March, 1960
NOTES TABLEI COMRUSTION DATA Sample wt., g. vacuum
0.9934 1 .OOO6 1.0010 1.0062 0.9889
- AH00
kcnl./mole
AHP. kcal./ inolr
645. G4 644.8G 646.44 644.98 645.76
mean 645.5 f 0 . 3 30.7 [Co(NH3)5N3I( N3)2
1 .oO09 1 .m 0.9998 1.0011 1.0048
562.59 562.73 563.00 5K3.8G 561.70
m c a n 5 6 2 . 8 2 ~0 . 4 5 0 . 4 cis- [Co(NH,),( N2)2 1x3
0.5001 ,5048 ,5109 ,5189 ,4991
500.3G 500.36 500.51 500.42 502.22
mean 500.8 f 0 . 4 9 0 . 9
!rans-[Co(?;H3I4(N.r)21N3 0.4976 ,497: 5118 ,5137 ,5096
502.04 501.70 500.42 499.20 498.03
379
of the rare earth oxides. The method, involving the determination of the heat evolved from the c*oml)ustionof a weighed sample of the metal in a homb calorimeter at a known initial pressure of oxygen, has been d e s c r i b ~ d . ~The same units and conventions are used here. Thulium Metal.-Thiilium metal waa obtained from two sourccs, Ames Laboratory, A.E.C., Ames, Iowa (Ames) and The Michigan Chemical Co., Saint Louis, Michigan (M.C.). The analyses of the samples wcre made a t this Laboratory :ind are summarized in Table I. ANALYSIS O F
TABLE 1 THULIUM hIETAL--yo IMPURITIES
1% 0 N M g Ca Ta Sm 0.009 0.020 0 006 0.04 0.10 .. 1.0 0.075 0 . 0 3 7 0.230 0.009 0.05 0.10 1.05
C
Ames M.C.
0.090
..
No other metallic impurities were detected spectrochemically. The thulium metal from Ames t.hus contained about 1.27% impurities, the M.C. metal, 1.55%. Assuming that the non-metallic impurities were combined with the thulium ;is the carbide, hydride, nitride and oxide, the Ames material was 96.69 mole 7. mctal and the M.C. material, 93.66 mole ‘7..(Atomic weight T m = 168.94.) The X-ray lattice constants for the M.C. material were slightly greater than i.xpected, possibly indicating the presence of rare earths of lower atomic number in solution. Combustion of Thulium.-A 10 mil diameter fuse wire of magnesium was used to ignite the thulium. The thulium WLS burned on sintered discs of thulium oxide in oxygen a t 25 atni. pressure. The metal showed no gain in weight when rlxposed to O2 a t 25 atm. pressure for one hour. Combustion varied from 88.67 to 99.67% of completion. The :hveragc initial temperature was 25.2”. The two series of x1n.s are summarized in Table 11.
mean500.3 i- 0 . 8 90.4
‘co(xH3)3(N8)1j
0.4200 0.4593
TABLE I1
“4.2 402.1
T H E I I E A T OF COMBI:hTION OF ‘ h C L 1 C X
Wt.
mean403 2 f 1 0 95.7
[CoINH3)S(N3)3j, -403.2 f 1.0 kcal. mole-’. The heats of formation of these compounds were calculated using -6E,,316 and -94,050.6 (at. wt. C = 12.011) cal. mole-’ as the heats of formation of water and carbon dioxide, respectively. These values are listed in the last column of Table I. As some difficulty was encountered in obtaining tlomplete combustion preliminary calculations were made of the standard deviation of the mean for each set of determinations and any runs which exceeded the mean value by more than three times the standard deviation were discarded. Because of the difficulties mentioned above in the preparation of‘ [ C ~ ( r \ j H ~ ) ~ ( nand T ~ the j ~ ] fact that {mly two acceptable determinations were made of its heat of’ combustion, the reportrd value should be vonsidered preliminary. THE HEAT OF COMBUSTION OF THULIUM’ BY ELMEX J’. HUBER,JR., EARLL. HEAD.4ND
Mg, nig.
2 1404 i 9087 2 3009 I . 7425 2,0488 2 1123
7.00 7.29 5.15 0.94 7 11 b j 13
Wt. TninOs. iz.
Joliirs: de.il.
AT, ’A.
totdl
70.2
Amrs 100zo.z i . m o
67.6 5!L0 60.6 33 8 40 8
10019 3 10017.0 10017.5 10018 2 10014 C i
1.1477 1.3117 0.9907 1.1685 > 2060
fSnrray from Yirinx, ‘y, j. :., g. 15.1 10 A
5628.2 5658 1
7.7
5619.2
10.3
5625.8
15,+
5630 4 5638 9
:3.8
AV.
TkV.
from mean
5633.3
Stand. dev.
M.C. 2.2753 1.9130 2.0456 2 . n,?1c, 1 9019 2.2207 2 2905 2 03x5
6.75 7.09 7.31 7.42 A.20
ti 39 A 28
57f;
49.6 46.8 40.1 4~ 3 39 1 39 1 33 1 471;
10014.C, 1.2694 10013.9 1.0750 10013.7 I 1462 10013.7 1.1353 10011 9 1.0642 1onii.g 1.2381 10010.3 1.2751 10014.1 i.1383
12.5 10.5
11.2 12 o 12 5 11 7 :fi 7 TO5
AV.
Stand. dev.
5508.5 1 7 5530 3 2 0 . 1 5517.3 7 1 5499 4 10.8 5515 1 4 . 9 5505.7 4 ,5 5500 3
9 9
5,5049 519 2
.7 :5
$ 0 3 R5
The two values must be corrected for tlie impwitips present.
This paper is a continuation of the series? reporting measurements of the heats of formation
Correction for Impurities.-The calculated percentage composition of the thulium metal (Ames) by weight is as follows: T m metal, 97.77; TmH2* 0.76; Tm203, 0.16; TmN, 0.08; C, 0.09; Mg, 0.04; Ca, 0.10; Sm, 1.0. The heat) of combustion of this thulium metal correct,ed for impurities is 5,595.4 jouies/g. or 0.67% smaller than t,he un-
This work was done under the auspices of the A.E.C. ( 2 ) See E. .J. Huber. Jr., E. L. Head and C. E. Holley. .Jr., THIS JOCR~AL 61, . 1021 (19.571, for reference to earlier paper8 in the series.
(3) E. J. Huher. Jr., C. 0. Mathews and C. E. Holley, Jr., J . Am. Cham. Soc., 77, 6493 (1955). (4) The specific heat of TrnzOa is estimated as 0.20i o u l e i d d e g .
CHARLES E. HOLLEY, JR.
L o s Alamos Sctentipc Laboratory of the Universify o f California, Los
Alamos, N e w Mezico Received October $ 1 , 1969
‘1)
NOTES
380
corrected vatlue.6 If the combustion products, HzO, NO2 and Con, are assumed to re
