ACCURATE MIXTURE-MODEL DENSITIES FOR D2O

Recently, we presented arguments strongly supporting a type of mixture model-actually, a mixed bonding model-for liquid water (H2O) through an analysis of its extremely precise temperature-dependent density dat a. This model is now applied to the densities of liquid D2O in the tem perature range -20 to + 100 degrees C. It is found that the available experimental data can be fit to the reported five-decimal-point precis ion. As in the case of H2O, the output parameters indicate the existen ce of two general types of bonding characteristics in the liquid, a bu lky form similar to that in ice-Ih and a dense form such as that found in ice-II. Independent support for the model is obtained from the tem perature-differential X-ray scattering data of Bosio et al, on D2O.