Phosphide density

Titanium Phosphides. The titanium phosphides (154) include Ti P [12037-66-0], Ti P, and TiP (163). Titanium monophosphide [12037-65-9] TiP, can be prepared by beating phosphine with titanium tetrachloride or titanium sponge. Alternatively, titanium metal may be heated with phosphoms ia a sealed tube. The gray metallic TiP is slightly phosphoms-deficient (TiPQ has a density of 408(0) kg/m, and displays considerable... 

At normal current densities, about 96-98% of the cathodic current in a Watts solution is consumed in depositing nickel the remainder gives rise to discharge of hydrogen ions. The boric acid in the solution buffers the loss of acidity arising in this way, and improves the appearance and quality of the deposit. Although phosphides, acetates, citrates and tartrates have been used, boric acid is the usual buffer for nickel solutions. 

In accordance with the electropositive nature of the bridgehead atoms, all di(pyridyl) substituted anions behave like amides with the electron density accumulated at the ring nitrogen atoms rather than carbanions, phosphides or arsenides. The divalent bridging atoms (N, P, As) in the related complexes should in principle be able to coordinate either one or even two further Lewis acidic metals to form heterobimetallic derivatives. According to the mesomeric structures, (Scheme 7), it can act as a 2e- or even a 4e-donor. However, theoretical calculations, supported by experiments, have shown that while in the amides (E = N) the amido nitrogen does function as... 

Iron Phosphide. Commercial iron phosphide anticorrosive pigments usually consist of Fe2P [12751-22-3], Mr 142.7, with traces of FeP and Si02. The pigment is a powder with a metallic gray color and contains 70 % Fe, 24 % P, 2.5 % Si, and 3.0 % Mn. The density is 6.53 g/cm3 and the mean particle size is ca. 3 5 pm. 

The phosphide is a crystalline substance, of metallic appearance, and of density 4-62 at 18° C. 

Sodium phosphides.—By heating in vacuum at 400° to 450° C. the black product formed by the interaction of sodium and phosphorus, a lemon-yellow substance of the formula Na2P5, is obtained.19 It has a density somewhat above 2, is unstable in air, and is decomposed by water with formation of solid phosphorus hydride. 

Potassium phosphides.-—Phosphine reacts with a solution of potassium in liquefied ammonia to form potassium dihydrophosphide, KH2P, white crystals decomposed by moist air with evolution of phosphine.1 On heating, it is converted into tripotassium phosphide, K3P. A solution of potassium in liquefied ammonia reacts with red phosphorus to form potassium pentaphosphide, KPfi.2 The black product formed from potassium and phosphorus loses its excess of metal in vacuum at 400° to 450° C., yielding dipotassium pentaphosphide, K2P5. It is a lemon-yellow substance with a density of about 2, is unstable in air, and is decomposed by water with formation of solid phosphorus hydride.3... 

Rubidium phosphide, Rb2P5.—The phosphide is formed by the interaction of phosphorus and rubidium hydride, and also by Hackspill and Bossuet s method (p. 136). In properties it resembles closely the corresponding potassium derivative, and has a density of 2-5.12... 

Another phosphide, Au3P4, is produced by the interaction of phosphorus vapour and gold.3 It is a grey, brittle substance, of density 6-67, and is formed only in the neighbourhood of 400° C.4 Acids react with it as with an alloy. 

Rhabdite is a crystalline phosphide of iron approximating in composition to (Ni, Fe)3P. It is found in meteorites in the form of minute tetragonal prisms.7 Density 6-3 to 6 8. 

Triferro phosphide, Fe3P, occurs as crystals embedded in a eutectic mixture of this phosphide and iron when phosphorus and iron containing more than 84 4 per cent, of iron are fused together. Its density is 6 74, and melting-point 1110 ° C. It dissolves in concentrated aqueous hydrogen chloride, evolving pure hydrogen. Thus —3... 

Two different types of reactors are used depending on the product synthesized. The first type can maintain pressures up to 150 atm, and is widely used for production of powders in gasless and gas-solid systems. Carbides, borides, silicides, intermetallics, chalcogenides, phosphides, and nitrides are usually produced in this type of reactor. The second type, a high-pressure reactor (up to 2000 atm), is used for the production of nitride-based articles and materials, since higher initial sample densities require elevated reactant gas pressures for full conversion. For example, well-sintered pure BN ceramic with a porosity of about 20-35% was synthesized at 100 to 5000-atm nitrogen pressure (Merzhanov, 1992). Additional examples are discussed in Section III. 

Molybdenum Phosphide, MoP, is formed when molybdenum trioxide is fused -with phosphoric acid and a little chalk, and the grey crystalline metallic mass is extracted first with hydrochloric acid and then with caustic soda. It has density 6-17, and is readily oxidised on heating in air, treating with nitric acid, or fusing with potassium nitrate. 

Tungsten Subphosphide, W4P3.—By strongly heating a mixture of phosphoric acid and tungstic anhydride in a carbon crucible, lustrous steel-coloured crystals of this phosphide are obtained. The crystals are si.x-sided prisms of density 5-21. It conducts electricity well, is very" stable in air even at higher temperatures, and is very resistant to acids. When heated in a current of oxygen it bums brilliantly. It dissolves in a fused mixture of alkali carbonate and nitrate. 

X-ray photoelectron (XPS) studies of nickel boride, nickel phosphide, Raney nickel and Urushibara nickel showed that the electron density on the nickel was a function of the other metal present in these catalysts. 28J29 Boron, aluminum (Raney nickel) and zinc (Urushibara nickel) all increased the electron density on the nickel while phosphorous was an electron acceptor. Comparing the electron densities on the nickel in these catalysts with that on a nickel black prepared by the thermal decomposition of nickel formate (D-Ni) gave the series Ni-B > Ni-Al > Ni-Zn > D-Ni > Ni-P. 

A parameter, Aq, was defined as the relative change in electron density on nickel resulting from electron transfer between nickel and the second element as compared with that on nickel black. Table 12.2 shows the Aq values for these different nickel catalysts. 29 That for the P-1 nickel boride25 is the most negative and that for the NiP-1 nickel phosphide is the most positive. In Fig. 12.5 is shown the relationship between the areal turnover frequencies for the hydrogenation of styrene over these catalysts and their Aq values. 29 These data... 

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