Thiohalides

By contrast to the plethora of simple oxo-halides and thiohalides of P, the corresponding derivatives of P are fugitive species that require matrix isolation techniques for preparation and characterization ClPO, BrPO, FPS and BrPS all form non-linear triatomic molecules, as expected. The corresponding oxosulfide, BrP(0)S, and its thio-analogue, FP(S)S, have also recently been isolated. 

The selenohalides and tellurohalides of both main-group elements and transition metals have been compared with the corresponding thiohalides in two extensive reviews.Other inorganic compounds of Se and Te, with bonds to N, P etc are described on pp. 783-6. 

The thiohalides MoSX are diamagnetic (269). In Mo4S4Br4, molybdenum transfers 12 electrons to the anions, and 12 electrons remain for the cluster M04, forming a doublet for each edge of the M04 tetrahedron (269). The diamagnetism of the compounds of the type MogCligSe can be interpreted in a similar way (273) from structure considerations. These compounds have been found to be dielectric (273). 

Chalcogenide halides of antimony and bismuth have been known since the end of the last century, mainly through contributions by Ouvrard and Schneider. With the exception of BiSeCl, only thiohalides were reported. The early work is summarized in (147) (Sb, before 1948) and (148) (Bi, before 1927), and it will only occasionally be dealt with. Beyond that, these materials had not found much interest. 

Neutral adducts are limited to the oxo porphyrin derivatives (Section 34.3.5.4.i) and to the uncharacterized [NbOCl2(NO)(MeCN)2] obtained by hydrolysis of [NbCU(NO)(MeCN)2].539 This high stability of the MOX3 (X = Cl, Br) adducts toward reduction probably hinders easy access to such M adducts. The reduction of NbSX3 (X = Q, Br), on the contrary, allowed the development of sub-thiohalide coordination chemistry. 

The compounds have been prepared by annealing stoichiometric amounts of the elements or the respective antimony(III) or bismuth(III) sulfide and halides in sealed silica ampuls.11 12 Good crystals are obtained by using a surplus of M2X3.12 The conditions for the preparation of these thiohalides are given in Table VI. 

The reported thiohalides of molybdenum and tungsten are given in Table 4. 

Table 2 Representative List of Oxyhalide and Thiohalide Solvents and Some of Their Physical Properties (interesting as liquid cathodes and solvents for primary Li, Ca and Mg batteries)... 

Theaction of ammonia on phosphorus halides gives either ammoniates or, by elimination of all hydrogen as ammonium chloride, halonitrides. The amides, which should be formed as intermediate products, seem to be difficult to isolate from the true halides, although the oxylialides (p. 109) and thiohalides (p. 118) readily yield such compounds. Exceptionally, phosphorus diamidotrifluoride, PF3(NH2)2, was prepared as a white mass by the following reaction —... 

The effect of volatile phosphorus-containing compounds in polymer flames has not yet been studied. For gas systems it has been found that the flame retarding effect of the additives depends on the concentration (trimethyl phosphate, phosphorus halides and thiohalides). HPO fragments were detected in the radiation spectrum of a H2/O2 flame, upon the introduction of trimethyl phosphate Pj, PO, POj and HPO, P and PH fragments in low concentrations were discovered in a CH /Oj flame inhibited with triphenylphosphine oxide. As regards the flame retardation effect, phosphorus in triphenylphosphine occupies an intermediate position between Sb and As. Triphenyl phosphate is less effective than SbClj. Most effective are POQ3, PCI3 and PBrj. 

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