Kf

Kf is an abbreviation that appears in several scientific and technical disciplines. There is no single universal definition; its meaning depends on context, field, and convention.

In chemistry, Kf commonly denotes the formation or stability constant of a complex, for example a metal ion M binding to a ligand L to form ML. The equilibrium Kf is defined as [ML]/([M][L]). Higher Kf values indicate stronger complex formation, and when reported as log Kf, they enable comparison across systems and conditions.

In physiology, particularly renal physiology, Kf stands for the filtration coefficient. Kf equals the product of hydraulic permeability and functional surface area of the glomerular capillary bed, and has units of volume per time per pressure (for example ml·min−1·mmHg−1). It is a key parameter in the Starling forces governing glomerular filtration rate.

In chemical kinetics, kf is the standard symbol for a forward rate constant, while Kf is less common and may appear as a parameter in some older or field-specific models. Users should check field-specific definitions in any given text.

Because Kf is used differently in different domains, readers should interpret it from context and explicit definitions in the source material.