Clathrates were studied by P. Pfeiffer in 1927 and in 1930, E. Hertel defined "molecular compounds" as substances decomposed into individual components following the mass action law in solution or gas state.
Os clatratos foron estudados por P. Pfeiffer en 1927, e en 1930 E. Hertel definiu os "compostos moleculares" como substancias descompostas en compoñentes individuais que seguían a lei de acción de masas en solución ou estado gasoso.