Relativistic effects are observed with many other 6th and 7th period elements. For example, the yellow colour of gold and caesium comes from altered electron energy levels due to relativistic orbital contraction, so are the special catalytic and bonding properties of platinum.
replyhttps://en.wikipedia.org/wiki/Relativistic_quantum_chemistry
OP claimed relativistic effects explain why mercury is liquid at room temperature. That may be part of the story, but it isn't the whole thing, since other heavy elements are not liquid at room temperature.
replyExplaining relativistic effects in plain text forums to a general audience is a big ask, but here is a link to the first study[0] that gave evidence but it has long expected.
reply[0] https://onlinelibrary.wiley.com/doi/epdf/10.1002/anie.201302...
It also has an effect, it is a small correction in the energies and bounding. Sometimes it's enough to change the color or state, sometimes it's a correction like making it 1% softer or harder and is not interesting unless you are a specialist.
replyIt would be the element underneath it which is synthetic. But it is interesting that all the elements in that row are soft or brittle in pre form or in some compounds.
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