A química orgânica na consolidação dos conceitos de átomo e molécula Organic chemistry in the consolidation of the concepts of atom and molecule

• Published in: Química nova Vol. 32; no. 2; pp. 543 - 553
• Main Authors: Tânia de Oliveira Camel, Carlos B. G. Koehler, Carlos A. L. Filgueiras
• Format: Journal Article
• Language: English
• Published: Sociedade Brasileira de Química 01-01-2009
• Subjects: atoms and molecules; history of valence; molecular structure
• ISSN: 0100-4042; 1678-7064
• DOI: 10.1590/S0100-40422009000200045

The present work discusses the appearance of the concepts of valence and molecular structure, and describes the appropriation and evolution of the concept of molecule in the period following the publication of Avogadro's Hypothesis. The point of reference is the development of what became known as Organic Chemistry, which encompassed Pharmacy, Physiological Chemistry, Animal and Plant Chemistry, Chemistry of Dyestuffs, Agricultural Chemistry, and the fledgling Organic Synthesis industry in the early 19th century. The theories formulated in these areas and the quest for accurate atomic weights led to those concepts of valence and molecular structure and to a precise differentiation between atom and molecule.