Iridium with a density of $22.56$ g cm-3 & osmium with $22.59$ g cm-3. Data from their respective Wikipedia pages.

Only these two naturally occurring elements have such a high density. I wish to know why. Also If possible the factors affecting the density of any/every elemental substance.

  • $\begingroup$ Welcome to chemistry.SE! If you had any questions about the policies of our community, please ā€ˇvisit the help center. $\endgroup$ – M.A.R. Dec 14 '15 at 14:03
  • $\begingroup$ Well, by definition, at least one element will be the densest. So you are asking why particular elements adopt a close-packed crystal structure (various reasons) and have heavy nuclei. I'm not sure that there is a 'simple' explanation for that. $\endgroup$ – Jon Custer Dec 14 '15 at 14:25
  • 5
    $\begingroup$ The reasons behind osmium's density are explained here $\endgroup$ – ron Dec 14 '15 at 14:26