U

uncertainty principle unimolecular process
unit cell unsaturated




uncertainty principle

The idea that a theoretical limit exists on the accuracy with which the product of the position and momentum of a particle can be determined.


unimolecular process

An elementary step in a reaction mechanism; formally no species collide in such a step, but in actuality such processes usually involve a collision with a species that does not react.


unit cell

The smallest fragment of the structure of a solid that by repetition can generate the entire structure.


unsaturated

Describing 1) a solution that contains less than the maximum possible equilibrium concentration of a solute, or 2) an organic compound containing double or triple bonds.



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