 Guillermo Restrepo focused his interest on how formal tools can be applied to chemistry. With José Luis Villaveces, he noted the resemblance between Leibniz’s and Lavoisier’s programs regarding a lingua philosophica for understanding nature (Restrepo and Villaveces 2011) and reviewed the origins of mathematical thinking in chemistry (Restrepo and Villaveces 2012). Restrepo also analyzed the mathematical aspects of the periodic law (Restrepo and Pachón 2007) and considered the different foundational aspects of the field called “mathematical chemistry” (2013; Restrepo and Villaveces 2013). Restrepo has been working in Germany since 2014 where he still produces interesting contributions to the philosophy of chemistry.