The nucleosynthesis of superheavy atoms such as transactinides is an exciting area of nuclear physics, but not much of a playground for chemistry because

My question is: what is the heaviest atom ever used in chemistry? For this I define chemistry as “making a compound with the atom (molecule or material) and characterizing it to some extent”.

The one source I found on the topic is “Critical evaluation of the chemical properties of the transactinide elements (IUPAC Technical Report)”, dated 2003, but it seems quite old for such a rapidly developing field. Also, despite being title “chemical properties” it mostly reports on physical properties.

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    $\begingroup$ I'd say chemistry ends somewhere around Z=100. Sure, there were some examples of reactions involving heavier elements, but it's not like they were used in chemistry; it's more like an elaborate chemical setup built around a tiny bunch of atoms in the hope of catching a glimpse of their fleeting existence. You can't really characterize a lone molecule. Or maybe you can, but it's more about physics. $\endgroup$ Aug 9, 2016 at 9:02
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    $\begingroup$ The Chemistry of the Actinide and Transactinide Elements, 2010 edition, reports compounds up to hassium (Z=108), namely $\ce{HsO4}$, and as-of-then unsuccessful attempts at chemistry up to copernicium (Z=112), dated around 2002-2003. Not sure about anything more recent. Wikipedia agrees that meitnerium (Z=109) is currently the first element with no reported experimental chemistry. $\endgroup$ Aug 9, 2016 at 9:48
  • $\begingroup$ Although it's completely hypothetical, Periodic Videos postulates the heaviest possible tetrahedral molecule. $\endgroup$ Apr 28, 2023 at 2:46

2 Answers 2


According to Adsorption behavior of super-heavy elements (Z [greater than or equal to ] 112) on metal and inert surfaces :

Nowadays the research focusses on the chemical properties of the element 114. So far, two gas chromatography experiments to study the interaction strength of element 114 with a gold surface have been performed with conflicting results. One experiment [reference 1] reported a weak interaction of element 114 with a gold surface, leading to adsorption only at very low temperatures of approximately –90°C, while in the second experiment [reference 2] adsorption on gold has been observed at the room temperature, indicating a much stronger bond between element 114 and gold.

See also the earlier: Chemical characterization of element 112 :

We therefore conclude that the stronger adsorption interaction of element 112 with gold involves formation of a metal bond, which is behaviour typical of group 12 elements


The heaviest element with a known compound, as of this writing, is copernicium, atomic number 112, which has been combined with selenium:

Because the lighter group 12 elements often occur as chalcogenide ores, experiments were conducted in 2015 to deposit copernicium atoms on a selenium surface to form copernicium selenide, CnSe. Reaction of copernicium atoms with trigonal selenium to form a selenide was observed, with $-ΔH_{ads}^{\ce{Cn}}(t-\ce{Se}) > 48$ kJ/mol, with the kinetic hindrance towards selenide formation being lower for copernicium than for mercury. This was unexpected as the stability of the group 12 selenides tends to decrease down the group from ZnSe to HgSe.[1]

Cited Reference

  1. Paul Scherrer Institute (2015). "Annual Report 2015: Laboratory of Radiochemistry and Environmental Chemistry" (PDF). Paul Scherrer Institute. p. 3.

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