Wikipedia:Reference desk/Archives/Science/2024 August 7

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August 7

Density of Iridium and Osmium

Note A at Iridium says

"At room temperature and standard atmospheric pressure, iridium has been calculated to have a density of 22.65 g/cm3 (0.818 lb/cu in), 0.04 g/cm3 (0.0014 lb/cu in) higher than osmium measured the same way. Still, the experimental X-ray crystallography value is considered to be the most accurate, and as such iridium is considered to be the second densest element" with a reference to https://technology.matthey.com/content/journals/10.1595/003214089X3311416

I am curious: has anyone ever directly measured the density of a pure crystal of each by immersing them in water and experimentally confirmed these calculations? Or is the difference too small to measure using conventional methods?

Looking at Isotopes of iridium and Isotopes of osmium, would the answer be different if the pure crystals were made from the heaviest stable isotope? Are we even able to seperate the isotopes of iridium and osmium?

Note the "At room temperature and standard atmospheric pressure". See https://technology.matthey.com/content/journals/10.1595/147106714X682337 for some other temperatures and pressures.

Interesting but not reliable: https://www.answers.com/natural-sciences/What_is_densest_material_in_world The bit about plutonium surprised me.

--Guy Macon Alternate Account (talk) 15:07, 7 August 2024 (UTC)

Sure we can separate the isotopes. Isotopically pure ¹⁸⁴Os (the lightest stable-ish isotope) should be less dense than isotopically pure ¹⁹³Ir. Double sharp (talk) 12:39, 9 August 2024 (UTC)