Contributions to the Data on Theoretical Metallurgy: [Part] 11. Entropies of Inorganic Substances: Revision (1948) of Data and Methods of Calculation Page: 43
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ENTROPIES OF INORGANIC SUBSTANCES AT 298.16 0K.
Moore (364) has compiled spectroscopic-energy-level data for Co (g).
At 298.160, four energy levels are effective, 4F912, 4F7/2, 4F5/2, and 4F3/2.
The quantum weights are 10, 8, 6, and 4, respectively, and the term
values are 0, 816.0, 1,406.8, and 1,809.3 cm-'. These states add
4.739 to the Sackur equation to make S~,98,8=42.890.01 for Co(g).
Chloride.-The heat capacity of CoCl2(c) was measured by Miljutin
and Parfenowa (357) (110-190) and Trapeznikova, Shubnikov, and
Miljutin (491) (130-1310). Their data yield S29816=25.4+1.5, of
which 0.10 is extrapolation below 11.20.
Iodide.-Miljutin, Parfenowa, and Esselson (858) (160-1290) have
reported heat-capacity data for CoI2(c). These data are inadequate
for calculation of the entropy.
Ammoniated Cobalt Halides.-Ziegler (515) (1070-3210) has meas-
ured the heat capacities of CoCl3. 6NH8, CoI2-6NH3, and CoI . 6NHa.
The data are insufficient for entropy calculations.
Element.-Data are not available for obtaining the entropy of
Cb(c). However, the entropy of Cb(g) may be obtained from spec-
troscopic data compiled by Moore (364). The states to be considered
are 6D1/2, 6D3/2, 6D52, 6D7/2, and 6D9/2, with quantum wieghts of 2,
4, 6, 8, and 10 and term values of 0, 154.1, 391.9, 695.3, and 1,050.3
cm.-1, respectively. The result is that 4.949 must be added to the
value given by the Sackur equation, making S298s.16=44.46 0.01
for Cb (g).
Element.-Several investigators have measured the heat capacity
of Cu(c): Aoyama and Kanda (29) (820-2740), Dockerty (129, 130)
(280-2990), Eucken and Werth (154) (830-2160), Giauque and Meads
(182) (140-3010), Keesom and Onnes (265, 266) (140-90), Kok
and Keesom (303) (10-200), Maier and Anderson (344) (530-2950),
and Nernst (373, 376) (230-880). Using all the data, the entropy
is S98.18=7.970.02. The extrapolation is negligible (<0.0001
The entropy of Cu(g) may be obtained from the Sackur equation
with R In 2 added to account for the quantum weight of the lowest
energy level. The result is S98s.16= 39.750.01.
The entropy of Cu2(g) is estimated as S298.16--58.01.0. This
result probably is more reliable than the estimate of Randall, Nielsen,
and West (395), S2s98.18=58.9.
Cupric Ion.-Latimer, Pitzer, and Smith (325) have obtained
--25.9 3 and -26.61, respectively, as values of the entropy of
Cu++(aq.) from data for the reactions Cu(c) +2H+(aq.)= Cu++(aq.)+
H2(g) and Cu(c)+2Ag+(aq.)=Cu++(aq.)+2Ag(c). Their selected
value, S98.16,=-26.5 1.0, also is adopted here.
Oxides.-Millar (362) (750-2910) measured the heat capacity of
Cu2Q(c). The heat-capacity curve for this substance is abnormally
flat, making extrapolation quite uncertain. There is calculated
S98.1=--24.11.5, of which 7.85 is extrapolation below 70.80.
Clusius and Harteck (100) (300-2000) and Millar (362) (710-3020)
have measured the heat capacity of CuO(c). The latter found a
,curious, nonreversible region centered around 2200 on which more
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Kelley, K. K. Contributions to the Data on Theoretical Metallurgy: [Part] 11. Entropies of Inorganic Substances: Revision (1948) of Data and Methods of Calculation, report, 1950; Washington D.C.. (https://digital.library.unt.edu/ark:/67531/metadc12637/m1/47/: accessed April 21, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.