Other Sulphides

Other Sulphides. The phase systems As283-Na28, Ag-Bi-8, ° and Ga-8b-8 have been studied. The thermal dissociation of C82 in C82-Ar gas mixtures has been investigated for gas pressures between 10 and 40 Torr and temperatures up to 2400 The time-resolved emission spectrum of gaseous C82, excited by an N2 laser, and its temperature dependence have been observed. 

Letoffe, J. Thourey, G. Perachon, and J. Bousquet, Bull. Soc. chim. France, 1976, 424. 

The preparation and properties of phosphorus sulphides and selenides have been reviewed, the exact number of compounds being determined from the phase diagram. Phosphorus does not react with tellurium, and the P-S-Se ternary diagram shows no P-S-Se compounds.  

or Fe) have been shown to be isostructural with NiMo3S4, and it has been shown that the same structure is adopted by both Pb,Mo3S4 and Pb Mo3Se4/ The crystal structure of Coo.25TiS2 has been refined.  

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Behret H, Binder H, Sandstede G (1975) Electrocatalytic oxygen reduction with thiospinels and other sulphides of transition metals. Electrochim Acta 20 111-117... 

Copper (II) sulphide is like any other sulphide, ie very reactive vis- -vis oxidants. Therefore detonations occur during mixtures between this compound and magnesium, zinc and cadmium chlorates. 

Good results are obtained for electrodes with sulphides of Pb, Cd and Cu(II), but with certain other sulphides the response time is unsatisfactory. Interference occurs in highly acidic solutions (H2S formation) and in alkaline solutions (at pH > 11) other metal ions sometimes disturb determinations with the metal ISE also, anions may cause difficulties, e.g., in a Cu(H) determination at a Cu(H) ISE if Cu2+ and Cl" are simultaneously present in the... 

Evans CL. 1967. The toxicity of hydrogen sulphide and other sulphides. Q J Exp Physiol 52 231-248. 

In contrast to other sulphide-treatment flowsheets and reagent schemes, which are relatively simple, the flowsheet and reagent schemes for treatment of PGM ores can be highly complex, and varies from one ore type to the next. 

The most preferred sulphidizer used in flotation of oxide copper minerals is Na2S 9H20. Other sulphidizers used in operating plants include NaHS and (NH4)2S. Actually, the selection of a sulphidizer is based on the consumption required for flotation of oxide copper from particular ore types. For example, in some cases the consumption requirement of NaHS is much higher than for Na2S. Figure 19.5 shows the effect of different levels of sulphidizer on the recovery of malachite using xanthate collector. 

Rhenium and non-radiogenic osmium in Australian molybdenites and other sulphide minerals by neutron activation analysis. Journal of the Geological Society of Australia, 15, 189-194. 

The next five chapters deal with deposition of specific groups of semiconductors. In Chapter 4, II-VI Semiconductors, all the sulphides, selenides, and (what little there is on) tellurides of cadmium (most of the chapter), zinc (a substantial part), and mercury (a small part). (Oxides are left to a later chapter.) This chapter is, understandably, a large one, due mainly to the large amount of work carried out on CdS and to a lesser extent on CdSe. Chapter 5, PbS and PbSe, provides a separate forum for PbS and PbSe, which provided much of the focus for CD in earlier years. The remaining sulphides and selenides are covered in Chapter 6, Other Sulphides and Selenides. There are many of these compounds, thus, this is a correspondingly large chapter. Chapter 7, Oxides and Other Semiconductors, is devoted mainly to oxides and some hydroxides, as well as to miscellaneous semiconductors that have only been scantily studied (elemental selenium and silver halides). These previous chapters have been limited to binary semiconductors, made up of two elements (with the exception of elemental Se). Chapter 8, Ternary Semiconductors, extends this list to semiconductors composed of three elements, whether two different metals (most of the studies) or two different chalcogens. 

J. J. Berzelius melted sulphur with an excess of potassium hydroxide and found the product to be a mixture of the monosulphide and thiosulphate. J. Kircher passed hydrogen sulphide over coarsely powdered sodium hydroxide at 100°. M. J. Fordos and A. Gelis made sodium sulphide by heating sodium carbonate with sulphur to 275° the product is obviously a kind of soda-liver of sulphur. J. W. Kynaston melted sodium hydroxide With calcium sulphide and J. V. Esop, and C. Vincent treated a soln. of barium or other sulphide with sodium or potassium... 

Sulphide of hydrogen and/Dark-hrown nearly black pro-other sulphides,. cipitate. 

Another method of producing the same effect— claimed aIbo in the same patent—consists in adding to the gutta-percha and its compounds when passing through the masticating machine, and whether they are mixed or not with orpiment or any other sulphide, about ten por cent, of vegetal wax or tallow. 

If we remember that arsenic meant usually the sulphide, orpiment, and sometimes realgar also, and that by magnesia very frequently was meant native sulphides of lead, zinc and other metals, and marcasite usually meant sulphides of the character of various colored pyrites, the above statement records the production of fusible ferrous sulphide when iron and these sulphides are heated together. The inclusion of lead in the list may also perhaps be explained by an ancient habit of occasionally using the same term for a metal and its principal ores in metallurgy as is sometimes seen in Pliny. Thus galena, the native sulphide of lead, heated with iron would also liquefy it as do the other sulphides. 

The name marcliasita was generally applied to metallic sulphides such as iron and copper pyrites, and other sulphides of metallic luster, though taken by itself the above description gives little basis for such identification. 

The Pyrites Burners.—In the lead chamber process the first chemical action is the oxidation of sulphur to sulphur dioxide by atmospheric oxygen. The iron pyrites (or free sulphur, spent oxide from the gas works, or other sulphides such as zinc blende, as the case may be) is placed on shelves or bars in a series of ovens of suitable type. When iron pyrites or sulphur is used, the combustion when once started proceeds to completion without further assistance by external heat ... 

In addition to the well-known disulphide several other sulphides of carbon have been described,7 although probably they are not in every case separate chemical entities. The existence of the compound C4S, for example, is doubtful. A sulphide of composition C5S2 results,... 

It may also be obtained by fusion of a mixture of arsenic and arsenious sulphide 8 in the calculated proportions. A fiery red product is formed by melting arsenious oxide or arsenic pentoxide with sodium thiosulphate.9 The red sulphide has also been found mixed with other sulphides in the flue dusts obtained during the roasting of arsenical ores.10... 

The solubility-product of copper sulphide, and of the other sulphides which are not soluble in dilute acids, is still less hence hydrogen sulphide precipitates them from... 

The photocatalytic processes that could have been involved in the synthesis of prebiotic molecules are not limited to iron sulphides. Photocatalytic processes occurring on the surface of other sulphide and oxide materials should be considered as well. 

As seen in Table 13.1 and already stated, silver sulphide is added to electrodes based on sulphides of copper, cadmium, or lead to improve conductivity. In fact the functioning is not altered as the solubility product of silver sulphide is significantly lower than that of the other sulphides. The expression for the potential is... 

From the freezing-point curves of nickel sulphides the existence of two other sulphides has been inferred, namely, Ni3S2 and Ni6S5.7... 

The chemical properties are similar to those of the other sulphides of phosphorus, but the compound is less stable, and easily decomposes, giving P4S3 with separation of sulphur. 

Phosphorus Pentasulphide or Diphosphorus Pentasulphide or Phosphorus Tetritadecasulphide, P2S6 or P4S10.—The methods which have been already described in connection with the other sulphides have been successfully used in the preparation of this compound from the theoretical proportions of the elements —... 

None of the effects brought about by these metal sulphides could therefore be taken at face value. However, lead and other sulphides do act as genuine heterogeneous catalysts in the important process of froth flotation by which these minerals are separated from sand and other "gangue materials [120— 122],... 

Silver sulphide, Ag2S.—The sulphide occurs in nature as argentite, and also in combination with many other sulphides. It is formed by direct synthesis from its elements at ordinary temperatures,7 and also by immersion of the metal in solutions of alkali-metal poly sulphides. It can be prepared in cubic crystals by passing sulphur-vapour over heated silver, or by the action of hydrogen trisulphide, H2S3, on silver oxide. It is the only definite compound produced by fusion of mixtures of silver and sulphur in different proportions.9 The black, amorphous form is precipitated by the action of hydrogen sulphide or a soluble sulphide on a solution of a silver salt. It is also produced by the action of hydrogen sulphide on metallic silver, a reversible reaction.10... 

The only important sulphide of molybdenum is the disulphide MoSj, whose properties are described in the next chapter. Apart from the disulphide, three other sulphides have been reported , and some of their salient properties are listed in Table 3.4. 

Similar tests were then carried out with a variety of metal sulphides on six different metal substrates, and the results are shown in Table 6.2. Again they showed that the lives were consistently better with molybdenum substrates, for all the sulphides tested. This strongly suggested that some chemical interaction was taking place, possibly between free sulphur or sulphur compounds and the molybdenum in the substrate. Where the original sulphide under test was itself molybdenum disulphide, this reaction would represent a re-supply mechanism. Where some other sulphide was under test, the reaction would again enable molybdenum disulphide to be formed which would supplement the life of the original sulphide. 

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