Solubilitat

Solubilitat is the capacity of a solute to dissolve in a solvent to form a homogeneous solution. It is defined as the maximum amount of solute that can dissolve at a given temperature in a specified amount of solvent, producing a saturated solution. Solubilitat depends on the chemical nature of both solute and solvent and on external conditions such as temperature and, for gases, pressure. It is distinct from the rate at which dissolution occurs.

Solubility is commonly expressed in several units, including grams of solute per 100 grams of solvent, mole fraction, molarity, or molality. For sparingly soluble compounds, solubitat is often described using the solubility product constant, Ksp, which describes the equilibrium between solid and dissolved ions.

Temperature effects are characteristic: for most solid solutes in water, solubilitat increases with temperature; for many gases, solubility decreases as temperature rises, while gas solubility generally increases with higher pressure (Henry’s law). Solubitat can also be influenced by pH and complexation: ionization, formation of soluble complexes, and the presence of common ions can alter apparent solubility. Intermolecular interactions, lattice energy of the solid, and solvent structure also play roles.

Practical relevance includes pharmaceutical formulation, environmental fate of chemicals, and materials science. Techniques to modify solubitat include heating, using different solvents or cosolvents, salt formation, pH adjustment, forming inclusion complexes, or employing solid dispersions. Accurate solubitat data are essential for predicting dissolution behavior, design of experiments, and the interpretation of chemical processes.