Specific rotation

Specific rotation (pronounced: speh-si-fik roh-tay-shun) is a property of chiral substances that quantifies the degree to which the substance can rotate the plane of polarized light. It is a standard physical constant for the identification of pure, chiral substances.

Etymology

The term "specific rotation" is derived from the specific nature of the rotation, which is unique to each chiral substance, and the action of rotation that the substance imparts on polarized light.

Definition

Specific rotation is defined as the observed rotation in degrees when plane-polarized light passes through a solution of one gram of the substance in 1 mL of a specified solvent at a specified temperature and wavelength, usually sodium D-line light (589 nm) at 20°C. The specific rotation is represented by the symbol [α].

Calculation

The specific rotation is calculated using the formula:

[α] = α / (l * c)

where:

α is the observed rotation in degrees,
l is the path length in decimeters (dm), and
c is the concentration in grams per milliliter (g/mL).

Related terms

Optical rotation: The rotation of the plane of polarized light by a chiral substance.
Chirality (chemistry): The property of a molecule that makes it non-superimposable on its mirror image.
Polarized light: Light waves in which the vibrations occur in a single plane.

External links

Medical encyclopedia article on Specific rotation
Wikipedia's article - Specific rotation

This WikiMD article is a stub. You can help make it a full article.

Languages: - East Asian 中文, 日本, 한국어, South Asian हिन्दी, Urdu, বাংলা, తెలుగు, தமிழ், ಕನ್ನಡ,
Southeast Asian Indonesian, Vietnamese, Thai, မြန်မာဘာသာ, European español, Deutsch, français, русский, português do Brasil, Italian, polski

Specific rotation