I'm aware that the densest stable element is osmium at 22.61 g/cm3.

And that there are unstable elements such as hassium and meitnerium which are predicted to have densities of 41 g/cm³ and 37.4 g/cm³ respectively, but those have half-lives of only a few seconds.

I'm also aware that stuff like quark-gluon plasma has been made in the LHC that is also much denser.

But I'm also aware that the main reason for osmium's high density is not its number of nucleons — there are a few stable elements that have more nucleons but are less dense, such as lead and gold — so much as its chemical structure leading its nuclei to being closer together.

Is there some alloy or compound that has a higher density than osmium that has been produced in macroscopic quantities and, after having been produced, remains denser than osmium at 1 atm of external pressure?

Edit: I've already seen Is there a compound denser than the densest element. But while that might have been the title of that poster's question, it wasn't the crux of what they were after. They really wanted to know what they could buy that was denser than mercury for use as a prop. And the answers only address that part, rather than the crux of my question. Furthermore, I am aware that such materials do exist; I'm specifically asking which ones have been produced here on earth in macroscopic quantities at 1 atm.

  • $\begingroup$ Seems to be a duplicate of physics.stackexchange.com/q/60022 $\endgroup$ Feb 16, 2017 at 20:19
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    $\begingroup$ @dmckee Maybe in question title alone. That question was specifically asking the cheapest way to actually get his hands on a material more dense than mercury. And the only answers talk about pure elements and their prices. I'm specifically asking about alloys and compounds that are denser than the densest thing mentioned in that question and it's answers. It's not a duplicate. $\endgroup$ Feb 16, 2017 at 20:24
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    $\begingroup$ I suppose that question mentions the possibility of alloys heavier than osmium, but that was not really key to his question. And the accepted answer does not answer my question. $\endgroup$ Feb 16, 2017 at 20:25
  • $\begingroup$ What do you mean when you specify "has been produced"? Does natural production by astrophysical sources count? In that case, you probably can't get much more dense than the matter at the core of a neutron star. There's definitely a macroscopic amount of that kind of matter, given that neutron stars are certainly macroscopic objects and there are a large number of them in the universe. $\endgroup$ Nov 17, 2019 at 11:10
  • $\begingroup$ @probably_someone I meant to imply either found or produced here on earth. But your suggestion of neutron star material would be ruled about by the stipulation I gave about remaining so at 1 atm of external pressure. Neutron star matter would explode at 1 atm. After all, neutron star material is what you get if you take any element and compress it sufficiently. I used "material" rather than "element" so as not to exclude the possibility that there is an alloy that is denser than osmium on its own. $\endgroup$ Nov 18, 2019 at 8:10

1 Answer 1


The density of a given material is due to its crystal lattice. If you read through crystallography textbooks you will find that centered cubic system like that of gold is the most densely packed one. Though the nano-materials, basically nano powders, may have density exceeding normal materials.

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    $\begingroup$ This doesn't answer the question. $\endgroup$
    – user4552
    Nov 17, 2019 at 14:02

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