Binary phosphides

Phosphides. Compounds of phosphoms containing the more electropositive elements are generally called phosphides. A large number of binary phosphides as well as many ternary mixed-metal phosphides, metal phosphide nitrides, etc, are known. Some binary phosphides, such as those of nickel, exhibit a variety of stoichiometries (Ni P, Ni P2, Nq2P5, Ni2P, Ni P, NiP, NiP2, NiP ), whereas others, such as aluminum, form only one (AlP). Metalloids such as B and Si also form phosphides. 

As in the parent binary phosphides MV, the metal 2p3 p XPS spectra for the mixed-metal phosphides M XM XV exhibit asymmetric lineshapes originating from final state effects [34] involving the metal-metal bonding network. Virtually no changes in BE are observed relative to the binary phosphides MV or the elemental metals... 

The XPS and XANES investigations of MnP-type binary phosphides MP and mixed-metal phosphides M XM XP discussed above have revealed some of the factors that influence BEs and absorption energies. In particular, a charge redistribution can take place within the metal-metal bonding network when two different... 

Binary munitions, 5 820—821 Binary names, 7 7 394, 395 Binary phosphides, 79 58... 

A number of binary phosphides and polyphosphides (compounds containing P—P bonds), for instance those of Mn, Tc, Re, Fe, Ru, Os can be prepared, often in well crystallized form, by the tin-flux technique. The mixture generally containing an excess of P (red P) and a high excess of tin is heated, possibly at a slow rate, to the required temperature (600°-1000°C) and maintained at that temperature for several days and then slowly cooled. In several cases the products may be recovered by dissolving the tin-rich residue in hydrochloric acid. The preparation of several ternary phosphides and of arsenides and antimonides has also been described (see 6.11.3). 

When lanthanide metals (M = La - Lu) were heated directly with phosphorus, or M203 with PH3 in air, the binary phosphides MP were produced.55 These decomposed in water and, in air at 700°C, were oxidized to phosphates on heating PrP at 2850 °C, a refractory material, deficient in P but containing free Pr and adsorbed oxygen, was formed. EuP2, obtained by reaction of Eu203 with Pn, contains euro-pium(n).56... 

Table 3 Binary phosphides of group 4-all with isolated P atoms...

Table 6 Physical parameters of selected binary phosphides MPj ...

It is important to note that is the maximrun oxidation state in binary phosphides (cf Th3P4, Th2Pn, ThP7) and higher oxidation states are stabilized only by the formation of complexes (see Section 6.2). An exception may be UP2 with the PbCl2-type structure, but the P-P distances (269 pm) indicate an oxidation state (U) < 6. Phosphorus compounds of group 15-17 elements are not covered here PSb, PBi, and PTe do not exist, while other compounds such as PAs (Section 7) are not termed phosphides. 

Other chemical routes to metal phosphides include phosphinolysis reactions and reactions bet3veen metallo-organics and P(SiMe3)3 all involve elimination and condensation processes. Buhro [61] reported the synthesis of several binary phosphide semiconductors along with ternary phases (e.g. ZnGeP2), using solution-phase metallo-organic routes. A recent review of the preparation of II/V materials has appeared [63]. 

Most elements combine with phosphorus to give binary phosphides exceptions include Hg, Pb, Sb, Bi and Te. Types of solid state phosphides are very varied, and simple classification is not possible. Phosphides of the d-block metals tend to be inert, metallic-looking compounds with high melting points and electrical conductivities. Their formulae are often deceptive in terms of the oxidation state of the metal and their structures may contain isolated P centres, P2 groups, or rings, chains or layers of P atoms. 

SCH] Schlesinger, M. E., The thermodynamic properties of phosphorus and solid binary phosphides, Chem. Rev., 102, (2002), 4267-4301. Cited on page 204. 

Binary phosphides with nine-fold coordination of P include FCjP, MUjP, NijP, ZrjP, C02P, RujP, RejP, MUjP, FejP, NijP, TijPj and Nb7P4. Nine-fold coordination of P is found in ternary phosphides such as Fei2Zr2P7 and Co4Hf2P3 which have crystal structures closely related to that of FOjP (Figure 8.3) [12,13]. 

Bulk moduli for ambient conditions (with index o ) are listed in Tables 10.7 for elements, SlO.l for compounds MX, S10.2 for MX2, S10.3 for MX3, S10.4 for binary oxides, S10.5 for binary nitrides, S10.6 for binary borides, S10.7 for binary carbides and silicides, S10.8 for binary phosphides and arsenides, S10.9 for ternary oxides and coordination compounds, SIO.IO for molecular substances and polymers, SlO.l 1 for characteristics of polymorphous modifications of elements and the MX compounds, S10.12 for various phases ofMX2 crystals. 

Table S10.8 Bulk moduli (GPa) and pressure derivatives for binary phosphides and arsenides ...

Jansen and Sperlich (1975) reported about a continuous series of solid solutions between isotypic binary phosphides ScP and GdP, these are the only data known about this system. 

Tris(TMS)phosphine has been used for the preparation of group 13 and 15 (In, Ga, Bi) binary phosphides (GaP, BiP, and InP ) through initial reaction with the corresponding trichlorides followed by vacuum thermolysis (eq 21). The phosphides thus produced are extensively used for material science applications, such as the synthesis of phosphide semiconductors, and this approach to their synthesis is favored due to its easier handling and less elaborate laboratory workup procedures. Notably, the indium phosphide synthesized via this method is free from incorporated iodine. 

Crystal structure of binary phosphides 295 2.3.1. Eu2Pt,AlP3, tl28 344... 

The present chapter consists of two main sections, presenting data about binary and ternary rare-earth phosphides, respectively. Section 1 deals with material on phase diagrams of R-P systems, the crystal structures of all known binary phosphides, their chemical properties, and methods of preparation. Section 2 contains similar information on ternary rare-earth phosphides, and additionally includes systematized data on physical properties and the valence state of lanthanoid atoms. 

Binary phosphides LuP and LuPs are known in the Lu-P system LuPs was obtained by the same method as TbPs. 

Analysis of the minimum interatomic distances in structures of binary phosphides (table 18) does not show any clear tendencies. The 5r p largely depends on the atomic radius of R and to a smaller degree on the phosphide composition. Hovewer, some increase of the minimum interatomic distances 5r p is observed in phosphides with higher phosphorus contents. The minimum value of the (5p p for most phosphides corresponds to the P-P distances in the phosphorus modifications, 0.221 (white phosphorus) and 0.224 (red phosphorus) with an average value of 0.2219 (Hittorf phosphorus)... 

Reliable data about the valence state of ytterbium atoms in their binary phosphides have not been found. 

The structure types of the ternary and quaternary phosphides are presented in order of increasing phosphorus content and at the same P content in order of increasing rare-earth content. Some closely related STs are also discussed. Information about the structure types of ternary phosphides is reported similarly as for binary phosphides above. 

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