virtual Chemistry 3D - Molecular Structure

Molecular Structure: Playground

If you are not sure what you are looking for, you can search the compound you are interested with on the ChemSpider website, and then paste its name in JSmol Search field. ChemSpider is a free chemical structure database providing fast text and structure search access to millions of structures. ChemSpider also exists as a free Android or iOS mobile app.

Select a molecule on the NCI, PubChem or RSCB servers, or among the selected examples.

Examine the geometry and check if its consistent with your knowledge.
You can also load your own coordinate file. Jmol accepts several formats (xyz, pdb, mol,...).

More information about the nomenclature of organic chemistry on Wikipedia and IUPAC. Nomenclature of inorganic chemistry on Wikipedia.