The above is a copyrighted picture reproduced here by permission. © 2009 by Jochen Wilke.
In Silber auf eisernem Dreifuss in flammendem Kohlenbecken ein
natürlicher Siedekolben,
in den vier Schildesecken begleitet von je
einer goldenbesamten roten Rose.
Auf dem Helm mit rot-silbernen Decken,
3 golden-besamte rote Rosen an grünen Blätterstengeln.
Hofmann is commonly credited for being the first chemistry professor to use (primitive) molecular models in public lectures. The color coding he introduced for that purpose became the basis for the scheme used in most modern sets, which was tentatively standardized by the Institute of Physics in 1947: carbon=black, hydrogen=white, oxygen=red, halogens=greenish, nitrogen=blue, sulfur=yellow, phosphorus=purple...
Institute of Physics, "The standardization of crystal structure models" Journal of Scientific Instruments, Vol. 24, 9 pp. 249-250 (1947).
The British Museum has several molecular models that had been used by earlier chemists, including John Dalton (1766-1844). The use of polyhedral models predates the theoretical framework which made them legitimate for chemistry: Johannes Kepler (1571-1630) used them to speculate about the microscopic structure of crystals as early as 1611...
Wikipedia | Hofmann elimination | Hofmann rearrangement | Hofmann-Löffler reaction | Bibliography on Molecular Models (NBS, 1960)
