JOURNAL O F CHEMICAL EDUCATION
RECENT DEVELOPMENTS IN. THE CHEMISTRY OF PHOSPHORUS* L. F. AUDRIETH and 0. F. HILL University of Illinois, Urbana, Illinois
Tm
PAST twenty-five years have witnessed a tremendous increase in the production of phosphorus chemicals of all kmds, both inorganic and organic. While phosphate fertilizers still represent the major tonnage items, it is significant that applications and uses of phosphorus chemicals have increased to such an extent that present production facilities are insufficient to meet the demand. While research has greatly expanded our knowledge concerning phosphorus chemistry, such information has not been generally introduced into elementary and even more advanced texts, with the result that this technically very important and scientifically fascinating field has been sadly neglected. The present discussion will be limited to compounds of pentavalent phosphorus. Five subjects have been chosen for particular emphasis, since these represent either special fields of technological importance or ones in which considerable research activity is now being manifested. It is proposed to discuss in the light of * Presented before the Division of Chemical Education a t the
112th meeting of the American Chemical Society, September, 1947, New Yark City.
modern developments (1) the composition of the strong phosphoric acids; (2) the phosphates and polyphosphates; (3) the glassy polymetaphosphates; (4) the fluophosphates; and (5) the ammonophosphoric acids and related phosphorus-nitrogen compounds such as the inorganic rubber, (PNC18),. COMPOSITION OF THE STRONG PHOSPHORIC ACIDS
It has long been known that the liquid phosphoric acids, ranging in composition between P205.H20 and P20s.3H,O, are mixtures. Reactions involving (a) dehydration of commercial 85 per cent HaPO4by heating, (b) hydration of phosphorus (V) oxide, or ( c ) reaction of the latter with 85 per cent H~POP yield a series of viscous to semisolid products commonly called the "polyphosphoric acids." Such products are best characterized by specifying their PzOs content. New analytical procedures which permit quantitative determination of triphosphoric acid ( I ) , in addition to the ortho-, pyro-, and so-called "hexameta-" acids, have made it possible to investigate more thoroughly these liquid polyphosphoric acids. The pertinent data obtained by Bell (2) are reproduced in Figs. 1and 2. It is interesting to note that ortho- and triphosphoric acids were found to be present over the entire range of compositions from 72 to 89.9 per cent Pdh. Pyrophosphoric acid. is likewise present up to 85 per cent PzOs and the polymer of metaphosphoric acid is present when the P20scontent exceeds 83 per cent. Of real interest is the conclusion reached by Bell that an unidentified phorsphoric acid is present over the P806 range from 78-88 per cent and that this substance is present in maximum amounts when the P20acontent is approximately 83-84 per cent. Bell assumes that it may be a lower polymer of metaphosphoric acid, but proves b e yond a doubt that it is not cyclotrimetaphosphorie acid, since, unlike the latter, it is not converted into the triphosphate when boiled with an excess of sodium hy-
FEBRUARY, 1948
droxide. No cyclotrimetaphosphoric acid appears to be present in these strong phosphoric acids. That the strong acids do, in fact, represent equilibrium mixtures can be demonstrated by adding water to acids of high PzOs content, heating to establish equilibrium, and then determining composition of the resulting product of lower PZOscontent. The compogition will have been found to change to that which characterizes the mixture with lower PzOS content. It is interesting also to note that so-called pure metaphosphoric acid (88.7 per cent PzOs) contains only 80 per cent of the constituent commonly precipitated by barium ions in acid solution (method for determining "hexametaphosphate"). Based on analytical results presented by Bell, "metaphosphoric acid" contains as much as 2 per cent ortho- and 18 per cent triphosphoric . . acids. The question naturally arises: is it possible to prepare any of these polyphosphoric acids in the pure state? Two acids have been prepared as pure crystallme materials-H3P0a (PI) and H&0& 4). The l a b ter is obtained when strong phosphoric acids containing 79-80 per cent P206are allowed to crystallize. It is significant, however, that pure pyrophosphoric acid on melting reverts (2) to the liquid equilibrium mixture characteristic of a polyphosphoric acid with the indicated PzOScontent 179f7 per cent). Dilute aqueous solutions of the various acids have been prepared by treatment of solutions of the sodium salts with an acid exchange resin, (4 6) or by treating the insoluble heavy metal salts with appropriate precipitants such as HC1 and H2S (7, 8, 9). While qualitative tests WY be used to identify the various acids, they can best be distinguhhed by the nature of the pH titration curves. Characteristic inflection points are obtained on titration of each acid with a base corresponding to the existence of definite salts. It is significant, however, that exactly the same amount of base is needed to neutralize the strong acid function of each of the acids as is needed to neutralize the first hydrogen of the orthophosphoric acid resulting therefrom on complete hydrolysis. Regardless of the structure and molecular size of any of the polyphosphoric acids, there is one strong acid hydrogen for each phosphorus atom (10,11). All phosphoric acids, when titrated with base, show an inflection point a t pH 3.84.2, corresponding to neutralization of exactly one hydrogen per phosphorus atom. Additional hydrogen atoms above the H/P ratio of 1 are less easily dissociated and weaker, and show inflection points a t higher pH values. Typical titration curves are given in Fig. 3, reprodnced from data presented by Van Wazer (10). The acids corresponding to the various phosphates were made by passing the salts through an ion exchange column. They were then titrated with tetramethylammonium hydroxide rather than with sodium hydroxide, since the "presence of sodium ions distorts the titration curves due to complex formation." Reference is made to the fact that cyclotrimetaphosphoric acid is a
Figur. 2.
Tha Composition oi Strong Phosphoric Acids (2).
strong tribasic acid, comparable in stength to hydrochloric acid as the steepness of the titration curve reveals. THE CRYSTALLINE POLY- AND MmAPHOSPHATES
Classijkation and Structure. The crystalline phosphates are to be distinguished from those materials commonly designated as the phosphate glasses, such as Graham's salt, which are discussed later. Two classes of crystalline phosphates may be Considered: (a) The linear phosphates and polyphosphates repre(PYrO. sented by the ions: PO^-^ (phosphate), P20,-P phosphake), and p3~,a-~(triphosphate), by the cycle(b) ~h~ cyclic phosphates trimetaphosphate ion, p,og-s. The distimction is based on structural considerations and is dependent upon the accepted factthat the basic ,it in all phosphates is represented by the PO, tetrahe11, lPI), in the phosphorus atom is dron surrounded tetrahedrally by four oxygens, The pyrephosphate ion ,f two tetrahedra with one oxygen to both, while the triphosphate structUre consists of three such tetrahedra linked together: O-
o-4~I
0phosphtte
00I 0-pa-44
A- A-
ppyrophosphrtte
0-
0-
0-
I o--A-o-P-o-J-o-
A A A triphosphate
Claims have been made for the existence of tetraphosphates andhigher linear polyphosphates, but these have not been substantiated either by x-ray diiraction studies (14, 15) of the solid materials containing the proper MzO:PZOs ratios or by chemical examination of the solutions (16). The existence of higher polyphosphates as organic derivatives (esters) is not ruled out nor can it be positively stated that such chains do not exist in solution (see aqueous solutions of the phwphate glasses). It is possible for the PO, tetrahedra to be interlinked to form cyclic structures and a t least one such cyclic compound has been definitely proved to exist both in the solidstate (17) and asan ionin solution (18)-the cyclotrimetaphosphate. It is furthemoreof interest to p04t
82
JOURNAL OF CKEMlCAL EDUCATION
from either the HzPO4- or HPOrions represents examples of anionic aggregation such as are found in chromate, molybdate, tungstate, and vanadate systems except that such anionic aggregation does not occur in aquedus solution, but a t higher temperatures in the solid or molten state.
_/'
TABLE 1 Anionic Aggregation of Phosphates H Cr0,- (in aqueous s o l u t i o n ) ~ C r , O , OH PO; (as T O , - or HQPOIacid a t hlgher temperatures) (A) Or (B) base (A) P0,(POs).(x+3)(Bi . . (PO.i*=. ..-
I
,
.____------
' ! ' ~ " " " " " " "zt ' I
I)
II
10
II
a)
i.Lr.mriw,mmm~ra F ~ w 3. ~ . ~ i t ~ cum ~ t of i ~ pun ~ ~ h o s ~ h s rid. i ~ (10). "I rr W M
out that aluminum meta~hos~hate. , &resented bv the empirical formula Al ( ~ h ) , , - i sactually a cycloietrametaphosphate (19). Soluble salts of a cyclotetrametaphosphoric acid appear to have been prepared and their existence verified by physical measurements (90). It thus seems probable that six- and eight-membered rings containing alternate phosphorus and oxygen atomsform preferentially, although larger rings, such as s, (POJ)~-B,are not ruled out if analogies with silicate systems are permissible (1s).
+
-
A
oyolotrimetaphosphate (P,03 -'
Increase in acidity of aqueous solutions of chromates, molyhdates, and tungstates results in the formation of polyanionic complexes of higher charge. The monoand dihydrogen phosphate ions represent acids which at higher temperatures l o ~ exvater and aggregate to polyphosphate ions. Reaction of these polyphosphate ions with bases in the fused state brings about depolymerization. Such reactions are represented by schematic equations in Table 1. These reactions have been studied most thoroughly as means for preparation of the various sodium salts. The reactions which lead to polyphosphates or cyclic phosphates are presented diagrammatically in Table 2. An excellent review covering the chemistry of the phosphates has recently been published by Quimby (11).
cyclotetrametaphosphete (P40a)
A simple monomolecular metaphosphate ion would seem to be structurally incapable of existence since i t represents a coordinatively unsaturated structure if the tetrahedral model is accepted. Such a fragment, if capable of tansitory existence, could he stabilized (a) by union with a phosphate or pyrophosphate ion to form pyrophosphate and triphosphate, respectively, or (b) by combining with similar fragments to form cyclic structures such as those represented ahove. It is even conceivable that two (POs) fragments might combine to form a diietaphosphate radical representing a four-membered ring, or structurally a case in which two phosphate tetrahedra share an edge in common, that is, share two oxygen atoms. Claims have been made for the existence of such dimetaphosphates (7, $1). Van Wazer (10) eliminates completely any possibiiity for existence of branched structures and, based upon the f a d that all inorganic phosphates contain only one strong hydrogen per phosphorus atom, concludes that "only single linkages exist in aqueous solutions and that the resulting ions must either be straight chains or simple rings." Preparation of the Linear and Cyclic Plwsphates. In effect, preparation of the linear and cyclic phosphates
.
TABLE 2 Preparation of Poly- and Metaphwrphetes
N~H~POI-I + -
(A) .Na2HPO4
(B)
Na~P90, NanH,P20, (NaPOd? (insoluble metaphosphate)
1-
(A)
(B)
I.
475O o,.,
ka,pIoL2(cyclotetrametapho~phatri N~BP,O,O (triphosphate)
Thermal Stability. From the above considerations it is obvious that the constitution and structure of the cyclic phosphates is largely dependent upon their thermal history. Certainly, the trimetaphosphate would appear to be the most stable of the cyclic phosphates, since it can be obtained both from the insoluble met* phosphate, (Maddrell's salt) or from the tetrametaphosphate. All of the metaphosphates will, upon heating to fusion, either be converted to glasses if the melt is cooled rapidly, or into the crystalline polymetaphosphates, preferentially the trimetaphosphate (although not exclusively), if cooled slowly. The triphosphate deserves special mention since it will undergo disproportionation into the pyrophosphate and metaphosphate if heated ahove 600'. Rapid cooling results in the formation of a glass consisting of pyrophosphate in metaphosphate. Slow cooling and
.
FEBRUARY. 1948
annealing a t 550" will cause formation of the triphosphate. It would appear that polyphosphates consisting of m w e than three PO4 tetrahedra cannot be prepared by thermal methods because of their instability, if they exist a t all, a t higher temperatures. Phase relations in the NaPOrNadPzO? system as depicted in Fig. 4 show that Na6P30,0 does not have a melting point but undergoes disproportionation as indicated above (14, 15, 22). Hydrolyszs Reactions. All of the polyphosphates undergo reaction in aqueous solution to yield simpler and more stable aggregates, but only in the case of Graham's salt (hexametaphosphate), cyclotrimetaphosphate, triphosphate, and pyrophosphate have these "reversion" reactions been studied. These particular condensed or "molecularly dehydrated" phosphates are theones whichare best known and ones for which analytical procedures are available. The equations in. Table 3 are those set up by Bell (16) from the results of his latest investigation of this rather controversial subject. Both pyro- and triphosphates hydrolyze more rapidly the lower the pH of the solution and the higher the temperature. The longer the chain length, the less stable do the polyphosphates become toward hydrolysis, that is, the shorter is the useful life of solutions of these products. Of particular interest is the fact that the trimetaphosphate, characterized by a cyclic structure, is much more stable in aqueous solution than the triphosphate. On the other hand, rupture of the ring can be effected immediately by alkali, whereas the stability of the polyphosphate is enhanced by the presence of excess base. .
Hydrolysis Reactions
... ,. Hexametaphosphate: 3(NaPO.)r
N.U.Pn.
+ 12H20
-
2(NaPO& +
(approximating triphosphate). With still higher proportions of NazO mixed products which contain crystalline material in a glassy matrix are obtained. The limit appears to be the pyrophosphate which hasnot yet been produced as a glass (24). Structure. There is no question but that these products are actually glasses, that is, represent "supercooled liquids . . . in which the molecular units (are) constrained in some random arrangement" (11). The process of solution of these glasses in water is most certainly accompanied by some hydration and hyddysis. Physicochemical methods involving diffusion (25) and sedimentation studies of solutions (26,27) as well as endgroup titrations (6,10) indicate that the average molecular (ionic) weight of the particles obtained by solution of such glasses (those of the polymetaphosphate type) range, depending upon experimental procedure, from 4000 to as high as 23,000. Work in our laboratory, in 12 which the end-group titration procedure has been used, reveals variations in molecular (ionic) weight with changes in temperature and time of heating and with the nature of the starting material (28). The titration curves for solutions of.the polymetaphosphate glasses approximate in form that of the trimetaphosphate as the theoretical composition Na-
In 1 % NaOH solvlwn
Trimetaphosphate:
(NaPO& + 2NaOH + NaaPsOlo+ HnO
THE GLASSY METAPHOSPHATES
Preparatzon. Reference has already been made to the fact that fusion of all metaphospbates followed by rapid cooling results in formation of a glassy material, first described by Graham (23) over 100 years ago and now commonly referred to as Graham's salt. Sodium dihydrogqn phosphate is usually employed in the manufacture of Graham's salt-but this product represents only the end member of compositions of varying ratios of Na20:P206which, when heated to fusion and then cooled rapidly, will yield glasses (see Fig. 4). Clear glasses are obtained by rapid quenching of any melt having an N N ~ ~ O : Pratio ~ O ~ between 1 : 1 and 5:3
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JOURNAL OF CHEMICAL EDUCATION
POa,is approached (69.7 per cent PzOs) (84). With increasing NazO content deviations become more marked and an inflection point begins to appear around a pH of 7.5. This suggests that solutions of glasses with lower PzOscontent contain increasing quantities of triand pyrophosphate-which in effect are analytically determinable in such solutions. (See Fig. 5 based on experimental work by Van Wazer.) Bell's (16) work on the hydrolysis of "hexametaphosphate" glasses leads to the very interesting conclusion that the glasses may very well contain cyclotrimetaphosphate units, since both cyclotrimetaphok phate and orthophosphate are the analytically determinable products of this readion, while triphosphate is formed, as might be expected, from the cyclotrimetaphosphate when hydrolysis is carried out in alkaline solution. Solutions of the phosphate glasses, especially those approximating Graham's salt, contain high molecular weight polymetaphosphate particles. The term "bexametaphosphate" is misleading, has no scientific basis or justification, and should be deleted from the chemical literature. THE FLUOPHOSPHATES
Most of our knowledge concerning the fluophosphoric acids and their inorganic salts is the result of researches by Lange (39) and his coworkers. Salts of monofluophospboric acid, HsP03F, of difluophosflhorio acid, HPO2FZ,and of hexafluophosphoric acid, HPFe, have been prepared and characterized. The availability of the first two of these substances as commercial products has been announced recently (SO). Methods for preparation of various derivatives of these acids are given in Table 4. TABLE 4 Preparation of the Fluo~hosphoric Acids and Their De&eti&
+
+
+
3NHB PIOr + NIIlHP08F NH4P09F, NHa (6) P O F H ~ 0 P H P O ~ F * ~ H ~ P O ~ F (c) ( H P O ] ) HF --r HzPOJF H2POaF H 2 0 ( d ) H , P 0 4 HF HF KHPOiF H20 ( e ) KHsPO, (f) Na4P20r HF ( a q . ) 20% N%POaF (g) PC16 6MF --r MPFs 5MCI (where M = N I L f , etc.1 MF (in H F ) + He1 f MPFa ( h ) PCij (a)
+++ += ++ =+ ++ +
Fusion of ammonium fluoride with phosphorus (V) oxide in a 3: 1 mole ratio yields a mixture of the ammonium hydrogen monofluophospbate and ammonium difluophosphate, both of which are extractable by ethyl alcohol, but only the first being precipitable by addition of ammoniacal ethyl alcohol. Other monofluophosphates can be obtained readily by treating aqueous so-
lutions of the ammonium salt with cations whose sulfates are insoluble or sparingly soluble. The silver salt forms very readily and may be used to prepare the alkali monofluophosphatesby metathesis in solution with the corresponding alkali chlorides. Difluophosphates, other than the ammonium salt, may be prepared by treating the nitron salt with the corresponding nitrate, precipitating the nitron nitrate. The nitron salt is obtained by treating a solution of ammonium difluophosphate with a solution of nitron acetate. The fluophosphoric acids are also formed in the hydrolysis of phospho~soxytrifluoride (equation b, Table 4). Recently, Lange and Livingston (31) have reported the preparation of monofluophosphoric acid from metaphosphoric acid and anhydrous hydrogen fluoride. Monofluophosphates may, of course, be prepared from the acid. Lange and Stein (52) have studied the, equilibrium existing in aqueous solutions between phosphates and fluorides. For the reaction represented by the equsr tion (d), Table 4, they observed an equilibrium constant, K, of about 0.9. For a solution of potassium dihydrogen orthophosphate and hydrofluoric acid, the equilibrium constant for the reaction represented by equation ( e ) Table 4, was found to be about 0.7. No rnonofluophosphates were observed to form in a solution containing potassium dihydrogen phosphate and potassium fluoride. On the other hand, tetrasodium pyrophosphate reacted in aqueous solution with strong hydrofluoric acid with about 20% of the pyrophosphate being converted into monofluophosphate. The hexafluopbosphates have been prepared in poor yield by heating phosphorus pentachloride with metal fluorides. Woyski (33) has developed recently a superior procedure whereby hexafluophospha~es are readily prepared in good yields by the reaction of phos~ h o r u s en tach lo ride and metal fluorides usine anhvLous hidrogen fluoride as a solvent medium. The monofluophosphates are similar to sulfates in their solubilities. Lange (29, 84) and Ray (35) have pointed out that such similarity of properties is to be expected due to the electronegativity and size of the ions involved. In Table 5, comparative solubility data of some monofluophosphatesand sulfates are presented. The alkali monofluophosphates are very soluble in water. In neutral or basic solutions, they are fairly stable in the cold toward hydrolysis; they hydrolyze rapidly when heated, or acidified, to form orthophosphates. The difluophosphates resemble the perchlorates in their solubilities. Consideration of electronegativities and sizes of the ions correlates this relationship as i t does that between the monofluophosphates and sul-
-
-
TABLE 5 Solubility of Some Monofluophosphates and Sulfates a t 20'C. (29) Solubility in ""/z Solubility of the sulfate i n -'/r
CaPOsF.SH*O 6.3X10-' 1 . 5 X lo-'
S?PO,F.H,O 5.5X10-= 6 X lo-'
BaPOsF 6X10-' 1x
A@O# 5.93X10-' 2.51 X lo-*
PbP08F 3.2X10-4 1 . 3 x lo-'
Hd'O8F ca.5X10-' 8 X lo-'
85
FEBRUARY, 1948
fates. Difluophosphates undergo hydrolysis to form, first, the monofluophosphates and, then, orthophosphates. PHOSPHORUS-NITROGEN COMPOUNDS
Attention is directed to the phorphorus-nitrogen com~ o u n d swhich , remesent a relativelv unexdored field of chemistry and hold untold possibilfties for research and technical development. The general acceptance of Frank1in's"NitrogenSystem of Compounds" (M),which relates nitrogen compounds to amomnia much as oxygen compounds can be regarded as derivatives of water, has made possible the rationalclassification of these phosphorus-nitrogen compounds and has clarified the relationships which exist among them. The formal analogies depend upon a consideration of ammonia and water as parent solvents with compounds containing the NH2 radical resembling those containing the OH group, and those containing the NH and N groupings corresponding to those containing ionic o r covalent oxygen. These formal analogies are depicted below in which the various "aquo" phosphoric acids are listed as successive dehydration products of a holo-phosphoric acid, P(OH),, whereas the "ammono" phosphoric acids are likewise listed as deammonation products of a hypoP(OH), P(NH.)~ +
PO(OH), -t PO,OH -+ P20, [PN(NH.)~],+ [PN(NH)]. + [P.N~]. phosphophospham phosphorus nitrilamide (") nitride
thetical phospl~oruspentamide (37). The ammono phosphoric acids and the "acid anammonide," P3NSrare all known, but still not too well characterized. Phospham, HNPN, is a highly polymerized substance.
These compounds are most readily obtainable by action of ammonia upon phosphorus (V) chloride,by aprocess of ammonolssis, just as hvdrolvsis . -yields the better known "aquo" acids.. It is &eresting in this connection to point out that from the Franklii point of view magnesium phosphonitrilamide, (MgN)?PN (SS), is the nitroeen analoe of magnesium uhos~hatein the same wav ;hat calcium cyanamide, C~NCN, is the nitrogen analog of calcium carbonate. There are, however, a large number of mixed aquoammono compounds and a few of these are depicted in Table 6. Unfortunately, most of these compounds are much more difficult to prepare than the corresponding N- and O-substituted organic derivatives. Of those listed in the skeletal outline in Table 6, only the mono- and diamidophosphoric acids and the highly polymerized phosphorus oxynitride are known in the free state. Salts of the various'imido-acids and the phosphonitrilic acids have been prepared, Technical interest in phosphorus-nitrogen compounds has been manifested by announcement of the availability of the ammonium salts of imidodiphosphoric acid and dinitridohexaphosphoric acid (39). The phosphonitrilic chlorides, (40) represented by the empirical formula, PNC12, constitute one of the most intriguing groups of substances in the whole realm of chemistry. These substances may he looked upon as the nitrogen analogs of POCll and are obtainable by partial ammonolysis of Pels.
-
+
+
PCh HnO POCh 2HC1 PCls NHo (HC1) ----r PNCll 4HC1
+
+
The phosphonitrilic chlorides represent a series of
TABLE 6 The Mixed Ammono Asuo Derivatives of Phosphoric Acid (41)
O 'H Amidophospharic acid
+
HNIPO(OH)sIz Imidodiphosphoric acid
4
PO(0H).
/
\ OH ~ Diamidophos horic acid
+
2H
Phosphonitr~hcacids (metaphosphimic acids) (where z = 2, 3, 4, 5 6, 7 and 2)
OP
\NH*
.
H~ \POOH
/
Phosphoryl amide imide
+
OPN Phosphoryl nitride
HN
'Po(oH)? Diimidotriphosphorlc acid
+
Trimidotetraphosphoricaoid
\Po(oH~ Pyrophosphorie acid
Phosphoryl trirtmide
P lPN(OH)nl=
Amidopyrophosphoric acid; also dismido- and triamidoderivatives
JOURNAL OF CHEMICAL EDUCATION
compounds, ranging in molecular weight from (PNC& to (PNCI,),. The simplest members, a trimer and a tetramer (in which the tetrahedral configuration of phosphorus is retained), have been shown to be sixand eight-membered rings containing alternate phosphorus and nitrogen atoms. The higher polymers where x = 5 to 11 are presumably represented by linear structures. All of these can be converted by heating to approximately 300' C. into an elastomer, possessing all the properties of rubber. This product is the "inorganic rubber" which has been studied intensively by many investigators. Unfortunately, no way has yet been found to stabilize this product or to decrease its chemical reactivity, since the chlorine atoms are active and will undergo solvolysis. Typical chemical reactions of this analog of POCla are given in Table 7.
(9) ABBOT^, G. A., AND W. C. BRAY,J. Am. C h a . Soc.,. 31,729 . (1909). (10) VANWAZER,J. R., "Titration curves as a key t o molecular structure in polyphasphate solutions." Paper presented a t the 111th meeting of the American Chemical Society, Atlantic City, N. J., April, 1947. (11) QUIMBY,0.T., Chem. Revs., 40, 141 (1947). S. B., J. Wash. Acod.Sn'.,34,241 (1944). (12) HENDRICKS, L., "The Nature of the Chemical Bond," 2nd ed., (13) PAULING, Cornell University Press, Ithaca, N. Y., 1945. K. R., AND K. WUST, Z. anow. Chem., 237, 113 (14) ANDRESS, (1938). E. P., V. HICKS,AND G. W. SMITH,J. Am. Chem. (15) PARTRIDGE, Soc., 63, 454 (1941). (16) BELL,R. N., Ind. En& Chem., 39,136 (1947). AND E. BIANCHI(Univ. (17) CAGLIOTI, V., G. GIACOMELLO, Roma), A t t i accad. Italia Rend., 3 (7) 761 (1942); C. A., 40, 6927, (1946). (18) NYLEN,P., Z. awrg. Chem., 229.30 (1936). Z. Krist., 96,481 (1937). (19) PAUL IN^, L., AND J. SHERMAN, P., Compt. rend., 204, 865 (1937). (20) BONNEMAN, (21) TILDEN,W. A., AND R. E. BARNETT, J. Chem. Soc., 69, 154
TABLE 7 SolGolytic Reactions of Trimeric Phosphonitrilic Chloride KO -[PN(OH)*I., trimerie phosphonitrilic acid NH8 (trimetaphosphimic acid) (PNCI,).-(PH).CI,(NHJ., tri(phosponitri1o) diamidatrtrachlondc I-[PN(NH&],, trimerie phosphonilrilamide
(22) ANDRESS, K. R., AND K. WUST,Z. anorg. Chem., 241, 196 (1939). T., Trans. Roy. Soc. (London), 123,253 (1833). (23) GRAHAM, C., AND C. J. MUNTER,Ind. Eng. Chem., 34, 32 (24) SCHWARTZ, (1942). (25) KARBE,K., AND G. JANDER,KolloicGBeihefte, 54, 1 (1942). (26) LAMM,O., Arkiv Kemi, Mineral. Geol., 17A, No 25 (1944); 18A. No. R 11944). ~, (27) MALGREN. H., A N D 0. LAMM,Z. anorq. Chem., 245. 103 (1940); 252, 256 (1944). L. F., E. L. WEINBERG. AND 0. F. HILL. unpub(28) AUDRIETH, lished observations. (29) LANCE,W., B e . , 62B, 786, 793 (1929). CO.. Tulsa. Oklahoma. Bulletin FPA-I. (30) OZARKCREMICAL May 15, 1944. J. Am. Chem. Soc., 69, (31) LANCE,W., AND R. LIVINGSTON, 1073 (1947). , AND G. STEIN,Ber., &B, 2772 (1931). (32) L A N ~ EW., (33) WOYSKI,N., private communication. To be published in "Inorganic Synthesis," Vol. 111. (34) LANCE,W., Nature, 126, 916 (1930). (35) RAY,P. C., ibid., 126, 310 (1930). E. C., "NitrogeuSystemof Compounds," A. C. S. (36) FRANKLIN, Monograph No. 68, Reinhold Publishing Corp., New York Citv. -~~" , 1935. -~--. (37) AUDRIETH, L. F., R. STEINMAN, AND A..D. F. TOY,C h a . Reus., 32, 99 (1943). (38) MOUREUH., AND G. WETROFF,Compt. rend.. 210, 436 (1940). W. H., (to Victor Chemical Works, Chicago (39) WOODSTOCK, Heights, Illinois), U. S. Patent 2,122,122; C. A., 32,6378' 119381. , (40) AUDRIETR,L. F.. R. STEINMAN, AND A. D. F. TOY,Chem. Reus., 32.109 (1943). (41) AUDRIETH,1,. F., Chemical and Engineering News, 25,2552 (1947).
HY
=(PNY&,
etc.
where Y
=
NzH3,O R , NHR, NR*,
Acknowledgments. The authors desire to acknowledge the help given them in preparation of'this manuscript by Dr. Howard Adler, Dr. W. H. Woodstock, and Dr. R. N. Bell of the Victor Chemical Works, Chicago Heights, Illinois. Appreciation is also expressed to Dr. John R. Van Wazer of the Rumford Chemical Works for use of unpublished information concerning structure and properties of phosphate glasses. LITERATURE CITED (1) BELL,R. N., Anal. Chem., 19, 97 (1947). (2) BELL,R. N., to be published in Ind. Eng. Chem. (3) WERER,A. G., AND G. B. KIN^, "Inorganic Syntheses I," 1939, p. 101. (4) MALOWAN, J. E., to be published in "Inorganic Syntheses," Vol. 111. (5) VANWAZER,J. R., private communication. (6) S A ~ L S O O., N , Svensk Kem. Tid., 56, 343 (1944). (7) TRAVERS, A,, ANDY.K. CHU,Compt. rend., 198,21M) (1934). (8) SAI,IH, R., Bull. me. chim., [31, 3, 1391 (1936).
(1ROfi). ~-.~-,
~
.
