Compounds of Boron

CHR) , formed, e g. from the reaction of diazomethane and alcohols or hydroxylamine derivatives in the presence of boron compounds or with metal compounds. Poly-methylene is formally the same as polyethene and the properties of the various polymers depend upon the degree of polymerization and the stereochemistry. 

Economic Aspects and Uses. The principal producers in the United States are U.S. Borax and Chemical Corp., North American Chemicals Co., and American Borate Corp. Their combined aimual capacity in 1989 was reported to be 735,000 metric tons of equivalent boron oxide [1303-86-2], B2O2 (20). Of this toimage, 50% is exported. About 30% of boron compounds are used in glass fiber insulation. Another 30% is used in other type fibers and borosihcate glasses. Boron is also used in soaps and detergents, fire retardants, and agriculture (see Boron compounds). 

Rate constants have been measured for the reactions of boron compounds with a series of bromomethanes and bromofluoromethanes. Previously it was shown that the reactivity of the chlorine in chlorofluoromethane is substantially reduced by increasing fluorine substitution. The corresponding decrease in the reactivity of bromolluoromethane u as not observed [ifS]. 

The main chemical products produced from these minerals are (a) boron oxides, boric acid and borates, (b) esters of boric acid, (c) refractory boron compounds (borides, eu .), (d) boron halides, (e) boranes and carbaboranes and (f) organoboranes. The main industrial and domestic uses of boron compounds in Europe (USA in parentheses) are ... 

Details of other uses of boron compounds are noted at appropriate places in the text. 

It is thus possible to distinguish five types of boron compound, each having its own chemical systematics which can be rationalized in terms of the type of bonding involved, and each resulting in highly individualistic structures and chemical reactions ... 

G. J. Lf.vinskas in R. M. Adams, Toxicology of Boron Compounds Boron, Melallo-Boron Compounds and... 

Boric acid (H3 BO3) and boron trifiuoride (BF3) exempiity the bonding patterns of boron compounds. As Figure 21-6 shows, both these compounds contain deiocaiized bonds. Each acts as a Lewis acid, readiiy adding an additionai anion to form [B (OH) ] and [BF4 ] adducts. Both adducts are tetrahedrai species in which the bonding can be described using four a bonds formed from sp hybrid orbitais on the boron atom. 

Noth, H., and Wrackmeyer, B. (1978) Nuclear Magnetic Resonance Spectroscopy of Boron Compounds, Springer-Verlag, New York. 

The nomenclature of boron compounds involves some intricacies. IUPAC rules allow the terms borabenzene or borinine for 2 the older name borin has become obsolete with the recent revision of the extended Hantzsch-Widman system (6). Anions 4 are termed boratabenzene ions an alternative would be borininate instead of the earlier borinate (7). 

Garrett, D. E. (1998). Borates. Academic Press, San Diego, CA. An extensive reference book on the recovery and utilization of boron compounds. 

In complete parallel to the discussion in Section 3.5, the conditions for forming a stable 2c->-lc complex or T-bonded compound are intimately related to those for catalyzing the corresponding electrophilic displacement reaction. Thus, the implications of 3c/2e T-bonding go far beyond the chemistry of boron compounds. 

Like iminoboranes, imine-adducts of boron compounds have only recently been prepared and investigated. The adduct obtained from the reaction of diphenylketimine and diborane readily loses hydrogen, even at 20°, to form 1,3,5-diphenylmethylborazine 41) ... 

H. Noth, B. Wrackmeyer, Nuclear Magnetic Resonance Spectroscopy of Boron Compounds, in NMR - Basic Principles and Progress, P. Diehl, E. Fluck, R. Kosfeld, eds., Vol. 14, Springer Verlag, Berlin-Heidelberg-New York, 1978. 

Boron rods provide an alternative wood preservative, which is considered safe for people and the environment. They are made of boron compounds that have been subjected to high temperatures to form water-soluble, glassllke rods. These rods are Inserted Into drilled holes In the wood, strategically positioned where decay is most likely the holes are then plugged to keep the rods In place. When the wood becomes wet, boric acid is released, which prevents fungal decay. Boron pastes have a similar effect. Manufacturers of boron rods are seeking to make these rods available for home use. 

With the development of CO 2 lasers, work on the infrared photochemistry of boron compounds is now appearing in the literature. Future woric on these compounds with UV laser sources is also expected. In this review the effect of radiation on boron compounds in the photon energy range 0.1 eV (CO2 laser) to 10.2 eV (H-a line) is examined. The range of tropics extends from the use of photochemical techniques for synthesis of new compounds to the production and isolation of reactive photochemical intermediates. The photochemistry of borazine is most extensively discussed. 

Interest in the photochemistry of boron compounds dates back as far as 1913 when Alfred Stock investigated the effects of light from a mercury vapor lamp on diboran 6) and on tetraboran 10). In the case of diborane(6) he commented UV light will also decompose B2H6. The volume of a sample in a quartz tube increased by 1/6 after 24 hours exposure to a mercury-arc lamp, and a pale yellow crystalline substance appeared. Stock also observed that B4H q decomposition to B2H is not noticeably influenced by sunlight. 

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