SSMILES is an extremely simplified subset of SMILES used for expressing the molecular graph of "normal" organic chemicals, i.e., neutral molecules with atoms at their normal organic valences. In such cases there is no need for the brackets, charges, aromatic specifications, atom mapping, etc. used in the full SMILES language. If you only need to operate on such organic structures, simple forms of the six SMILES rules are pretty much all you need to know.
|C||methane||Hydrogens fill normal valence.|
|CCO||ethanol||A single bond is assumed to join adjacent atoms unless otherwise specified.|
|C=O||formaldehyde||An "equals" sign represents a double bond.|
|C#N||hydrogen cyanide||A "pounds" sign represents a triple bond.|
|CC(=O)O||acetic acid||Parentheses are used to indicate branching.|
|CC(C)(C)C||neopentane||Branches may be stacked.|
|C1CCCCC1||cyclohexane||Bonds can also be represented by pairs of matching digits, e.g., ring closures.|
|N1=CC=CC=C1||pyridine||Aromatic compounds are written as Kekule structures.|
|S2C=CC=C2||thiophene||Any ring closure digit may be used.|
|CC(=O)O.CCO||acetic acid and ethanol||A period is a "non-bond"|
|CC(=O)O.CCO>>CC(=O)OCC.O||esterification of acetic acid and ethanol to ethyl acetate and water||Two >'s are required but components are optional.|
The SSMILES subset of SMILES is formalized to provide a truly simple chemical nomeclature, i.e., one that can be learned "on the spot" each time it is needed. However, it is not a comprehensive chemical nomenclature: one cannot specify inorganic elements, disconnections, formal charges, unusual valences, isotopic and chiral specifications, nor reaction mapping. See the description of the full SMILES language for more information.