Alkali phosphides

As well as for the preparation of alkali phosphides, the reaction of phosphine with the elements, their oxides or halides, at higher temperatures in quartz tubes have been much used recently for the preparation of other phosphides, in particular those which play important roles in semi-conductor technology. The preparations of the following phosphides using these methods have been described for example, NdP 3s> 36) 3p 137,138) Q p 139.140) SmP, LaP 136,141) TiP, Ti2P (possibly TisP) and InP See also Section IV.9. 

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. 

These workers also obtained hydrogen hemienneaphosphide, P9H2, by the action of heat on the diphosphide. L. Hackspill also reported the solid hydrogen hemi-pentaphosphide, P5H2) to be formed by heating the hemienneaphosphide in vacuo at 80°, or by the action of dil. acetic acid on the corresponding alkali phosphides. 

According to L. Hackspill, when one of the alkali phosphides of the type M2P5 is treated with dil. acetic acid, yellow hydrogen hemipentaphosphide, H2P5, is produced and the same compound is formed when the hemienneaphosphide is heated in vacuo at 80° for several hours The hemipentaphosphide is considered to be of an acid nature, and the phosphides M2P5 to be salts of that acid. 

According to P. Thenard, and L. N. Vauquelin, when heated with potassium or sodium, the phosphates furnish alkali phosphides (q.v.). W. Smith reported that cone or dil- phosphoric acid attacks aluminium with the evolution of hydrogen ... 

Alkali Phosphides.—Soon after the discovery of the alkali metals the direct combinations of these with phosphorus vapour were recorded.1,2 The combination can also be effected under petroleum, the unchanged phosphorus being removed by carbon disulphide.3... 

Methods of Preparation—Alkali Phosphides—Alkaline Earth Phosphides— Copper, Silver and Gold Phosphides—Zino Group Phosphides—Boron and Aluminium Phosphides—Titanium Group Phosphides—Tin and Lead Phosphides—Arsenic, Antimony and Bismuth Phosphides—Chromium, Molybdenum and Tungsten Phosphides—Manganese Phosphides—Iron, Cobalt and Niokel Phosphides—Platinum Phosphides. 

For alkylation of phosphines containing C-H bonds their alkali salts are usually treated with alkyl halides. Thus primary and secondary phosphines can be obtained by metalation of phosphine itself with sodium in liquid ammonia and subsequent alkylation 208 phosphirane, which is unstable, is also prepared in this way, from sodium phosphide and ethylene dichloride.209 High yields of primary phosphines are afforded by alkylating lithium phosphide, which is formed almost quantitatively by metalating phosphine with butyl-lithium.210 Since the hydrogen can be replaced stepwise by metal, unsymmetrical secondary and tertiary phosphines can be built up from PH3 or a primary phosphine.211 Use of alkali phosphides is not limited to alkylation potassium diphenylphosphide reacts quantitatively with iodobenzene, yielding triphenyl-phosphine.212... 

The preparative, value of alkali phosphides for formation of a P-C bond does not rest solely on the high reactivity of the strongly polar P-metal bond — the reactivity increases in the order Li < Na < K. Of equal importance is the fact that, not only the P-H bond, but also P-C, P-P, and P halogen bonds can... 

Aromatic phosphines that are difficult to obtain by other methods can be prepared by heating alkali phosphides with arenesulfonic acid salts, best in ethylene glycol ethers ... 

The bis-hydrazidoyl chloride LXI, on treatment with the alkali phosphides LXII yields the bis-phosphine LXIII ( ). 

Lithium diethylphosphide Reactions with alkali phosphides Hydroxyphosphines from cyclic ethers... 

The alkali phosphide Li3P7 can be obtained in 95% yield by reaction (8.18). The special geometry of the P7 anion makes possible valence bond tautomerism (Chapter 3.2). 

Lithium diethyl phosphide reacts with aluminium trichloride to give the trimer product (9.141). If an excess of alkali phosphide is used, the ethyl analogue of LiAl(PH2)4 (4.149) is obtained (9.142). 

The methylsilyl phosphines are obtainable in reasonable yields by reacting chloromethylsilanes with lithium or other alkali phosphides (9.190-9.192). The tris derivative is also obtained by reaction (9.193). 

P-substituierte Schwermetallphosphide bilden sich in der Regel aus was-serfreien Metallsalzen und Alkaliphosphiden des Typs MePR, MePHR bzw, R(Me)P-[CH2]jj -P(Me)R, Je nach der Natur des Metallsalzes und des Alkali-phosphids wird unter Verwendung beispielsweise von KP(CgHg) bzw. 

A soln. of tri-p-tolylphosphine in dry dioxane vigorously stirred and refluxed 8 hrs. with potassium under argon potassium di-p-tolylphosphide. Y 59.6%. —The alkali phosphides are very reactive and may be used for the prepn. of other organophosphorus compounds. F. e. s. K. Issleib and H. Volker, B. 94, 392 (1961). 

Sulfonimidophosphonates Phosphides s. Alkali phosphides Phosphinaminoboranes 16, 374 Phosphine, reactions with aldehydes, aliphatic 16, 696 —, reductions with — 17, 346 Phosphine boranes... 

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