Refraktaarsust

Refraktaarsust, often translated as refractivity, is a physical property of a material that describes how much its path of light is bent when entering the material from a vacuum. It is closely related to the refractive index, which is a dimensionless quantity that expresses the ratio of the speed of light in vacuum to the speed of light in the material. Refractivity is essentially the inverse of the refractive index squared, multiplied by a factor related to the molar mass and density of the substance.

The concept of refractivity is useful in chemistry and physics for characterizing substances. It is an additive property, meaning that the refractivity of a molecule can be approximated by summing the refractivities of its constituent atoms or functional groups. This allows chemists to estimate the refractive index of a compound based on its structure, which can be helpful for identification and purity assessment.

Refraktaarsust is typically expressed in units of volume per mass, such as cubic meters per kilogram. It is a temperature-dependent property, and values are usually reported at a specific temperature, often 20 degrees Celsius. The molar refractivity, which is the refractivity multiplied by the molar mass, is a more commonly used quantity as it is less dependent on the molecular weight. This property finds applications in various fields, including optical engineering, materials science, and analytical chemistry.