Sulfides boron

Another boron sulfide, of stoichiometry BS2, can be made by heating B2S3 and sulfur to 300°C under very carefully defined conditions. It is a colourless, moisture-sensitive material with a porphine-like molecular structure, BgSig, as shown in Fig. 6.29b. An alternative route to BgSie involves the reaction of dibromotrithiadiborolane with trithiocarbonic acid in an H2S generator in dilute CS2 solution ... 

The most common organic derivatives of boron-sulfur rings are based on the three ring systems found in the binary boron sulfides, viz. the five-membered rings (RB)2S3 (9.27) and six-membered rings (RBS)3 (9.28) and, less frequently. 

Replacement of the carbonyl oxygen atom by sulfur may be effected by heating with phosphorus pentasulfide (49JCS2142), boron sulfide or silicon disulfide which gives high yields under mild conditions, as, for example, in the synthesis of 7-methoxy-2-methylchromene-4-thione (438) (69JCS(C)2192). Such compounds are more easily converted into their oximes or hydrazones than the oxygen compounds. 

Sulfide Boron sulfide, B2S3, white solid, unpleasant odor, irritating to the eyes, reactive with water to form boric acid and hydrogen sulfide, formed by reaction of boron oxide plus carbon heated in a current of CS2 ai red heat. 

Boron Sulfide. Boron sulfide has essentially covalent bonds. The covalent radius of the boron atom is small so the formation of solid solutions does not appear to be compatible with B2S3. Experimentally we did not observe any solid solution with BeS, ZnS, CdS, and MgS. 

FIGURE 81 The reaction container (10 mm i.d.) and the reaction equations for boron sulfides-assisted synthesis of matel polysulfides and sulfides xB(s) + yS(g) oBjSjtg) bBS2(g) + cS(g) m(metal oxide)(s) + t7B2S3(g) + bBS2(g) + cS(g) p(metal sulfide)(s) -qB203(v). The (s) stood for vitreous state. Reprinted with permission from Wu and Seo (2004). Copyright 2004 American Chemical Society. 

Other reported binary boron sulfides include subvalent B12S, a black crystalline material prepared by a high-temperature reaction of amorphous boron with elemental sulfur, and BS, which has been studied spectroscopically in an electric discharge. A vapor-phase dimer, (BS)2, was identified, and a refractory condensed form of BS was reported from the reaction of elemental boron with sulfur at 1850°C and a pressure of 94 500 atmospheres. Boron disulfide, BS2, has been identified in the gas phase and appears to be the primary compound present in the vapor phase over diboron trisulfrde or elemental boron and sulfur. 

Mononuclear [Mo SP complexes are extremely rare orange-brown (L-N3)MoSCl2, produced upon reaction of (L-N3)MoOCl2 with boron sulfide, remains the only known example (110). The g values for (L-N3)MoSCl2 are all smaller than those for the corresponding [Mo 0] ... 

BiSj(b) Boron sulfide (BS) 255 Lithium borate (Li2Bg0j Q) 303... 

Treatment of the poly(dibenzoylphenylene)s 115 and 116 with boron sulfide gives polymers 117 and 118 with ethene bridges (Scheme 53) [160,161]. These also show blue-green emission (A.max = 478 nm and 484 nm respectively) with some long wavelength emission in the solid state which has been attributed to aggregates. Their EL efficiency is reported to be very low (<0.1%) [162]. 

The retro reaction was accomplished with boron sulfide <77JA5521 > or tetraphosphorus decasulfide <64CB1298>. Several 2-selenones have also been prepared <92ZN(B)898, 94S809>. 

In this class of binary compounds, a new tetragonal form of boron sulfide B2S3 prepared by high-pressure synthesis is noteworthy. Remarkably, instead of a simple structure related to that of normal ambient pressure form of B2 S3, it contains two kinds of supertetrahedra built up from 20 and 34 adamantane-type superclusters to form an elaborate three-dimensional framework (Figure 4) These supertetrahedra are linked to each other in a unique way forming an interpenetrating zinc-blende-type structure. This compound is a wide band-gap semiconductor with an energy gap of 3.7 eV. 

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