1 Introduction

Chemistry scholars in the late 1990s were amid the early adopters of open access (OA) publishing in the digital era, namely of publishing scientific articles and reviews in journals freely accessible on the internet. Writing in 2007 in one such new OA journal, Hodd reported that in chemistry there were “currently over 50 open access journals” [1]. Examples include Arkivoc publishing OA papers in synthetic organic chemistry since 2000, and the Beilstein Journal of Organic Chemistry launched in 2005. Both journals do not require authors to pay an article processing charge (APC).
Publishing scientific articles accessible without restrictions largely improves the visibility of the freely accessible study. Accordingly, comparing the number of citations of articles in physics published between 1992 and 2002 made OA by self-archiving with the citations of articles from the same journals that were not made OA by their authors, in 2004 Harnad and Brody first unveiled that the OA/non-OA citation ratio varied between 2.5 and 5.7 [2].
As it happened with preprints [3], the early successful adoption of OA publishing amongst chemistry scholars subsequently faded away. As a result, with less than 20% papers being freely available in 2016 chemistry was found to be the discipline with the lowest fraction of OA papers amid 100,000 research papers published between 2009 and 2015 [4]. For comparison, the same statistical analysis found that more than 50% of biomedical research and mathematics papers were freely accessible.
The advantages in terms of enhanced visibility, number of citations, career and funding opportunities of open science, however, are too numerous for chemistry scholars continuing to ignore open science. In 2018, the percentage of chemistry papers published as open access (in the Web of Science category “chemistry multidisciplinary”) increased to 26% of the total [5].
Showing evidence of enhanced impact of OA journals, in 2017 the top three most cited multidisciplinary scientific journals were all fully OA journals (Table 1).
Table 1 . Top five multidisciplinary scientific journals ranked by number of citations in 2017. [Source: Clarivate Analytics, 2018].