Chemistry Work of Josef Loschmidt

 

Famous chemistry firsts1:
 
1.

The first correct cyclic structure of benzene and of many aromatic chemicals, 121 in all 2.

2.

The first representation of the allyl moiety.

3.

The first representation of the vinyl moiety and of many others.

4.

The first representation of cyclopropane, 21 years before it was made by Freund.

5.

The first picture book of molecules, containing graphic display with atomic domains, rather than abstract bond lines.

6.

The first double- and triple-bond marks (within the overlaps).

7.

The first realistic displays of atomic sizes and bond distances (largest overlap with triple bonds).

8.

The first set of diagrams with correct C=12, N=14, O=16 formulas.

9.

The first textbook use of atomic-group symbols.

10.

The first use of valence prime marks on these and atomic symbols ("Valenz" was introduced by Wichelhaus in 1868, 7 years later).

11.

The first line-formula notations ("rational formulas").

12.

The first revelation of hexavalent and tetravalent sulfur.

 
 
1

 
Wiswesser, W.J.: J. J. Loschmidt (1821-1895) A forgotten Genius. Aldrichimica Acta 22: 17-18, 1989

 
2

 
This point is somewhat of an overstatement. Loschmidt was the first to consider a monocyclic six carbon ring, but he did not know what to do with the double bonds.