Simplified molecular-input line-entry system - Wikipedia
https://en.wikipedia.org/wiki/Simplified_molecular-input_line-entry_systemAtoms are represented by the standard abbreviation of the chemical elements, in square brackets, such as [Au] for gold. Brackets may be omitted in the common case of atoms which: are in the "organic subset" of B, C, N, O, P, S, F, Cl, Br, or I, and have no formal charge, and
Oxygen | O2 - PubChem
https://pubchem.ncbi.nlm.nih.gov/compound/oxygenOxygen is an element displayed by the symbol O, and atomic number 8. It is an essential element for human survival. Decreased oxygen levels may be treated with medical oxygen therapy. Treatment with oxygen serves to increase blood oxygen levels and also exerts a secondary effect of decreasing blood flow resistance in the diseased lung, leading to decreased cardiovascular …
Phenyl group - Wikipedia
https://en.wikipedia.org/wiki/Phenyl_groupIn organic chemistry, the phenyl group, or phenyl ring, is a cyclic group of atoms with the formula C 6 H 5.Phenyl groups are closely related to benzene and can be viewed as a benzene ring, minus a hydrogen, which may be replaced by some other element or compound to serve as a functional group.Phenyl groups have six carbon atoms bonded together in a hexagonal planar ring, five of …