This corresponds to the atoms being in the same chemical position in two identical molecules.
The first example combines two atoms that are in identical chemical positions and one lone unmapped atom.
Crum Brown made a similar distinction, cautioning that in his graphical formulae he did not "mean to indicate the physical, but merely the chemical position of the atoms" (Crum Brown, 1864, 232).
The results indicate that the exchange of the counter-ion Cl− of PTHT by a linear long chain with RSO−3 group is a general procedure to obtain PPV polymer at lower conversion temperature (ca. 110 °C) with significant increase in the emission efficiency, regardless of the chemical position and the number of sulfonate groups.
To overcome losses due to configurational interactions leading to enhanced radiationless relaxation rates, one might consider alternative linker chemistries that may affix the fluorophore in stringent chemical positions.
In summary, this study demonstrates that the linkage of different neuropeptides to squalene in various chemical positions allows the production of a library of nanoassemblies.
For example, the chemical global positioning system ChemGPS [30] utilizes PCA to create a 'navigation map' in drug-like space.
But she ultimately took a chemical engineering position at Exxon, choosing it over 11 other job offers she received upon graduation.
John M. Rost, the chairman of the North American Metal Packaging Alliance, an industry group, said that there was no evidence that the linings expose humans to significant amounts of the chemical, a position not shared by all scientists.
The chemical space position and important contributors were compared between selected drug molecules and organic compounds available in the literature.
If the chemical spill position was close to an exhaust, the contaminant concentration in the laboratory could be rather low.
