C15H25

C15H25 is a molecular formula that denotes a compound composed of 15 carbon atoms and 25 hydrogen atoms. It can be used to describe neutral molecules, radicals, or ions that share this exact elemental composition.

In the context of hydrocarbons consisting only of carbon and hydrogen, the hydrogen count for a given number of carbons follows strict rules for degree of unsaturation. Using the standard formula for unsaturation, a neutral hydrocarbon with 15 carbons would have hydrogens in a range that yields an integer degree of unsaturation. The formula C15H25 would imply a non-integer degree of unsaturation (3.5) if interpreted as a neutral hydrocarbon with no heteroatoms, which is not possible for such species. Therefore, no stable neutral hydrocarbon with the exact composition C15H25 is known. If the molecule carries a charge, or includes heteroatoms that affect valence, the composition could still be realized.

Consequently, the formula C15H25 may be encountered in several contexts: as a radical (for example, C15H25•), as a charged species (C15H25+ or C15H25−), or as a tentative empirical formula for a compound containing other elements such as oxygen or sulfur. In these cases, the exact structure cannot be determined from the formula alone without additional information about bonding, charge, or elemental composition.

Related carbon counts often discussed in tandem include C15H24, C15H26, C15H28, and C15H30, which reflect varying degrees of unsaturation in carbon frameworks of similar size.