To cite webchem in publications use:

  Szöcs E, Stirling T, Scott ER, Scharmüller A, Schäfer RB (2020).
  “webchem: An R Package to Retrieve Chemical Information from the
  Web.” _Journal of Statistical Software_, *93*(13), 1-17.
  doi:10.18637/jss.v093.i13 <https://doi.org/10.18637/jss.v093.i13>.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {{webchem}: An {R} Package to Retrieve Chemical Information from the {W}eb},
    author = {Eduard Sz\"ocs and Tam\'as Stirling and Eric R. Scott and Andreas Scharm\"uller and Ralf B. Sch\"afer},
    journal = {Journal of Statistical Software},
    year = {2020},
    volume = {93},
    number = {13},
    pages = {1--17},
    doi = {10.18637/jss.v093.i13},
  }

In addition to citing webchem in publications, please check attribution
guidelines for any data sources you accessed.  Links to documentation
can be found in help files for webchem functions.