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Why does the World need a Common Language for Scientists?

Juergen Stohner, Professor, ZHAW Zurich University for Applied Sciences, ICBT Institute for Chemistry & Biotechnology, Switzerland Ron D. Weir, Emeritus Professor, Department of Chemistry & Chemical Engineering, Royal Military College of Canada

1What is the role of IUPAC in providing International Standards and a Common Language for Scientists?

When the International Union of Pure and Applied Chemistry (IUPAC) was founded in 1919, international science was in its infancy.  Modern instantaneous communications as we know them had not been born but a number of scientists foresaw the need for an international organisation with a focus on chemical sciences to serve as a catalyst to promote standards and to facilitate clear unambiguous communications throughout the world in the rapidly growing discipline. In the year 2019 of the 100th anniversary of IUPAC, the early founders of the organisation could not have foreseen the explosion of knowledge, the extent of scientific and technological advances.  Communication networks now span the world to provide instantaneous links virtually everywhere.  This dramatic development has enormous benefits as well as some challenges.  Fortunately the founders of IUPAC 100 years ago did understand the serious ramifications of not having clear unambiguous communication in science and engineering.

IUPAC is the world authority on chemical nomenclature and terminology, including the naming of new elements in the periodic table [1]; on standardized methods for measurement; on relative atomic masses (“atomic weights”), and many other critically-evaluated data within the broad spectrum that embraces the chemical sciences.

IUPAC is also involved in the revision of the new SI (International System of Units) (see IUPAC project 2013-048-1-100) which has consequences for the chemical community via the redefinition of the Avogadro constant. A new definition of the mole was recently published in IUPAC journal Pure and Applied Chemistry, January 2018 issue, page 175.

2Why Do We Need a Common Language in Chemical Sciences? Example 1: The Mars Climate Orbiter

There are several reasons for setting international standards by IUPAC that are relevant to society. These are (i) saving resources, (ii) saving money, and (iii) saving lives. Let us consider a few examples.

The United States National Aeronautics and Space Administration (NASA) Mars Climate Orbiter was lost 1999 due to an incorrect conversion between metric and English (USA) units. While, the financial loss amounted to about $125 million US dollars, a price cannot be placed on the loss of scientific data and associated work. It was fortunate that human lives were not involved. For more information see information released by NASA [2] at time and articles written by WIRED magazine [3] shortly after the accident.

Source: NASA. Artist’s rendering of the Mars Climate Orbiter.

3Example 2: The Laufenburg Bridge

Construction of the Laufenburg Bridge over the Rhine between Switzerland and Germany in 2003.  Germany used the North Sea level as its standard reference while Switzerland used the Mediterranean Sea as its reference level.   The difference in levels is 27 cm.  To make matters worse, when the adjustment was made, the signs were applied incorrectly. The total difference applied to the two ends of the bridge was 54 cm that resulted in a costly error.  For more information see What Happens To A Bridge When One Side Uses Mediterranean Sea Level And Another The North Sea? | Science 2.0 [4].


4Example 3: Toxicology and health care

In a patient, blood glucose levels were read on the glucose meter (made in the USA) as 42 mmol∙L-1 (note that litre, symbol L, is a non-SI unit, but accepted for use with the SI) that was assumed by staff as 42 mg∙dL-1. The former value, however, is equivalent to 758 mg∙dL-1! The drastic ramification was a diagnosis of hypoglycemia rather than hyperglycemia nearly costing the patient his life.  The problem arose because the glucose meter used did not conform to IUPAC international standards distinguishing between amount concentration (symbol c, SI unit mol∙m-3) and mass concentration (symbol g, SI unit kg∙m-3)    The USA is one of a few hold-out countries against adopting the metric or SI system even in medical equipment.  The International Committee of Medical Journal Editors has demanded that all measurements associated with medicine are to be reported in metric units and temperatures in degrees Celcius. This example emphasizes the importance of the adoption of an internationally agreed-upon standard scientific language around the world. For details see the editorial “S.I. for Dummies” printed in the Journal of Medical Toxicology 3(3) 87-88 (2007) by Dr. Tomaszewski (doi.org/10.1007/BF03160915) [5]. 

5About Incorrect Writing of Units

Units can be combined with prefixes which are abbreviations to certain multiples of the power of 10 (so called decimal multiples). Rules exist on how to write units combined with prefixes, for example 1 kg is equal to 103 g signifying that “kilo” stands for 1000 or 103.

However, whether or not a prefix is written with small or capital letters is not a matter of taste, for example writing mW (milliwatt or 10-3 Watt) is very different from MW (megawatt, 106 Watt), namely by 9 orders of magnitude.

A nice example can be found on some signs for speed limits where speed is given in Km/H instead of km/h.  An amusing misguided example appears sometimes in restaurants where wine prices are shown as local currency per ML instead of mL. The former would be an incredible bargain!

Source: https://justfinding.blogspot.com/2013/08/august-11-border-crossing.html

Prefixes can even lead to ambiguities: ppt is often used to denote parts per thousand or 10-3 as an alternative for per mille, symbol ‰, but ppt is also frequently interpreted as parts per trillion or 10-12.

In a few cases, prefixes do have different meaning in different countries. For example billion in the US means 109 whereas a billion in Europe and other parts of the world means 1012. This is why IUPAC also cares about the proper use of units and in some cases deprecates the use of certain symbols or names to avoid ambiguities and misinterpretations.

6How are the standards developed and achieved to ensure global consensus with scientific bodies and the general public?

Experts in the various fields of science throughout the world work together within the IUPAC eight Divisions and three Commissions to develop standards and make recommendations. Global consensus is reached through the participation by international representatives serving on the IUPAC Divisions and Commissions; representatives from the IUPAC National Adhering Organisations (including national chemical societies); representatives from other scientific organizations serving on IUPAC to include: the International Union of Crystallography, the International Union of Nutritional Science, the International Union of Pure and Applied Physics, the International Union of Biochemistry and Molecular Biology, the International Bureau of Weights and Measures, International Union of Pharmacology; IUPAC representatives on the International Organisation for Standardisation (ISO), the International Bureau of Weights and Measures, the International Council for Science, and finally through a public review period of several months.

Following this extensive consultation, approved feedback, and approved scientific reviews, it is assumed that each respective community supports the consensus.

The general public is involved indirectly through National Societies and from the public review of Provisional Recommendations during which time the public can submit comments and suggestions. These are augmented via National newspaper articles that often highlight relevant IUPAC work such as the discovery of new elements and how they are named. A case in point is the recent announcement by IUPAC of the discovery and naming of the four new elements in the periodic table.

7What is the usual timeline from start to finish?

After extensive consultation as noted above, an IUPAC Division approves the final text of the proposed standard or recommendation and the manuscript is sent to the IUPAC Interdivisional Committee on Terminology, Nomenclature and Symbols (ICTNS) for further review, internal and external to IUPAC.  In the case of a formal Recommendation, the manuscript is posted publically for five months to invite and encourage comments from the general public.  In parallel, the manuscript is sent to as many as twenty-five additional expert reviewers. The time elapsed to publication in the IUPAC journal Pure and Applied Chemistry (PAC) is about twenty-four months.

In the case of a Technical Report, which is not a policy document of IUPAC but rather a report on the subject of a specific study, such as critical assessments of methods and techniques, the total time elapsed between Division approval and ICTNS review is about fifteen months. For any changes to the International System of Units (S.I.) itself, the International Bureau of Weights and Measures (BIPM) and its hierarchical structure outside of IUPAC may take several years to achieve consensus. A current example is the ongoing discussion to realign the definition of the mole.

8How are the Standards and Recommendations used and valued?

The guidelines for good practice with respect to terminology, units, and symbols are embodied in the IUPAC Green Book as well as to nomenclature along with other IUPAC Colour Books.

The IUPAC Colour Books are the world’s authoritative resource for chemical nomenclature, terminology, symbols, and units. The list of Colour Books is shown below.  In general, the vast majority of scientists and most scientific journals adhere to the IUPAC Recommendations for international practice.  There are some exceptions usually associated with individuals who cannot adjust to change and some countries whose political history appears to shun international consensus. The potential impact of not following the standard and recommendations is noted above. In terms of value, a number of peer-reviewed journals will only accept papers that follow the IUPAC policy.  In addition, the UNESCO and EU Customs Union recognise the IUPAC system as their official policy.

9How often are the Standards and Recommendations updated?

There is no single simple answer. Whenever an IUPAC Division or Commission believes that an update is required to a Recommendation or a Technical Report, then the changes are made via the process described above.  As an example, the atomic masses of the elements are updated every one or two years. However, the frequency of the discovery of a new element is rare, but when a discovery is verified, such as announced at the end of 2015, the update is put in place.  See IUPAC | International Union of Pure and Applied Chemistry Periodic Table of Elements. For the Colour Books, because sophisticated work is involved, the updates may be done every five or six years or longer.



All the work of IUPAC is done, almost entirely on a volunteer basis, by more than a thousand scientists from around the world, who serve on IUPAC Divisions, Commissions, Standing Committees, and Task Groups. This has not changed much in the past 100 years. What is changing however is the extent of these standards and recommendations and the recognition that they now need to also allow for clear and unambiguous communication between machines. For an example of how IUPAC has been thinking ahead, and providing tool for machines to communicate, see the first story in this series “What on Earth is InChI?” (see https://iupac.org/100/stories/what-on-earth-is-inchi/).


* An earlier version of this document was first prepared as an introduction to the IUPAC Standards Online database developed by DeGruyter and published in Chemistry International in April 2017 (CI 39(2), pp. 34-35; https://doi.org/10.1515/ci-2017-0227).


  1. IUPAC Periodic Table of the Elements - https://iupac.org/what-we-do/periodic-table-of-elements/
  2. Isbell, D., Hardin, M., Underwood, J. 1999. Mars climate orbiter team finds likely cause of loss. NASA, Release 99-113. - https://mars.nasa.gov/msp98/news/mco990930.html
  3. Grossman, L. 2010. Nov. 10, 1999: metric math mistake muffed mars meteorology mission. Wired. - https://www.wired.com/2010/11/1110mars-climate-observer-report/
  4. News Staff. 2013. What happens to a bridge when one side uses Mediterranean Sea level and another the North Sea? Science 2.0 - https://www.science20.com/news_articles/what_happens_bridge_when_one_side_uses_mediterranean_sea_level_and_another_north_sea-121600
  5. Tomaszewski, C. 2007. S. I. for dummies. J Medical Toxicology, 3:87-88. - https://doi.org/10.1007/BF03160915


Stohner, J., Weir, R. (2 Apr 2018) "Why does the World need a Common Language for Scientists?" IUPAC 100 Stories. Retrieved from https://iupac.org/100/stories/a-common-language-for-scientists/. (Accessed: day month year)

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