RUDOLPHSPEISER, HERRICR L
1.112
~ ~ ~ ' ' F R IIr I( J4\ ~ TRO\I
illr
~RlO(rT'-IL r,\i'iiK4r~)R'i
PAUL RLACKBVRN
Vol. 7 2
1\2> I t I P ~ ~ t P A R I 1 f E YO TF CHEMISTRY, OHIO
STATE ~'\IVERSITY]
JOHNSTON AND
Vapor Pressure of Inorganic Substances. 111. Chromium between 1283 and 1561X. '
The only available data i i i tlic literature ( u i tlit: vapor pressure of chromium are those of Raur and Brunner.2 However, their data show a decided temperature trend i n the calculated values of 2~71,'. 'The vapor pressure of chroniiurn has therefore been redetermined a t this Laboratorv by the Langniuir method. References to the method, and description of our own techniques, ha1.e heen given in earlier papers from this Laboratory. Experimental
-
The measurements consisted of determining the rate at which a chromium surface ev.aporated into a vacuum. Pure chromium was prepared by vacuum fusion4 in an arc furnace fitted with a water-cooled copper crucible as an anode and with a tungsten electrode as a cathode. Spectroscopic analysis showed 99.7% purity of the product; the 0.370 impurity was oxygen. There was no trace of either tungsten or copper. The sample was in the form of an annular ring of approximately 2.50 cm. 0 . d., 1.02 cm. i. d. and 0.192 cm. thick. The sample was placed in a metal cePb after thorough outgassing and was then heated by high frequency induction under a vacuum of the order of mm. The outgassing was especially important for chromium because of its strong tendency t o oxidize. Temperatures were measured under black body conditions by a k e d s and Northru;, disappearing filament optical pyrometer which had been calibrated against a standard lamp furnished by the National Bureau of Standards, Pyrometer reading;; werc reproduced t o
Results and Discussion Experimental results are summarized in Table I and plotted as log P DS. 1, 7' in Fig. 1 . The effective internal areas of the annular rings and the
c;
1
I*
' P
, ..:
I
-
*!
-
8
cffwtive tiiiie :tt the teniperature of measurement were tietermined as described in the first paperDa of this series. The thermodynamic functions, also calculated as before, are given in Table 11; the thermal data for solid and gaseous chromium were taken from the l i t e r a t ~ r e .The ~ computedvalues of AH,:', the heat of sublimation a t O"K., are constant to 93.50 kcal. to within 0.1 kcal. and show no trcnd with temperature. 'TABLE
iemp., OK.
I .
.~. . .
43 44 44 44 44 44 44 44 44
IJ
__ .
work was supported i n part by the OEce of ,Varal Research under con tract with the Ohio State Eniversity Research
October 17-21, 1948, Cleveland. Ohio. (4: D 1. hlacPhrtiori. Ph 1) 'Thesis, Ohio S t a t ? V n i v e r i i t v 19IB.
2.8354 X 7 9337 x 1 5338 X 2 4027 x 3 5230 X G 3549 x 8 3057 X 1 1447 X 1 9636 X 1 9558 X 2 0152 X 3.0823 X 4 8831 X 5 3168 X 1.9252 X
92
9 91
06 I6
10 08
24 27
26
38 43
47 54
10 10 10 10
18
a0
42 10 47 10 52 10 60
44 72
10 0 2 10 64 10 68 10 78 10 83
4 4 40
11 OI
44 55 44 57 44 61 44 69
( 1 ) This
Foundation. ( 2 ) E. Barir and K. Brunner, Heiv. Chim. Acta, 17, 958 (1934). JOWR(3) (a) R . B. Holden, R . Speiser and H. I,. Johnston, THIS SAL, 70, 3897 (1948): (I).! R Speiser and H. L. Johnston, Preprint Xo. 11. Thirty-first Couvention of the American Society for hletals,
Eyap. rate, g./cm.Z/sec.
1283 8.44 296.5 1321 9.22 114.2 1346 17.92 115.7 1366 13.83 56.55 1377 9.08 25.5 1405 16.19 2 5 . 4 1418 20.87 2 5 , 2 1432 29.19 25.4 1452 63.44 2 6 . 7 1455 52.72 26.9 1462 55.88 2 7 . 6 1470 72.94 2 3 . 9 1497 122.51 24.8 1507 135.83 2 5 . 5 152.73 7.79
1f ) .
time, min.
los.;, mg.
Fig. 1 . --\,apor pressure of chroniiurn. .
I
VAPORPRESSURE OF CHROMIUM \{'eight BE.
38.89 36.82 35.49 34.58 33.81 32.62 32.18 31.43 30.35 30.35 30.29 29.49 28.50 28.33 26.74
Pressure, atm.
lo-* 3 1768 X 10-9 9 0197 X lo-' 1 7602 X 10-7 2 7777 x 4 0892 X 10-7 7 4533 x 9.5097 X 1O-O 1.3549 X 2 3406 X 2 3330 X 2 4103 X lo-' 3 5991 X lo-' 5 9097 X 10-o 6 4561 X 10-6 2.3793 x
8.4980 8.0448 7.7645 7.5563 7.3884 7.1277 7.0318 6.8681 6.6306 6.6319 6.6180 6.4438 6.2284 6.1900 5.6236 Mean
93.53 93.53 93.51 93.65 93.06 93.54 93 7u 93 6 2 93.3.; 93 53 93 89 93 23 93 4 3 93.77 93.04 93.50
10-8
10-9
io-* lo-'
10 'I 10-7
lo+ 10-8
i 0 18 -- ( 5 ) R k; Kelley, Contribution to the Data on Theoretical Metal Iurgy, Bureau of Mines Bull N o 383, 1935 (gaseous chromium). E Richert, C W. Beckett, and H. L. Johnston,;Techn. Report No. IO.' 4C 49 1 2 100 Der I , 1449 (solid chromium).
__
Sept., 1950
THECOMPRESSIBILITY AND EQUATION OF STATE FOR BUTENE
Our value of 93.50 kcal. for A% compares with the values, 78.3 kcal., obtained by Baur and Brunner2; 80 kcal., reported by Wagman, Rossini, Evans, Levine and Joffea; and 88.8 kcal., given by Kelle~.~ The latter value is based on a single measurement a t the boiling point. Table I11 gives values for the sublimation heats of the first series of transition elements. These values differ considerably from those in the table given by Seitz,' which were based on older data, but still support the contention that cohesive forces are higher for metals with partially filled d shells than for those with completed d shells. Chromium fits reasonably well into the general scheme. Least square treatment of the vapor pressure data for chromium yields the equation
4143
TABLE I11 AfIi
HEATSOF T H E SERIESOF TRANSITION ELEMENTS
V A L U E S FOR T H E SUBLIMATION
Atomic
no.
22 23 24 25 26 27 28 29 30
Element
Ti8 \:'
Cr Mn12 Fe'O Cog
Si" Cul0 Zn6
A@. kcal.
Electronic structure
ls2 2s2 1s' 2s2 ls2 2s2 ls2 2s2 Is2 2s2 ls2 2s2 Is2 2s2 Is2 2s2 Is2 2s2
3s2
2p6 2p6 2p6 2p6 2p6 2p6 2p6 2p6 2p6
3s' 3s2 3s2 3s2 3s2 3s2 3s2 3s2
fi1Rs.r
3d2 4s2 111.0 3d3 4s2 106.0 3d' 4s' 93.5 3d5 4s2 , , 3d6 4s2 9 6 . 0 3d7 4s2 9 3 . 0 3d8 4s2 101.1 3dI0 4s' 80.7 3dl0 4s2 31.1 ,
value of AH: with Kelley's free energy functions for solid and gaseous chromium, the vapor pres7.415 is sure equation log P a t , = - (20,434/T) log Pat, = -(20,473/T) 4-7.467 obtained. Like the other transition elements Summary of similar crystal structure with unfilled d shells, The vapor pressure of chromium has been chromium has a relatively high energy of submeasured over the temperature range 1283 limation. to 1561'K. by determining the rate a t which the 71, 4040 (8) H. J. Blocher and E. I. Campbell, THIS JOURNAL, metal surface evaporates into a vacuum. The (1949). (9) S. Dushman, "High Vacuum Technique," John Wilty and values have been calculated from the in- Sons, Inc., New York, N. Y.,1949. dividual vapor pressure points and show no ap(10) A. L. Marshall, R. W. Dornte and F. J. Norton, THISJOURpreciable temperature trend, the average value NAL, 69, 1161 (1937). (11) H.L. Johnston and A. L. Marshall, ibid., 62, 1382 (1937). being 93.50 * 0.18 kcal. By combining this
+
a
(6) D.D.Wagman, F. D. Rossini, W. H. Evans, S. Levine and I. Joffe, National Bureau of Standards (1949) Series I, Table 49-1. (7) F. Seitz, "The Modern Theory of Solids," McGraw-Hill Book Co., Inc., New York, N. Y.,1940, pp. 3, 427-429.
[CONTRIBUTION FROM T H E
DEPARTMENT OF
(12) The heat of sublimation of manganese is not listed here since its crystal structure is considerably different than that of the other elements in this list.
COLUMBUS 10, OHIO
CHEMISTRY,
RECEIVED MARCH17, 1950
MASSACHUSETTS INSTITUTE
OF TECHNOLOGY]
The Compressibility of and an Equation of State for Gaseous 1-Butene BY JAMES A. BEATTIE AND STANLEY MARPLE,JR.
I n a recent paper' we presented measurements of the vapor pressure, ortbobaric liquid volume and critical constants of 1-butene made in 1941. The same loading (6.7122 g.) of the sample was used to determine the compressibility2 of 1butene from 150 t o 250'. The substance was confined in a bomb with a glass liner.2 Roper3 measured the volumetric behavior of 1butene a t low pressures from -75' to +70° from which he derived an equation for the second virial coefficient for the range -30 to +BO". Aston4 and co-workers computed the second virial coefficient for the temperature range -71 to -6' from measurements of vapor pressures, (1) J. A. Beattie and S. Marple, Jr., THIS JOURNAL, 72, 1449 (1950). (2) For the last paper in this series see J. A. Beattie, S. Marple, Jr., and D. G. Edwards, J.Ckem. Phys., 18,127 (1950). For a description of the apparatus and method see J. A. Beattie, Proc. Am. Acad. Arts and Sci., 69, 389 (1934). (3) E.E.Roper, J . P h y s . Chem., 44, 835 (1940). (4) J. G.Aston, H. L. Fink, A. B. Bestul, E. L. Pace and G. J. Szasz, THIS JOURNAL, 68, 52 (1946).
heats of vaporization, and orthobaric liquid volumes. In the range -31 to -6' these values were in good agreement with those computed from Roper's equation. Olds, Sage, and Lacey6 measured the compressibility of 1-butene from 38 to 171Qand to about 700 atmospheres. The 1-butene used in the present investigation was furnished by the Linde Air Products Company through the courtesy of Dr. J. M. Gaines, Jr. The increase of vapor pressure with decrease in vapor volume and the slope of the isotherms in the two phase region near the critical point indicated' the presence of a moderate amount of impurity which did not seem to be a permanent gas. Above 200' 1-butene polymerizes rather rapidly. As is the usual procedure we measured the pressures along each isotherm for increasing densities starting with 1 mole per liter. After the completion of the isotherm we remeasured the ( 5 ) R. H. Olds, B. H. Sage and W.
301 (1946).
N.Lacey, I n d . Eng. Chem., 38,
