For other uses, see Curie (disambiguation).

The curie (symbol Ci) is a former unit of radioactivity, defined as:

$1\; Ci\; =\; 3.7\; \backslash times\; 10^\{10\}\; \backslash$ decays per second.

This is roughly the activity of 1 gram of the radium isotope ²²⁶Ra, a substance studied by the pioneers of radiology, Marie and Pierre Curie (for whom the unit is named). The curie has since been replaced by an SI derived unit, the becquerel (Bq), which equates to one decay per second. Therefore:

$1\; Ci\; =\; 37\; GBq\; \backslash$   , and

$1\; Bq\; =\; 2.7\backslash overline\{027\}\; \backslash times\; 10^\{-11\}\; Ci$ (the overline denotes a repeating decimal).

Units of radioactivity | Radioactivity

Curie (Einheit) | Curio (unidad) | Curie (unité) | Curie | קירי | Curie | Curie (eenheid) | キュリー | Kiur (jednostka miary) | Curie | Кюри (единица измерения) | Curie