Carbon–hydrogen bond C−H bond is generally regarded as being non-polar. In structural formulas of molecules, the hydrogen atoms are often omitted. Compound classes consisting solely of C–H bonds and C–C bonds are alkanes, alkenes, alkynes, and aromatic hydrocarbons. Collectively they are known as hydrocarbons. In October 2016, astronomers reported that the very basic chemical ingredients of life—the carbon-hydrogen molecule (CH, or methylidyne radical), the carbon-hydrogen positive ion (CH+) and the carbon ion (C+)—are the result, in large part, of ultraviolet light from stars, rather than in other ways, such as the result of turbulent events related to supernovae and young stars, as
Chemical formula a different connectivity from other molecules that can be formed using the same atoms in the same proportions (isomers). The formula (CH)CH implies a central carbon atom connected to one hydrogen atom and three CH groups. The same number of atoms of each element (10 hydrogens and 4 carbons, or CH) may be used to make a straight chain molecule, "n"-butane: CHCHCHCH. In any given chemical compound, the elements always combine in the same proportion with each other. This is the law of constant composition. The law of constant composition says that, in any particular chemical compound, all samples of