Toward a definition of valence as a quantity (IUPAC Technical Report)
Pavel Karen, Lidia Armelao, Ian S. Butler, Vladislav Tomišić and Makoto Yamashita
Pure and Applied Chemistry 20225,
Vol. 97, no. 2, pp. 149-187
https://doi.org/10.1515/pac-2023-0402
Valence has a rich history in chemistry, as a bonding concept, in terms of quantitative context, and as a true quantity. In the latter, a survey preceding this project revealed differing perceptions of valence values and helped formulate candidate definitions. This IUPAC task group evaluated nine quantities behind eight alternative definitions on 39 chemical entities of 48 bonding formulas, each giving a set of meaningful values with mutual relationships. Given the reflection principle of IUPAC normative work, 15 comparative examples with high variation of these alternative valences for an element were selected, and chemistry articles in English searched for valence-termed quantities of the compared compounds to imply the definition behind the stated valence value, the frequency of such use, and the chemistry field. Summarized preferences for the alternative definitions show two main areas of use. Organic and physical chemists count valence as a number of two-electron bonds at the atom. Inorganic chemists working with semi-metallic and metallic elements use n-valent as an adjective for oxidation state. The diverse yet infrequent use cannot be covered by a single definition of the valence quantity. Clarity in articles that use valence as a quantity is essential and achievable by stating the intended context.
©2025 by Walter de Gruyter Berlin/Boston
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Articles in the same Issue
- Masthead - Full issue pdf
- Vice President’s Column
- Reimagining the Scientific Horizons of IUPAC
- Features
- Chemistry’s Role in Malaysia Sustainable Development Progress
- Reusing Chemical Data Across Disciplines: Initiatives and Common Challenges
- IUPAC reflectivity principle for normative work—the case of valence as a quantity
- IUPAC Wire
- Awardees of the IUPAC 2025 Distinguished Women in Chemistry or Chemical Engineering
- Paolo Franzosini Prize and Christo Balarew Award 2024
- Graham Cooks and Anna Regoutz win the 2025 Awards in Analytical Chemistry
- Peter Mahaffy to Receive 2025 Pimentel Award for Outstanding Contributions to Chemistry Education
- Zafra Lerman to Receive Cardozo’s 24th Annual International Advocate for Peace Award
- CIAAW Student Observer Grant 2025
- USNC/IUPAC Announces the 2025 Young Observers and IYCN Delegates
- The Muscat Global Knowledge Dialogue and the 3rd ISC General Assembly: IUPAC’s Role in Shaping Global Science Policy
- In Memoriam
- Project Place
- Setting Standards for Wearable Biochemical Measurement Devices: Defining Nomenclature and Guidelines
- Promoting Chemistry Applied to World Needs
- The isotopic composition of VPDB
- IUPAC Provisional Recommendations
- Radical Copolymerization Reactivity
- Making an imPACt
- Toward a definition of valence as a quantity (IUPAC Technical Report)
- Diffusion in nanoporous materials with special consideration of the measurement of determining parameters (IUPAC Technical Report)
- Thermoplastic Starch with Maltodextrin: Preparation, Morphology, Rheology, and Mechanical Properties
- Glossary of terms for mass and volume in analytical chemistry (IUPAC Recommendations 2024)
- Special CTI
- Conference Call
- Medicinal Chemistry and Drug Discovery & Development India
- Solubility Phenomena and Related Equilibrium Processes
- The Historic Gathering of IUPAC Presidents at the 10th International Conference of Green Chemistry
- Chemistry, a Lever for Sustainable Development of African Countries
- Where 2B & Y
- Space Exploration and Research
- Mark Your Calendar
Articles in the same Issue
- Masthead - Full issue pdf
- Vice President’s Column
- Reimagining the Scientific Horizons of IUPAC
- Features
- Chemistry’s Role in Malaysia Sustainable Development Progress
- Reusing Chemical Data Across Disciplines: Initiatives and Common Challenges
- IUPAC reflectivity principle for normative work—the case of valence as a quantity
- IUPAC Wire
- Awardees of the IUPAC 2025 Distinguished Women in Chemistry or Chemical Engineering
- Paolo Franzosini Prize and Christo Balarew Award 2024
- Graham Cooks and Anna Regoutz win the 2025 Awards in Analytical Chemistry
- Peter Mahaffy to Receive 2025 Pimentel Award for Outstanding Contributions to Chemistry Education
- Zafra Lerman to Receive Cardozo’s 24th Annual International Advocate for Peace Award
- CIAAW Student Observer Grant 2025
- USNC/IUPAC Announces the 2025 Young Observers and IYCN Delegates
- The Muscat Global Knowledge Dialogue and the 3rd ISC General Assembly: IUPAC’s Role in Shaping Global Science Policy
- In Memoriam
- Project Place
- Setting Standards for Wearable Biochemical Measurement Devices: Defining Nomenclature and Guidelines
- Promoting Chemistry Applied to World Needs
- The isotopic composition of VPDB
- IUPAC Provisional Recommendations
- Radical Copolymerization Reactivity
- Making an imPACt
- Toward a definition of valence as a quantity (IUPAC Technical Report)
- Diffusion in nanoporous materials with special consideration of the measurement of determining parameters (IUPAC Technical Report)
- Thermoplastic Starch with Maltodextrin: Preparation, Morphology, Rheology, and Mechanical Properties
- Glossary of terms for mass and volume in analytical chemistry (IUPAC Recommendations 2024)
- Special CTI
- Conference Call
- Medicinal Chemistry and Drug Discovery & Development India
- Solubility Phenomena and Related Equilibrium Processes
- The Historic Gathering of IUPAC Presidents at the 10th International Conference of Green Chemistry
- Chemistry, a Lever for Sustainable Development of African Countries
- Where 2B & Y
- Space Exploration and Research
- Mark Your Calendar
