Dulong-Petit law, found in
1819 by
Pierre Louis Dulong and
Alexis Thérèse Petit, states the classical expression for the
specific heat capacity of a
crystal due to its
lattice vibrations[?]. The result is extremely simple: regardless of the nature of the crystal, the specific heat capacity is equal to 3
R/
M, where
R is the
gas constant and
M is the
molar mass. Despite its simplicity, Dulong-Petit law offers fairly good prediction for the specific heat capacity of solids with relatively simple crystal structure at high
temperatures. It fails, however, in the low temperature region, where
Debye model[?] should be used instead.
See also: Stefan-Boltzmann law