Metal Phosphide Sulphides

Metal phosphide sulphides include CuPS, AgPS, NbPS, TaPS and PdPS and another group the semiconductors RhPS, CoPS, IrPS and NiPS. Both these groups form highly symmetrical cubic structures. 

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We have mentioned that connected systems of P atoms occur in some metal phosphides and that there are pairs of directly bonded P atoms in P2H4 and substituted diphosphines, in P2CI4 and P2I4, in certain phosphite ions, and also in molecules such as R2SP-PSR2. The systems P-P and P-P-P form parts of the ring systems in phosphorus sulphides, while the P4 molecule is built of P3 rings. There... 

Test for Non-metallic Elements.—The substance to be analyzed is first decomposed by heating it with metallic sodium, and the resulting mixture, which may contain the following compounds of sodium, is analyzed chloride, bromide, iodide, phosphide, sulphide, cyanide, and sulphocyanide. The decomposition is accomplished as follows A clean, dry 6-inch test-tube is supported near the open end in a vertical position by means of a clamp and iron stand. A piece of sodium equal in size to a cube 3 mm. on each edge is cut and wiped free from oil by means of a filter paper. Any deposit on the sodium should be rejected,... 

When the non-metals are joined to carbon they do not show the reactions with which the student is familiar, on account of the fact that the compounds containing them are, in most cases, not ionized. In detecting these elements it is necessary, therefore, to convert them into compounds in which their presence can be discovered by the usual tests. This can be done by heating the compound to be analyzed with sodium. When decomposition has been effected in this way the non-metallic elements unite with the sodium, and sodium chloride, phosphide, sulphide, etc., are formed. If nitrogen is present it is found as sodium cyanide. The presence of these substances is detected by the methods of inorganic qualitative analysis. 

Phosphines readily form phosphine sulphides, they react vigorously with halogens to form halo-phosphines, and with alkali metals to form metal phosphides. Because of their unshared electron pairs, organophosphines can form a great variety of coordination complexes with metals (Chapter 8). Phosphines are bases their base strengths depend on the degree and nature of substitution to a... 

Thermodynamic Data on Alloys , by Kubaschewski and Catterall, critically surveys data on some 400 binary and ternary metallic systems, with the term alloy interpreted to include transition-metal oxides, sulphides, carbides, nitrides, and phosphides. When available, values are given for the integral enthalpy and entropy of formation of the alloy, the relative partial molar enthalpy and entropy of one component, and the volume change on mixing. 

These are usually reactions of anhydrous transition and B metal halides with dry alkali metal salts such as the sulphides, nitrides, phosphides, arsenides etc. to give exchange of anions. They tend to be very exothermic with higher valence halides and are frequently initiated by mild warming or grinding. Metathesis is... 

The difference in heat of formation is even more marked between the nitrides and phosphides. By the same reasoning as for the oxides and sulphides, the alkali phosphides (where r+ is large) should have higher heats of formation than nitrides while the nitrides, with the exception of Li3N, cannot be prepared, the phosphides and arsenides of the alkali metals are fairly stable compounds. 

The compounds with larger negative ions, like sulphides, selenides and phosphides, in many respect resemble the interstitial compounds. Like the latter, they often show metallic properties and have variable compositions, but their crystal structures are of quite a different type. 

The combination of arsenic with dry nascent hydrogen was observed by Vournazos,14 who obtained a mixture of hydrogen and arsine by heating rapidly to 400° C. in a round-bottomed flask a mixture of three parts of powdered arsenic with eight parts of dry sodium formate. The addition of sodium hydroxide or lime to the mixture prevents the formation of sodium oxalate and hence of carbon monoxide. Arsenious oxide, sodium arsenite or arsenic acid may be used in place of arsenic, but the yields are small. The gas is also formed if arsenic vapour is passed over heated sodium formate. Also, if the sulphide or phosphide of arsenic is heated with the formate, hydrides of both components of the arsenic compound are formed but with metallic arsenides the hydride of the non-volatile component is not formed. 

Carbon unites with molten iron, forming a carbide hence the product of the blast-furnace is not pure iron, but a mixture of iron with its carbide, and also with its sulphide and phosphide, if the ore has contained sulphates or phosphates. When such impure iron is brought in contact with oxygen in a molten or semi-molten condition, the carbon, sulphur, and phosphorus are oxidised mostly before the iron. If lime be present, sulphate and phosphate of calcium are formed. The modern process of removing these impurities is to pour the molten metal into a pear-shaped iron vessel lined with bricks made of magnesia while it is molten, air is blown through the metal, and the carbon burns to carbon dioxide the sulphur and phosphorus are likewise oxidised and combine with lime, a layer of which floats on the surface of the molten metal When these impurities have thus been removed in the Bessemer... 

II-VI and III-V compounds, borides, carbides, nitrides and silicides of transition metals, as well as sulphides, phosphides, aluminides, etc. A1203, AIN, B203, BN, SiC, Si3N4, U02, Y203, Zr02, etc. 

Binary compounds with less electronegative elements include hydrides, nitrides, sulphides and phosphides. They are decomposed by water and can provide convenient routes for the preparation of non-metal hydrides. The anions may be polyatomic or polymerised, as with CaC2, which contains C22- and reacts with water to give acetylene (ethyne) C2H2. 

Electronic conductance is characteristic for the so called conductors of the first class, i. e. for metals (both in solid and fused state) and some metal oxydes, carbides, sulphides, phosphides and borides and it can be explained by assuming the existence of free electrons which act in solid matter as anions. Under the influence of the external electric field these easily movable electrons start an ordered motion while the atoms deprived of their electrons, which are in fact cations, take practically no part in the current conduction and, apart from their vibration within the mean equilibrium positions, remain practically immobile. The passage of the current does not manifest itself by a chemical change of the... 

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