen fluoride North American capacity of, 14 15t production of, 14 15 silicon solubility in, 22 491-492 in sodium fluoride manufacture, 22 825 solubility of boron halides in, 4 140t solubility of metal fluoroborates in, 4 152t... 

Analysis for boron, halide, free halogen, and silicon is carried out by standard methods following hydrolysis of BX3 (11,79). Specifications for BC13 and BBr3 supplied by Kerr-McGee Corp. are given in Table 2. 

It is easy to reduce anhydrous rare-earth halides to the metal by reaction of more electropositive metals such as calcium, lithium, sodium, potassium, and aluminum. Electrolytic reduction is an alternative in the production of the light lanthanide metals, including didymium, a Nd—Pr mixture. The rare-earth metals have a great affinity for oxygen, sulfur, nitrogen, carbon, silicon, boron, phosphorus, and hydrogen at elevated temperature and remove these elements from most other metals. 

All the hydrides of boron, except B9H15 recently isolated by Schaeffer, were discovered by Stock (1914-20). The starting material was the gaseous product of the reaction between magnesium boride and dilute hydrochloric acid. His remarkable success was due to a vacuum technique which he developed for handling compounds sensitive to oxygen and moisture, such as the hydrides of boron and silicon. Monomeric BH3 was not found because there are insufficient electrons to stabilise the bonding in such a compound, as it is stabilised in the monomeric boron halides. 

The boron halides (not BF3), like the silicon halides, are readily hydrolyzed, whereas the aluminum halides are only partially hydrolyzed in water. 

Boron-containing organosilicon polymers have also been synthesized via a sodium coupling reaction of silicon and boron halides or alkyl boron halides in hydrocarbon solvents [37]. On pyrolysis, mixed ceramics comprising SiC, SiBjt, and Si-(B, C) can be obtained. 

Complex halides of nitrided elements were similarly used to obtain other refractory nitrides such as silicon, boron, and aluminum nitrides. In this case, the following chemical reactions with the stoichiometric component ratio (n = 1) were used ... 

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