If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.


Chemical Bonding


February 26, 2021 | A version of this story appeared in Volume 99, Issue 7


Letters to the editor

Line between hydrogen and covalent bonds

We were very surprised to read the article “Line Blurs between Hydrogen and Covalent Bonds” in the Jan. 11, 2021, issue of C&EN (page 3), which implied that the changing nature of the hydrogen bond is a new finding. In 1999, Hans-Heinrich Limbach and coauthors published two papers on the experimental nuclear magnetic resonance spectra of FH:collidine as a function of temperature, which provided evidence of the changing nature of the hydrogen bond. We carried out equation-of-motion coupled-cluster singles and doubles calculations to obtain the coupling constants for a model system FH:pyridine as a function of the HF distance. The results of these calculations supported the experimental data and interpretation given by Limbach concerning the changing nature of the hydrogen bond. Since that time, we have published approximately 20 papers that further characterized the changing nature of the hydrogen bond from traditional to proton shared to ion pair in other systems. It is unfortunate that Limbach’s papers and ours were not quoted, since the “blur between hydrogen and covalent bonds” had been discussed in detail in the literature many times prior to the Jan. 11 Concentrate.

Janet E. Del Bene (Youngstown, Ohio), Ibon Alkorta (Madrid), and José Elguero (Madrid)


Data fabrication

The article “Paper Mill Hits RSC Journals” (C&EN, Feb. 1, 2021, page 15) has a euphemistic title and was not written in plain English that most people understand, particularly the younger generation. I doubt that the words paper mill mean anything to a young person in this digital age.

The proper words to use are fraud and data fabrication and people and enterprises that commit those acts for personal gain.

It is very important that graduate and undergraduate students and faculty be made aware that fraud and data fabrication are dishonest and criminal. It is equally important that academic institutions take proactive steps to prevent fraud and data fabrication and also take steps to ensure the quality and reproducibility of published results.

It is important that graduate and undergraduate students and faculty be made aware of the importance of reproducibility and avoiding cherry-picking data to support preconceived notions. Please see C. Glenn Begley articles (Nature 2015, DOI: 10.1038/525025a, and 2012, DOI: 10.1038/483531a) for examples of issues related to the lack of reproducibility and a Nature article by Monya Baker (2016, DOI: 10.1038/533452a) that describes how widespread the lack of reproducibility problem is.

There are many more recent articles on widespread inability to reproduce results because of various improper research behaviors.

Fraud and data fabrication are also found in the laboratory test for product batch data at many pharmaceutical companies, according to US Food and Drug Administration and European Medicines Agency inspection reports, resulting in the consumer getting subpotent and substandard drugs.

Helena Champion
Palm Beach, Florida

Editor’s note: The US National Academies of Sciences, Engineering, and Medicine published the report “Reproducibility and Replicability in Science” in 2019..


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.