Information about vaporization processes and the thermodynamic properties of oxide melts is of importance for various fields of high-temperature technologies. The available data on the thermodynamic properties of binary borate, silicate, germanate, and phosphate melts studied by mass spectrometry have been compared in the framework of the acid–base concept. The reliability of experimental data is analyzed on the basis of a comparison between the results obtained by different mass spectrometric techniques and those determined by various methods of high-temperature chemistry, such as the electromotive force (emf) technique, high-temperature dissolution calorimetry, and the method of exchange equilibria in slags. Deviations of the chemical potentials for P2O5, B2O3, SiO2, and GeO2 from the ideal behavior as a function of the oxide modifier content in series of binary systems reflect the diversity of processes (dissociation, association, and polymerization) accompanying the vaporization of their components.