Teaching hydrogen bridges: it is not FON anymore!
Author:
Lamoureux Guy V.12, Chaves-Carballo Katherine12
Affiliation:
1. 27915 Escuela de Química, Universidad de Costa Rica , San Pedro , San José , Costa Rica 2. Centro de Investigaciones en Productos Naturales (CIPRONA) , 27915 Universidad de Costa Rica , San Pedro , San José , Costa Rica
Abstract
Abstract
Teaching hydrogen bridges (H-bridges) in introductory chemistry courses is either oversimplified or dogmatically taught; the heuristic that ‘only fluorine, oxygen and nitrogen (FON) form H-bridges’ is commonly used, for example. This rule limits choices, does not match reality, and does not clarify the difference between H-bridge donors (HBD) and H-bridge acceptors (HBA) nor intermolecular versus intramolecular cases. Hydrogen fluoride is a significant HBD but a poor HBA. Oxygen is not always an HBD or HBA. Ammonia is a significant HBA but a poor HBD. There are many examples of H-bridges that do not contain these three elements. All examples of H-bridges should be shown in a way to provide symbolic and molecular structures. Is it necessary to ‘explain’ H-bridges in introductory classes? We conclude not, but it might be necessary to increase the total amount of time to present the material so that students do not rely on superficial rules.
Funder
The Centro de Investigaciones en Productos Naturales and Escuela de Química, Universidad de Costa Rica
Publisher
Walter de Gruyter GmbH
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