Metal phosphide

Reaction with Phosphorus Nucleophiles. The ethyleneknine ring can be opened using phosphines (91) or alkaU metal phosphides (92) ... 

Phosphorus—Hydrogen Bond. A hydrogen bound to phosphoms has Httie acidic or hydric character. Most of the reactions the bond undergoes are those of a reducing agent. P—H bonds are formed by hydrolysis of active metal phosphides or phosphoms haUdes, by the rearrangement of P—O—H or P—S—H linkages, or by the hydrolysis of P—P bonds (6,17). 

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. 

The alkah metal phosphides of formula M P and the alkaline-earth phosphides of formula M2P2 contain the P anion. Calcium diphosphide [81103-86-8] CaP2, contains P reaction with water Hberates diphosphine and maintains the P—P linkage. 

Metal phosphides can be employed to direct the action of alkyl hahdes more toward primary and secondary phosphines. 

Phosphides are binary compounds containing anionic phosphorus (P ). Heavy metal, alkali, and alkaline earth metal phosphides exist but few of them are commercially important. Phosphides hydrolyze to the flammable and toxic gas phosphine (PH3). The hydrolysis reaction of aluminum phosphide is given below ... 

Hydrolysis of a metal phosphide such as AlP or Ca3P2, the method is useful even... 

The crystallization of glassy Pd-Ni-P and Pd-Cu-P alloys is complicated by the formation of metastable crystalline phaf s [26]. The final (stable) crystallization product consists of a mixture of a (Pd,Ni) or (Pd,Cu) fee solid solution and more than one kind of metal phosphide of low crystallographic symmetry. Donovan et al. [27] used transmission electron microscopy (TEM) and X-ray microanalysis to study the microstructure of slowly cooled crystalline Pd4oNi4oP2o- They identified the compositions of the metal phosphides to be Pd34Ni45P2j and Pdg8Ni[4Pjg. 

White P, either in bulk or in soln, is a good example of the burning type of smoke generator. The resulting colloidal suspension of P pentoxide is quickly hydrolyzed by moisture to become phosphoric acid droplets which are the actual visible constituent of the smoke. Various other burning type smoke generators exist such as those used for signaling purposes and which use red P, metallic phosphides, or P trichloride as the source of the particulate cloud... 

Reactions of alkyl halides with alkaU metal phosphides [39-41], addition reactions of olefins with PHj [42] or the pyrolytic cleavage of P-0 bonds in RPO2H2 [43] are also reported for the preparation of alkyl/aryl functionalized primary... 

Phosphides and amides are closely related, as a synthetic route is based on metathesis of metal amides, especially the respective trimethylsilyl amides, with the appropriate free acidic phosphine or an anion derived therefrom. Reaction of metal halides and trisilylphosphines is an alternative for preparing metal phosphides. 

In this review, we present a selection of studies from our own laboratory, intended to introduce a solid-state chemist to both the practical and theoretical considerations that need to be taken into account in XPS measurements of solids with substantial covalent character. Metal phosphides, arsenides, and antimonides represent such a category of solids where the bonding retains some polarity that notions of electron counting derived from the Zintl concept still prove helpful in providing a frame of reference for comparing charge distributions. We also describe the applications of XAS to complementary studies of the electronic structure of these materials. 

Excellent reviews of X-ray spectroscopic techniques are available in the literature [1,2,5-12], The description below summarizes the major characteristics of XPS and XAS, as applied, when relevant, to the analysis of metal phosphides, arsenides, and antimonides. 

Among binary transition-metal pnictides, only the first-row transition-metal phosphides have been analysed by XPS extensively, whereas arsenides and antimonides have been barely studied [51-61]. Table 2 reveals some general trends in the P 2p3/2 BEs for various first-row transition-metal monophosphides, as well as some metaland phosphorus-rich members forming for a given transition metal. Deviations of as much as a few tenths of an electron volt are seen in the BEs for some compounds measured multiple times by different investigators (e.g., MnP), but these... 

Table 2 P 2p3/2 BEs for various binary first-row transition-metal 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... 

However, with the improved resolution of modem XPS instruments, BE shifts as small as 0.1 eV can be detected and may be significant. These shifts can be interpreted, to a first approximation, by changes in the atomic charge (an intraatomic effect), but to account for more subtle differences, as seen in the mixed-metal phosphides M aM P and mixed arsenide phosphides MAsi -VP>, the role of next-nearest neighbours cannot be neglected. These interatomic effects, as incorporated into the charge potential model, help explain the unusual trends in BE observed in these series. 

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