Which characteristic distinguishes chiral compounds?

Chiral compounds are characterized by having no plane of symmetry, which means that they cannot be superimposed on their mirror image. This lack of symmetry is what allows for the existence of two different forms, or enantiomers, of a chiral molecule. Each enantiomer will have distinct spatial arrangements of atoms, leading to different physical and chemical properties in certain environments, such as in biological systems where chirality can have significant implications.

In contrast, a plane of symmetry would indicate that a molecule is superimposable on its mirror image, thus making it achiral. This is critical for understanding chiral compounds as it establishes the fundamental difference that allows chirality to exist. The other options do not accurately reflect the defining features of chiral compounds. For instance, chiral compounds are defined by their ability to form two distinct enantiomers, which means that they do exist in multiple forms. Additionally, they do not always exist in equal concentrations of enantiomers; this can vary depending on the conditions and reactions they undergo. Understanding these characteristics is essential for deeper insight into molecular stereochemistry and its relevance in various chemical and biological processes.