CnHmNxOy

CnHmNxOy is a generalized molecular formula used in chemistry to denote a class of organic compounds containing carbon, hydrogen, nitrogen, and oxygen. In this convention, n, m, x, and y are nonnegative integers representing the numbers of C, H, N, and O atoms in the molecule, respectively. Because only a composition is specified, CnHmNxOy does not identify a single compound but a family of possible structures that share this elemental makeup.

The notation is commonly used in discussions of empirical formulas, in mass-spectrometry interpretation, and in computational generation of candidate structures when the exact arrangement of atoms is unknown. It also appears in polymer science and combinatorial chemistry as a way to represent units or motifs that include C, H, N, and O.

Important limitations: the same counts can correspond to multiple distinct molecules; the empirical formula CnHmNxOy can often be reduced by a common factor. In real chemistry, other elements such as sulfur, phosphorus, or halogens may be present, which would extend the notation beyond the four-element scheme.

Example: acetamide has the empirical formula C2H5NO, corresponding to n=2, m=5, x=1, y=1. This illustrates how CnHmNxOy can summarize composition without specifying connectivity or stereochemistry. The notation is especially useful for describing unknown or variable compositions in theoretical analyses and database searches.