Volatility (chemistry) Volatility (chemistry) In chemistry and physics, volatility is quantified by the tendency of a substance to vaporize. Volatility is directly related to a substance's vapor pressure. At a given temperature, a substance with higher vapor pressure vaporizes more readily than a substance with a lower vapor pressure. The term is primarily written to be applied to liquids; however, it may be used to describe the process of sublimation which is associated with solid substances, such as dry ice (solid carbon dioxide) and osmium tetroxide (OsO), which can change directly from the solid state to a vapor, without becoming liquid. The
Solidus (chemistry) Solidus (chemistry) In chemistry, materials science, and physics, the solidus is the locus of temperatures (a curve on a phase diagram) below which a given substance is completely solid (crystallized). The solidus is applied, among other materials, to metal alloys, ceramics, and natural rocks and minerals. The solidus quantifies the temperature at which melting of a substance "begins", but the substance is not necessarily melted "completely", i.e., the solidus is not necessarily a melting point. For this distinction, the solidus may be contrasted to the liquidus. The solidus is always less than or equal to the liquidus, but they need