12C0

12C0 is a notation whose meaning depends on the field in which it appears. In mathematics and related areas, 12C0 is typically understood as the binomial coefficient C(12, 0), read as “twelve choose zero.” The binomial coefficient is defined by C(n, k) = n! / (k!(n − k)!). For k = 0 this evaluates to 1, so 12C0 = 1. This value reflects the fact that there is exactly one way to select no elements from a set: to choose nothing. The binomial coefficient appears in combinatorics, probability, algebra, and in the expansion of (x + y)^n.

In chemistry and nuclear science, 12C denotes carbon-12, the stable isotope of carbon with mass number 12 (six protons and six neutrons). Isotope notation commonly presents the mass number as a superscript and the element symbol; the trailing zero in 12C0 is not standard notation. The charge state of an ion is typically indicated separately (e.g., 12C^+), and neutral atoms are written without an explicit charge. Therefore, 12C0 is generally regarded as nonstandard or context-dependent rather than a universal symbol.

Outside mathematics and chemical notation, the string 12C0 may occur as a code, label, or identifier in datasets, software, or documentation, where its meaning is defined ad hoc by the creator.