strukturformel

Strukturformel, or structural formula, is a representation used in chemistry to depict the arrangement of atoms within a molecule and the bonds that join them. It emphasizes connectivity and functional groups but does not necessarily depict exact three-dimensional geometry. Structural formulas are essential for communicating how a compound is put together, predicting reactivity, and planning syntheses.

There are several formats. A full structural formula, often drawn with element symbols and lines for bonds, shows every atom and bond. In condensed structural formulas, atoms are listed in sequence without drawing every bond. Line-angle (skeletal) formulas represent carbon skeletons as vertices and line ends, with bonds implied and heteroatoms shown at explicit positions. In aromatic compounds, Kekulé structures may be used to illustrate alternating bonds.

Hydrogen atoms bonded to carbon are frequently omitted, while heteroatoms (such as O, N, or halogens) are shown explicitly. Double and triple bonds are indicated by double or triple lines. To communicate stereochemistry, wedge and dash bonds indicate bonds oriented out of or into the plane, and more advanced notations may specify relative configurations.

Limitations include that a single structural formula cannot convey exact bond lengths or angles and may not uniquely determine the three-dimensional shape of a molecule, especially in flexible systems. For complete 3D information, models, crystallography data, or computational structures are used. Structural formulas are widely used in education, publication, and chemical communication to convey connectivity quickly and unambiguously.