Bismuth bond type

Sihcon carbide is comparatively stable. The only violent reaction occurs when SiC is heated with a mixture of potassium dichromate and lead chromate. Chemical reactions do, however, take place between sihcon carbide and a variety of compounds at relatively high temperatures. Sodium sihcate attacks SiC above 1300°C, and SiC reacts with calcium and magnesium oxides above 1000°C and with copper oxide at 800°C to form the metal sihcide. Sihcon carbide decomposes in fused alkahes such as potassium chromate or sodium chromate and in fused borax or cryohte, and reacts with carbon dioxide, hydrogen, ak, and steam. Sihcon carbide, resistant to chlorine below 700°C, reacts to form carbon and sihcon tetrachloride at high temperature. SiC dissociates in molten kon and the sihcon reacts with oxides present in the melt, a reaction of use in the metallurgy of kon and steel (qv). The dense, self-bonded type of SiC has good resistance to aluminum up to about 800°C, to bismuth and zinc at 600°C, and to tin up to 400°C a new sihcon nitride-bonded type exhibits improved resistance to cryohte. 

Only a few compounds containing six carbon-antimony or -bismuth bonds are known. The first compound of this type was obtained as colorless crystals by Wittig and Clauss from PhjSb and PhLi (equation 177 ). The ate complex 66 reacts with water forming PhsSb. 

Keywords Aza-Sakurai allylationreaction Bismuth triflate C-C bond formation Mannich-type reaction Mukaiyama aldol reaction /V-AI koxycaihony I am ino sulfones Silyl nucleophiles... 

The 8-N rule states that the number of bonds (or local coordination, x) equals 8 minus the number of the periodic group. This rule is illustrated in Fig. 1.2 where we see that for N — 7 the halogens take dimeric structure types with x = 1, for N = 6 the chalcogenides selenium and tellurium take helical chain structures with x = 2, for N = 5 the pnictides arsenic, antimony, and bismuth take a puckered layer structure with x = 3, and for N = 4 the semiconductors... 

Barbier-type reactions, 9, 433 in catalyzed C-C bond formation, 9, 438 in C-C bond formations, 9, 435 in C-heteroatom bond formations, 9, 440 with copper catalysts, 9, 442 non-catalyzed reactions, 9, 443 miscellaneous reactions, 9, 444 in oxidations, 9, 443 in reduction reactions, 9, 444 Bismuth(V) compounds... 

Similar to the other elements in this group, the exchange reactions studied first and most extensively involve the redistribution of bismuth-carbon bonds with bismuth-halogen bonds. Reactions of the type of Eqs. (159) and (160)... 

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