215 1 'r.4ULE
11
I I EAT CONTENTS (CAL./MOLE)A N D ENTROPIES (CAI,./DEG.MOLE)A B O V E 298.16 "I.;. I . "E;.
$00
>(io 600 700 800 !)Oil 1000 1 l!)O
12011 1;3! 10 1400 I500
l6On 1700 1800
AIzTiOh
HT - 11z.a.~S'r - S?SS.IS HT -
3,600 7,620 11,930 16,420 21,020 25,700 :30,450 :15,2m 40,180 45,150 50,180 55,260 60 ,370 65,490 70,620
10.35 19.30 27.16 34.07 40.22 45.73 50.78 .55,33 59.59 63.57 67.30 70.80 74.10 77.21 80.14
FezTiOs HZS.16
4,330 8,740 13,300 18,010 22,870 27,860 32,9G!) 38, 1:10 43,3:10 48, 550 53,800 59,080 64,400 69,760
ST
-
12.46 22.29 30.60 37.86 44.35 50.23 35. 60 ($0, 5.3 65.05 ijY ,2:3 73 . I 2 7 6 . 76 80.20 83.45
magnetic inversion point a t 900'K. which is absent for titanomagnetite. Yfeasurements of titanomagnetite beyond 1513°K. were hampered because the substance began to attack the platinum-rhodium capsule. Higher temperature results are considered unsound and therefore are not reported. Table I1 gives smooth values of heat content and entropy increments above 295.16'K. a t even 100' intervals, for use of those who make thermodynamic calculations by the tabular method. The entropy increments were calculated to match the heat content values by the method of Kelley.13 The heat content data are represented by the following equations. The temperature range of validity and average deviation from the measured values are indicated in parentheses. (13) K. K. Kelley, U. S. Bur. M i n e s Bull. 470 (1949).
[CONTRIBUTION FROM
TKE L O W
.%%.lG
FerTiOd
- H 2 ~ 8 . 1 6 ST - . h S . I 6 3,750 IO. 80 7,610 19 40 11,640 2fj. 74 15,850 33 . 2'3 20,220 39.06 24,740 44.28 29, 400 49.29 34,210 53.87 39,180 58.20 34,350 62.34 49,160 66.35
