Configurational

Configurational is an adjective derived from configuration, referring to the arrangement or organization of components within a system and the ways such arrangements can be described, constrained, or changed. The term is used across disciplines, including chemistry, physics, materials science, and statistics, to distinguish static arrangements (configurations) from dynamic or kinetic processes.

In chemistry, configurational isomers are stereoisomers that cannot interconvert without breaking bonds, as opposed to conformational isomers that arise from rotation about single bonds. Examples include geometric isomers of alkenes, such as cis- and trans- (E/Z) isomers, and enantiomers. Interconversion of configurational isomers typically requires chemical reactions; conformers interconvert by rotation at ambient temperatures.

In thermodynamics and statistical mechanics, configurational entropy refers to the part of a system's entropy associated with the number of distinct arrangements of its constituents in space, independent of vibrational or translational motion. The concept extends to configurational space, the set of all possible configurations, and to models such as lattice gases and glass-forming systems where configurational degrees of freedom drive behavior.

In materials science and crystallography, configurational aspects describe disorder or ordering in solid solutions, alloy phases, and crystal defects. Configurational averaging and occupancy models are used to compute properties from the distribution of species among lattice sites, while configurational disorder can influence physical properties such as conductivity, magnetic behavior, and phase stability.