A SYSTEM OF PHYSICAL CHEMISTRY Atomic Frequencies by Debye's Formula. Element. IO-I3-
MOLECULAR HEATS OF POLYATOMIC SOLIDS 77 where F^ and F.2 are the Debye /8V2^ C„=F,(^)^F,(^^) and Einstein functions or atomic heat expressions respectively. In the case of KCl, ^v^ =166 (obtained from the melting-point formula), and ^v^ = 2i3"5 (obtained directly from the Reststrahlen observations). The following table, taken from Nernst's Theory of the Solid State, gives the values of the Einstein and Debye portions of the molecular heat in the case of KCl. The column headed "correction" contains the quantities which must be added to 2C1, in order to give 2(Zp, the molecular heat at constant pressure :— T. KCl.y8v2 = 213-5; ^y\ = 166.