May, 1961
THERMODYXAMIC FUNCTIOSS O F SOMEPHOSPHORUS COMPOUNDS
849
changes on mixing are small and positive, and cor- in the zinc systems, which show the largest excess relate with equally small positive excess entropies. entropies. Although the entropy data for these two systems I n a previous communication we have suggested are uncertain, the entropy-volume ratios probably that the correlations between excess thermody. ~ Thus the volume namic quantities and valence difference which are of the order of 1 ~ a l . / c mdeg. change accounts for most of the excess entropy. characterize the liquid alloys of zinc and cadmium, For zinc-tin and zinc-indium, on the other may be due, a t least in part, to departures from hand, the experimental entropy-volume ratios are “free” electron behavior in these two divalent quite large, about 3.0 and 3.6 cal./cm.3 deg., re- metals.I5 We believe, for example, that the nonspectively. These values should be compared with zero excess entropies a t constant volume may have values of the order of 1.5 cal./cm.3 deg. for the a relation to the details of the electronic structure cadmium systems. We accordingly find that while of zinc and cadmium. Conceivably they may arise in the alloys of cadmium with metals of liigher from a non-linear dependence of the electronic valence the volume changes account for some 70% heat capacity on composition in the various alloy systems. Unfortunately our understanding of of the excess entropies a t constant pressure, the the details of the electronic structure of liquid corresponding percentages in the two zinc systems metals is still rather unsatisfactory. Therefore, are less than 50%. I n both types of system there more firmly founded conclusions regarding these are significant entropy contributions which cannot problems must await further investigations. be attributed to the volume change. Clearly ( 1 5 ) 0. J. Kleppa and C. E. Thalmayer, J . Phbs. Chem., 6 3 , 19.53 these contributions are particularly important (1959).
THERMODYNAMIC FUNCTIONS OF SOME PHOSPHORUS COMPOUNDS BY ROBERT L. POTTER AND VIXCEXTS. DISTEFANO American Cyanamid Company, Stamford, Connecticut Received December IO. 1360
The thermodynamic functions of P(g), Pz(g), PN(g), PO(g), PC(g), PFa(g), PH3(g) and Pd(g) have been computed from spectroscopic data according to statistical mechanical formulas. Heats of formation of these compounds have also been selected so that the complete thermodynamic properties of these compounds are available.
Introduction The high temperature thermodynamic properties of phosphorus compounds are a necessary prerequisite for any study of high temperature equilibrium involving phosphorus as a component. Tables of thermodynamic functions for some of the compounds reported here have been published but not with the accuracy or internal consistency strived for herein over the temperature range of 273.15 to 5000°K. Because many of the compounds have important excited electronic states, and a t the same time significantly low dissociation energies, it is difficult to interpolate on thefunctions. Therefore they have been reported a t even 100’ intervals. Ik-~ctiousfor P(g), (g = glib) have been given hy Stevenson and Yoqtl and appear also in a summary by IJarr.2 Thew n ere computed with I.C.T. constants and extend only to 1500°K. Gordon3 also has calculated functions for P(g) but the internal energy levels were lumped togdher i n nn effort, to simplify the calculations. Functions for P2(g) also hare been reported by (;ordon?; however the fundamental constants have changed since his work. Functions for P,l;(g) also have been given by G ~ r d o n and , ~ a few a t widely spaced intervals by McCallum and Leifer. * P. Stevenson a n d D. A l . Yost, J . C h e m . Phys., 9, 403 (1941). (2) T. D. F a n , “Phosphorus. Properties of t h e Elements and Someof I t s Compoiinds ” Tenn. Valley Auth., Wilson D a m , Ala., 1950, Chem. Enp. Report No 8 (U 9. Govt Printing Office, Washington 25. D. C,), (3) J . S. Gordon, WADC, Technical Rept. No. 57/33 (1957). (4) K. J. RlcCalluin a n d E. Leifer, J . Chem. Phys., 8 , 505 (1940). ( 1 ) D.
For PO(g) tables have been published by Gordon3 but without inclusion of all the excited states, and the same is true of PC(g). For PH3(g), PF3(g) and P,(g) functions have been reported up to 1500’K. by Stevenson and Yost,l Farr2 and more recently on PH3 by Sundaram, Suszek and Cleveland,6 and on PF3by Wilson and Po10.~ The spectral data for these compounds have been selected carefully and with the latest values of the fundamental constants, thermodynamic functions have been calculated to 500O’K.
Calculations The fundamental constants were taken from Wichers,’ and Dumond and Cohen.s The entropy constant was taken as -2.31540 which compares with -2.31533 used by Pottersg The translational contributions for P(g) were calciilated according to the standard formulas, while the contributions due to the internal levels were evaluated hy directly summing over the first eight internal energy levels. The energy levels and niultiplicities for P(g) were taken from For PZ(g), the translational contributions w\-erc (6) S. Sundarani, F. Suszek a n d F. F. Cleveland, ibid., 32, 251 (19h0). (6) RI. IC. Wilson and S. R . Polo, %bad.,20, 1718 (1952). (7) E. Wichers. J . A m . Chern. Soc.. 80, 4129 (1958). (8) J. W. M. Dumond a n d E. R. Cohen, “Handbook of Physics.” Chapter 10 E. U Condon and H. 0. Odishaw, Editors, MeGraw-Hill Book Co., Inc., New York, N. Y., 1958. (9) R . L. Potter, J . C h e m . P h y s , 31, 1100 (1959). (10) C. E. Moore, “Atomic Energy Levels, I, 11, 111.” Natl. Bur. Standards Circ. 647, U. S. Govt. Printing Office, Washington 25, D. C.
evaluated according to the same relatioiis as for l'(g). The internal partition function was approximated as an aiiharmonic oscillator, and a rigid rotator plus cent'rifugal stretching aiid vibratioiirotation interactions. Rotatioii-vibration cut-off was included in evaluating the partition fuiict,ion as done previously by P ~ t , t e r .The ~ spectroscopic data are summarized by Douglas and Rae.",'? The ground state is I&+ and t'he first excit'ed st'ate is 17rg at 81.-134 c m - I above v" = 0 of the ground state. Tho dissociation energy of P2(g) is 10,598 cm. --I obtained by predis~ociat~ion.13X level, B1zli,+, at 46i80 ( m - l \vas ignored because it contributes a iiegligible amount to t'he internal partition fuiictioii. Our calculatioiis agree reasonably well with those of Gordon3 except' at high temperatures where the effect of rot'atioii-vibratioii cut-off is noticwble. The molecule 1'S(g) was treated much the same way as I>&) exvept that the first excited level at about' 40,000 cm. ~ - 1n-as ignored because ita contribution to the intcm:tl partition function is negligible. The spectrosropir data required were The equilibrium for taken from Herzberg. t'he formatioii of 1's from l', and Sshas heen inh recal(dat~ioii vest,igated by Huffmaii, t.f of their results gives ahout 58,000 cm-I as the dissociation energy for I'S(g). This is above the value quoted hy Hufj'man15hiit below that estimated by Gaydon. lei Thir dissockt ion energy fixes the rotation-~-ibratioii cut-off. Our wlculat'ions are comparable with those of Gordon except' a t high temperatures where the rotl\tioii-~,ibrat,ioii cut-off beconies noticeable. It may he noted an incorrect sign occurs in S.B.8. C k u l a r 300" iii t,he heat of formation of PSigj. The molecule PO(g) has the most complivated spectrum of any of th(i diatomic molecwles discussed here.18 The grouncl state is a ? H state with a spin splitting of 224 The next state lies 30,696 c m - l above t8hi,;aiid is either a 2Z or a ZH state. The next, state is designated h28+ a i d it lies a t 40,487 c ~ n - 'aboi-e the ground state. 14iere a r e at least four states further up that ha\-e heen ohsenTed. although for some only oiie vibrational state h:ts been rec~rded.'~Singh?O has analyzed the transit'ions X'a+R aiid has c ~ i i cluded that B is ?Z+. Taking into account all the predissociatioiis observed, the iion-crossing rule, correlation rules, etc. it, appears that this designation by Singh is the correct one aiid that Dressler's earlier assignment, of 13 ai; z~ is incorrect. (11) A . E. Donglas and R. S.Rao, Can. J . P h y s . , 36, 5ti.i (1958). (12) 11. Ashley, F'hys. Keu., 44, 919 (1933); A . E. Doiiglas, Can. J . P h y s . , 33, 801 (1955): K. Dressier. Helo. Ph!/s. A c t a , 28, 563 ( l Q . j . 5 ) ; E. .J. l l a r a e s . I'hus. Rw., 70, 499 (1940). (13) G. Herxberg, Ann. P h y s i k . 15, 077 (1932). (14) 0.Heraberp. "IXatoInio Molecules," I). Van Nostrand Co., New Tork, S. I-., l9ti0, 2nd Ed. (1,j) E. 0. IIirffman. G , Tarhiitton, K. I-.I3linorr. \V. E. Cat[., \V. Iedthe spectroscopic data dist'ance is 2.21 obtained by electron diffrac- used in the calculations for diat'omic molecules, tion.*& The vibrat'ional spectrum of P4 has been while in Table I1 are collected the data for the examined both in the infrared and by Raman shift's. polyat'omic molecules. The thermodynamic funcThe infrared data come from Bernstein and Powl- t'ions are exhibited in Tables 111-X, while Table ing26and the Raman data from J'enkateswaran. 2' XI records t'he standard heat of formation a t 0 Our results compare reasonably well wit'h those and also a t 298.15'B. for convenience. These report'ed a t the low temperatures by Stevenson calculat'ions of t'hermodynamic functions are for and Yost,,l E7arr,2 Suiidarani, Suszek and Cleve- the ideal gases, without nuclear spin effects, at land,j and Wilson and Polo.'j There is consider- one atmosphere pressure. These ivere computed able variance when compared to Gordon's3 results. on an IBiLl704 digital computer. These thermodynamic funct'ions require for their use the heat of formation with respect' to TABLE 11 some standard, at' the absolute zero. Crystalline, MOLECCLAR DATAFOR POLYATOMIC JIOLECCLES \vhite, /3-phosphorus has been chosen as the standXonients of inertia X 104". g, ard state of phosphorus.28 The heat of vaporiI1 I2 1% zat'ion of a white phosphorus from Daintoii and = 892 an.-' -Hoe for white phosphorus, PF, vl(AI) Kimberlyz9 nnd HoZys v2(A2)= 187 cm.-' allowing for the CY+@ transit'ion leads to AHoo = YQ(E) = 860 CIII.-' 15,760 cal.,'mole for P,(g). From analyses of high u,(E) = 344 cm.-l 174.445 104 297 104.297 temperature equilibrium data on mixtures of P,PH, vi(&) = 2328.9 c m l (g) aiid P&), Stevenson and Yost' and also ~:(.4?) = 990 cm.? Farr2concluded that Clll.?
Pdg) = 3Pdg)
AHoO = 53,620 tal.
vI(E) = 2328cm.-' Q(E) = 1121 cm.-l
7.1745
(i.251
(i.2'il
aiid the thermodynamic functions reported here VI(&) = 606 cm.-l are in agreement, wit,h this. Since the dissociation Pd v2(E) = 363 e m - ' energy of P,(g) has been given as the result of va(F?) = 461 c m - ' 251.17 251.17 251.17 predissociation, it is then possible t o obtain t,he heat of formation of' P(g) with respect to the same TABLE IIr standard state, and hence of all the diatomic niole- THERMODYNAMIC FENCTIOSS O F P(g) IS IDK.\L Gas STATE cules for which dissociation energies are available. For PHS(g), the heat of formation a t 298.15OK. P, CKO. cal. deg. cal. der. cal. deg. I has been taken from S.B.S.Circular dO0,17 while 2'. mole mole 1nolc
(V), -1
-1
OK.
11. E. Stroup a n d R.A . Oetjen, J . Chem. P h y s . , 21, 2092 (1953); ,J. B. Ham-ard, ibid., 3 , 207 (1933); L. TV. Fung and E. F. Barker, P h y s . E a , 45, 238 (1934); 31. H. Severtz and R. E. T e s t o n , Jr., J . Chem. P h g s . , 21, 898 119.533: C. C. Lames and JI. \T. Strandberr, Phbs. Re r.. 81, 798 (1951); J . AI. Delfosse, BUZZ. S c i . h a d . Rug. B d g . , 20, 1157 11934); A I . de Heniptinne and .J. %I. Delfosse, i b i d . , 21, 19 (1935); If. Subert, %. a n o r g . allgem. C h e m . , 274, 24 (1953). ( 2 5 ) L. R. Maxwell, S. B. Ilendricks a n d V. 11. Xosley, J . Chem. Phys., 3, 699 (1935). ( 2 6 ) A . J . Berristein a n d J. Powling. J . Chem. Phgs., 18, 1018 (1950). (27) C. S. Venkateswaran. Proc. Ind. h a d . Sei., ZA, 260 (1935); 4 8 , 343 (1936). (28) C. C . Stephenson, R. L. Potter, T. G. XIaplr and .I. C. Morrei\-, 130th Meeting Am. Chem. Soc., Sept., 1956. 1293 F. S. n a i n t o n and H . &I. Kimberly, T r a n s . F a r a d a y Soc., 46, $112 (19.50).
273.15 298.15 300 400
,500 fiO0 TOO 800 900 1000 1100 1200
33.576 34.011 34.041 35,471 Sti 570 :37 485 38,251 38.914 39 . 499 40.033 10.196 40,928
(30) E. Neale a n d L. T.
-1
-1
-1
38.544 33.$177 39.009
4.968 1 968
-10.4:39
4 , OB8
41.547 13 . 4x3 4 3 , 219 43.882 44,407 44.991
4.9G8
45.464
4.!)68 4 . R(i9
45,897
n.Williams, J . Chem. ,SUI..,
4.S(i8 4 . 008
-1.968 4 .!)(if3 4.968 4.968
248: f l D i i i .
ROBERT L. YOTTXH.ASD TISCEST N. DISTEFASO
832
TABLE I11 (Continued) 1300 1400 1500 1600 1700 1800 1900 2000
41.326 41.694 42.037 42.358 42.659 42.943 43.212 43.468
46.294 46.663 47.006 47.328 47. 630 47.916 48.188 48.447
4.971 4.974 4.979 4.987 4.990 5.015 5.035 5.062
2100 2200 2300 2400 2500 2600 2700 2800 2900 3000
43.711 43,943 44.165 44,377 44.582 44.779 44,969 45.152 45.330 45.502
48.695 48.933 49.162 49.383 49.597 49.805 50.008 50.206 50.399 50.588
5.094 5.132 5.175 5.224 5.279 5.339 5,403 5.471 5.542 5.617
3100 3200 3300 3400 3500 3600 3700 3800 3900 4000
45,660 45.832 4.5,990 46.143 46.294 46.440 46,583 46.723 46.860 46.995
50.774 50.956 51.134 51.310 51.483 51.654 51.822 51.987 52.150 52.311
5.693 5.771 5.851 5.931 6.010 6.090 6.168 6.245 6.320 6.393
4100 4200 4300 4400 4500 4600 4700 4800 4900 5000
47.126 47,255 47.382 47.506 47 , G29 47.749 47.867 47.983 48.098 48.211
52.470 52.627 52.781 52.933 53.084 53.232 53.378 53.522 53,665 53.805
6 464
6 532 6.597 6.659 6.717 6 . 773 6.825 6.873 6.918 6.960
TABLE IV THERMODYXAMIC FUNCTIOXS OF P2(g)IN IDEAL GAS STATE T,OK.
273 15 298 15 300 400 SO0 A00 TOO
800
nno IO00
cal. des. -1 mole - 1
44,346 44.970 45.011 4 7 , O!JR 18.740 3 0 , 12fi 51 .31.i 52.361 53,295 5'4.140
ioon
54,911 L5.621 5 6 . 278 56.891 57.464 58.003 58.511 58.993 69.450
"0OU
59 88.1
1100
1200
1 :m
1400 1500 1600 1TOO 1800
SO, cal. deg. -1 mole-'
CUD, oal. deg. -1 mole-'
51,442 52.108 52.155 54.41fi 56.242 59,0141 60 24ti 61.273 62 198
7,540 7.650 7 ,664 8.049 8.310 8.48.5 8 . 604 8.690 8.752 8.800
63.038 ti3 ,809 64.519 65.179 65.795 66.372 66.915 67.427 67.913 68.374
8.838 8.868 8.893 8.914 8.932 8.948 8.962 8.974 8.986 8.996
--
d l
r-. . I
/!$
2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 3100 3200 3300 3400 3500 3600 3700 3800 3900 4000 4100 4200 4300 4400 4500 4600 4700 4800 4900 5000
T'ol. 65
60.299 60.696 61.076 61.440 61.791 62.128 62.454 62.768 63. O i l 63.365 63,650 63.926 64,193 64.454 64.707 64.953 65.192 65.426 65.654 65.876 66.093 66.305 66.512 66.714 66.912 67.106 67.296 67.482 67.665 67.844
68.813 69.232 69.633 70.018 70.386 70.741 71.083 71.412 71.730 72.038 72.335 72.624 72.903 73. 175 73.439 73.695 73.945 74.188 74.425 74.656 74.882 75.102 75.317 75.527 75.733 75.934 76.131 76.324 76.513 76.698
9.006 9.015 9.024 9.032 9.040 9.047 9.054 9.061 9,068 9.074 9.080 9 ,086 9.092 9.098 9,104 9.110 9.115 9.121 9.126 9.131 9.136 9.140 9.145 9.139 9.158 9,157 9.160 9.164 9.166 9.168
TABLE V THERMODYNAMIC FUNCTIONS O F PN(g) I N IDEAL GASSTATE
("e+!?!)
T,OK. 2i3.15 298.15 300 400 500 GOO 700 800 900 1000 1100 1200 1300 J 400 1500 1600 1700 1800 I ROO "00 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000
I
SO,
cal. deg.-l mole -1
oal. deg. - 1
42.851 43.461 43.504 45,519 4'1 ,099 48.408 49.531 50.519 51.401 52,201 52.932 52.606 54. L'32 51.816 55.364 55.880 56.367 56.830 3i ,269 57.(i88 58.088 58.471 58.838 59.191 513.531 59.858 60.174
49.818 50.437 50.481 52,557 54.228 55.643 56,874 57.965 58.944 59.832 60.644 61.392 62.084 6 2 ,72!j 63,332 63.898 64.432 64.937
60.479 fi0.774 ti1 ,060
68.880
mole -1
CI>O, cal. deg. -1 mole - 1
7,050 7.096 7.100 7.3A5 7.636 7.883 8.088
8.248 8.375 8.47t' 8.557 8.6%:$ 8.677 8.722 8.761 8 .793 8.821 8.846
65.41ti
8.868
65.871 66.306 06.720 67.117 ti7.498 67.863 68.215 68.553
8.887
fig. 190 I;cJ.501
8.905 8 . R20
8.935 8.948 8.960 8.971 8.982 8.992 9.001 Y.010
May, 1961 SI00 3200 3300 3400 3500 3600 3700 3800 3900 4000 4100 4.200 4300 4400 4500 4600 4700 4800 4900 5000
G1.337 61.606 61.867 62.121 62.368 62.608 62.842 63.071 63.293 63.511 63.723 63.931 64.134 64.332 64.526 64.716 64.903 65.085 65.264 65.440
69.797 70.083
70.361 70.631 70.893 71.148 71.396 71.638 71.874 72.104 72.328 72.547 72.761 72. 970 73.175 73.375 73.571 73.763 73.951 74.136
TABLEVI THERMODYNAMIC FUNCTIONS OF PO(g) T,O K . 273.15 298.15 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 3100 3200 3300 3400 3500 3600 3700 3800 3900 4000
833
T H E R M O D Y N A M I C h Y C T I O S S OF sOM€i: P H O S P H O R U S C O M P O c s n s
IN
9.018 9.026 9.034 9.041 9.048 9.055 9.062 9.068 9.074 9.080 9.086 9.092 9,098 9.103 9.108 9.114 9.119 9.124 9.129 9.134
IDEAL GASSTATE
SQ
CPD,
cal. deg.-l mole-'
cal. d;?g.-1 mole -1
cal. deg. -1 mole -1
45.030 45.690 45.736 47.907 49.599 50.993 52.184 53.225 54.151 54.988 55.750 56.451 57.100 57.705 58 271 58.803 59 304 59.780 60 231 00.660
52.557 53.221 53.268 55.467 57.214 58.678 59.943 61.058 62.056 62.957 63.780 64.536 65.235 65.886 66.493 67.064 67.601 68.109 68.591 69.048 69.485 69,901 70.300 70.682 71.049 71.402 71.742 72.070 72.387 72.693 72.989 73.277 73.556 73.826 74.089 74.345 74.594 74.837 75.073 75.304
7.590 7.591 7.592 7.727 7.933 8.127 8.288 8.416 8.517 8.598 8.662 8.715 8.758 8.795 8.826 8.853 8.876 8.897 8.915 8.!)31 8.946 8.960 8.972 8.984 8.995 9.005 9.014 9.024 9.032 9.040 9.048 9.056 0.063 9.070 9,077 9,084 9.091 9.097 9.104 9.110
61.070 61.462 61.838 62.198 62.545 62.879 63 .20 1 63.512 63.813 64.104 64.385 64.659 64.924 65.182 65,433 65.677 6.5 914 66.146 66.372 66.592
4100 4200 4300 4400 4500 4600 4700 4800 4900 5000
66.808 67.018 67.223 67.424 67.621 67.814 68.002 68.187 68.368 68.546
75,529 75.748 75.963 76.173 76.378 76.579 76.776 76.969 77.158 77.343
9.116 9,123 9.129 9.135 9.141 9.147 9.153 9.159 9.164 9.170
TABLE VI1 THERMODYNAMIC FUNCTIONS O F Pc(g) IN IDEAL GASST.4TE F Q - Hog , -(-T-)
T,O K . 273.15 298.15 300 400 500
600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 3100 3200 3300 3400 3500 3600 3700 3800 3900 4000 4100 4200 4300 4400 4500 4600 4700 4800 4900
6COO
SQ,
CPQ,
oal. deg. -1 mole-1
oal. deg. -* mole-1
oal. deg. -1 mole-1
44.064 44.675 44.718 46.738 48.325 49.643 50,775 51.771 52.661 53.467 54.205 54.886 55.518 .56.108 56.663 57.186 57.682 58.153 58.602 59.032 59.444 59.840 60.221 60.589 60.944 61.288 61.622 61.945 62.259 62.565 62.862 63.151 63.434 63.709 63.977 64.240 64.496 64,1746 64,991 65.231 65.465 65.694 65.919 66.140 66.355 G6.567 66.775 66.978 67,178 67.374
51.038 51.661 51. $06 53.802 55.496 56.930 58.177 59.280 60.270 61.167 61.988 62.747 63.452 64.113 64.737 65.327 65.890 66,428 66.945 67.441 67.920 68.383 68.831 69.264 69.684 70,091 70,486 70.870 71 ,242 71. GO4 71.955 73.296 72.628 72.951 73.264 73.569 73.865 74.154 74.435
7.090 7,149 7.154 7.446 7.741 7.989 8.184 8.338 8.462 8.568 8.667 8.765 8.867 8.977 9.094 9.218 9.349 9.483 9.618 9.762 9.883 I O . 008 10.127 10,237 10.338 10.429 10.510 10.580 10.641
74.708
74.975 75.234 75.487 75.733 75.974 76.209 76.438 76. 661 76.880 77.093
IO.G92 10.733 10.766 10.791 10,808 10.819 10.823 10.822 10.817 10.807 10.793 10.777 10.75; 10.736, 10 .7 18 10.688 10.662 10.63.5 10.607 10.579 10.551
ROBERT1,. ]'OTTER
854
;1ND VINCENT
TABLE VI11 THERMODYNAMIC FUKCTIONS OF PF,(g) IN IDEAL GASSTATE
("--""), T
T ,OK.
cal. deg. -1 mole -1
273 15 298 15 300 400 500 600 700 800 900 1000
SX . 887
1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
S', cal. deg. -1 mole - 1
CPO,
cal. deg. -1 mole-]
63.949 65.153 65.240 69,540 73.195 7(i ,352 79.118 81.571 83.770 85.762
13.47!) 14.028 14.067 15,792 16,929 17.6i9 18,188 18.544 18.800 18.991
71.864 73.244 74.535 7 5 .749 76.892 -I ,974 79.001 79.978 80.908 81.798
87. 579 89 .240 90,794 92.229 9 3 . 570 94.828 96,012 95.131 98.191 99.198
19.136 19.248 19.337 19.408 19.466 19.514 19.551 19.588 19.616 19.641
2100 2200 2300 2400 2500 2600 2700 2800 2900 3000
82.650 83.466 84.251 85.006 85. 733 86,455 87.118 87.769 88.403 89.018
100,157 101.072 101.947 102.786 103.590 104.364 105.109 105.827 106,521 107.191
19.662 19.681 19.697 19,711 19.723 19,735 19,745 19.753 19.761 19.769
3 100 3200 3300 3400 3500 3600 3700 3800 3900 4 000
89.615 90. 105 9 0 . 758 91.305 91.838 92.357 92,863 93.356 93,837 94,307
107,839 108.467 109.076 109.667 110,240 110,798 111 341 111.869 112.383 112.885
19,775 19,781 19.787 19.792 19.796 19.800 19.804 19.808 19.811 19.814
4100 4200 4300 4400 4500 4600 4700 4800 4900 5000
94.i66 $15,215 95.654 96. 083 96.504 96.915 97.318 97.714 98.101 08 481
113,374 313.852 114,318 114.774 115,220 115.655 116.082 116.490 116.908 117.30!1
19.817 19,819 19,822 19.824 19.826 19.828 19.830 19.832 19.833 19.835
54,782 54.846 57 ,998 60 681 63.036 65,140 67.043 68.782 70.382
ral. deg. -1 inole - 1
cal. deg. -1 mole-'
273 15 298 1.5 300
41 :385 42 0!)4
49 455
42 145
50 222 50 276
400
44 525
52 982
55 57 59 61 62 64
333 455 404 215 907 493
11.115 12.172 13.134 13.988 14.732 15,371
1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
54 55 56 57 58 59 59 60 61 62
107 431 403 327 211 056 867 646 396 118
65 67 68 69 71 72 73 74 75 76
984 390 717 973 161 296 373 400 381 319
15.917 16.382 16.778 17.117 17.407 17.656 17.872 18.059 18.223 18,366
2100 2200 2300 2400 2500 2600 2700 2800 2900 3000
62 63 64 64 65 65 66 67 67 68
816 491 143 775 388 983 560 122 668 200
77 $8 78 79 80 81 81 82 83 83
218 081 910 708 177 218 934 626 296 945
18.492 18.603 18,702 18.790 18.869 18.939 19.003 19,060 19,112 19.160
3100 3200 3300 3400 3500 3600 3700 3800 3900 4000
68 69 69 70 70 71 71 72
718 223 716 197 666 125 574 013 7 2 442 72 862
84 574 85 184 85 777 86 353 86 913 87 458 87 989 88 507 89 012 89 504
19,203 19.242 19.278 19.311 19.341 19.370 19.395 19,419 19.442 19.462
4100 4200 4300 -1400 4500 4600 4700 4800 4900 5000
73 73 74 74 74 75 75 75 76 76
89 985 90 455 so 914 91 362 91 802 92 231 92 652 93 064 93 468 93 854
19.482 19.499 19.516 19.532 19.546 14.560 19.573 19.585 19,596 19,607
THERMODYSAMIC
TABLE X FUNCTIOXS O F P4(g) I N IDEAL GAS -
T , OK.
274 678 073 461 842 215 581 941 295 642
(ye),
cal. deg. -1 mole-'
1 100 1200
oo2
1300
74 19-1 75 657 77 021
mole-1
I
457 115 591 932 170 323
630 87% 891
CPO,
C R ~ .deg. -1
8 8 8 9
46 48 49 50 52 53
54 55 55 59 62 64 66
Fa - Hoo ,
\-01. 65
500 600 700 800 900 1000
273 15 298.15 300 400 500 600 700 800 900 1000
TABLE IX THERMODYSAMIC FENCTIOSS OF PH,(g) IS IDEAI. Gas STATE T, OK.
s.DISTEFASO
602 578 048
119 083 671 967 69 030 70 902 7 2 61,i
so,
STATE
CPO,
cal. deg. -1 mole-'
c d . deg. - 1 mole-'
65 541 66 926 67 025 71 876 7 6 877 79 256 82 167 74 722 86 993 89 038
15,539 16.075 16 111 17 526 18 293 18 743 19 038 19 219 19 352 19 448
It0 895 92 596
19 521 19 570
04 10.1.
19 619
1100 1500 1600 1 TOO 1800 1!100
2000 2100 2200 2300 2400 3500 2fi00 2700
2800 2!)00 :3000 :3 100
:3200 :3:300 3400 3500 3600
3700 3800
78 299 70 499 80.632 81. 703 82. 720 83,688 84.611
95 96 08 99 100 101 103
85.493 86 338 87,140
103 616 104 53G 105 416 106 258 107 OG7 107 8-13 108 591 100 312 110 007 110 679
19.775 1 9 ,$83 19.791 19.797 19,803 19,809
111 329 111 959 112 569 113 161 113 736 114 295 114 839 115.368
19.827 19.830 19,833 19 ,8335 19.837 19.839 19.841 19.843
87.928 88.677 89 . 399 no.096 90 . 770 01 421 0 2 0,i' ! ) 2 ,Mi4 9s '257 93 . 8333 0 4 , 398 04.!437 95 167
95.983 %i. 487
620 077 248 1-13 5T1 tj38 ti52
19.654 1 9 .A81 19.704 19,723 19.739 19.753 19,705
19,813 19,817 19.821 19,824
:1000 4000
96 !)Ti 07 456
115.883 116.386
19.844 I!) 845
4100 4200 3300 4400 4500 4600 4700 4800 4900 5000
97 924 98 381 (I8 828 99 264
116 ST(; 117 : 3 < 3 I 17.8'21 118,277 118 723 119 160
19.847 19 848
09 100 100 100 101 101
692 110 520 922 31B 702
I 9 849
1!).850 I!) 851 I!) 852 19 853 1 0 . 85-1 19.855 19 8%
IIn.587 120 005 120.114 120.815
TABLE XI HE.irrs OF FORMATIOS O F SIMPLEPHOSPHORUS LIOLECCLES WITH P(+ p , 0°K.) AS STASDARD STATE 1HoO. cal./mole
P
PS PN PO PC PF3 PH3 P4
-_ a , 370 I
34,600 22 020 -5,710 107, 380 - 2'20,600 4,100 l5,7(iO ~
AH%,.,^, cal.,'niol?
--
, a , 580 :3-1,250 21 , 790 -5,780 107 ,940 -2",950 2,210 14.0Kl
AiHIGH TEMPERATURE DROP CALOKIJIETEK. THE HEAT C~iP~iCITIES OF TASTALUM ASD TUSGSTEN BETWEES 1000° &%XD30003K.' BY MICHAEL HOCH?ISD HERRICK L. JOHSSTOY The Department of Cheinzstry, Ohio State Unzzersaty, Coliinibiis Ohio Recetied Dcccnibri 1 4 , 1Qfi0
h high temperature drop calorimeter, operating under high vacuum, using radiofrequency heating and a Bunsen calorimeter, has been developed to measure heat contents between 1000 and 3000°K. The enthalpies of tantaluiii and tungsten have been measured betn-een these temperatures. The sources of experimental error, such as temperature measurement and cooling of the sample during the drop, are discussed in detail and their magnitude determined experimentally.
Introduction Apparatus 1. Furnace.-The furnace is shon-n in Fig. 1. The Accurate heat content measurements were is supplied by a 20 KT4; General Electric heater limited heretofore to 1iOO', the maximum tem- power through water-cooled copper tubings which are introperature permissible for platinum, which must be duced through an insulation3 into the fnrnace. The sample a is heated in the center of the work coil. used for the heated parts (resistance heater, sample container) in order t o enable the equipment to be It is connected through a tantalum wire to an iron core b To which is held in place 11)- a 1G00 gauss magnet operated in air. avoid swinging of the sample, a centering disk d is mounted The calorimeter described here operates under rigidly onto t,he wire which presses against a tantalum t'ube high vacuum, uses radiofrequency heating, and e. The brass cylinder f , which can be raised or lowered by reel g, is used to lift the iron core and sample into the only limitation t o temperature is the need of a turning place. The t h r w magnets m , of I600 gauss each, serve t o solid material for t h r container. slow don-n and stop the iron core and sample. On the bottom of the furnace is n radiation shield h. The Tantalum arid tungsten were used for the first temperature is meaeurtd through the window i xith a disenthalpy determinations, because they are the only appearing filament optical pyrometer. .Z 3C24 gage V , metals whose melting points are higher than 2700' mounted on the side of the furnace, is used to measure the knd thus are s o l i d s over the whole temperature pressure. The ralorimeter and furnace :ire evacuated range investigated. No compounds were studied through a 3" diameter tube and a liquid air trap with :I 260 oil diffusion pump. Between the oil diffusion at first, because of possible reactions with the WMF pump and the mechanical pump is a rubber diaphragm tantalum container a t the highest temperatures. valve k which is shut when helium is introduced into the (1) This work was supported in part by t h e Office of Naval Research under contract v i t h t h e Ohio State University Research Foundation. (2) Department of Illetallurgical Engineering. University of Cincinnati Cincinnati 21, Ohio.
furnace. The bellows n connects the furnace t o the calorimeter. (3) hf. Hoch, Rev. Sci. Instr., as, 651 (1952). (4) The magnets were supplied b y T h e Indiana Steel Products Co.. Valvaraiao, Indiana.
