Correction to Dulong-Petit Law

Original Data of Dulong & Petit

Data shown in red have large errors!

Atomic
Symbol

S

Co

Te

Pt

1819
SpHt

.1880

.1498

.0912

.0314

1819
AtWt

32.2

39.4

64.5

178.6

1819
Cp

6.05

5.90

5.88

5.98*

1986
Cp

5.62

5.93

6.10

6.18

1986
AtWt

32.1

58.9

127.6

195.1

1986
SpHt

.175

.1006

.0482

.0317


* The product of 0.0314 and 178.6 is 5.61 not 5.98
The Dulong-Petit data were satisfactory for Fe, Ni, Cu, Zn, Ag, Sn, Au, Pb, and Bi


Many people believe that Dulong and Petit used their law to correct atomic weights of some elements. The 1819 Dulong-Petit paper in French was their only report on this subject, and reading this or the English translation of the discussion portion gives no hint that they made any corrections to atomic weights. Indeed, the above-noted errors in cobalt and tellurium indicate that they missed a great opportunity.

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