I took a cusery glance at it. From what I can tell, it doesn't have any data accurate to this universe after about element 110. So info on 111 and onwards is probably made up. And info from element 119 and up is definately made up, as we've only been able to make up to 118 and it doesn't last long enough to make much study of it. There's expected to be an "island of stability" at around 114 where you can get isotopes that don't instantly decay to nothing --or so I'd read. But AFAIK that hasn't been confirmed. Also AFIAK numbers larger than that are expected to continue the trend of instant decay. Which is to say, it's expected that elements larger that 114 or so will not be stable enough to make anything out of them, which is currently the case for anything over about 100, I think, though I am not sure on that.
However, while looking into nuclear isomers I learned there are examples of very unstable elements being excited to high energy states with very difficult transition paths. Which is to say, the get up a state they don't like climbing down from. Thus, these meta-stable isomers remain stable for several orders of magnetude longer than at the ground state. Hasnium, I think is the prime example. So I could imagine a time where very heavy elements are manufactured and then are rapidly energized into a isomer state of long duration to be used as a building material. Industrial replicators would make this process easier. Of course, woe to any person or machine near any such object if it decides to "go to ground", as it were, all at once! It's Vaporization Time!
Also, I have read that there is theoretical evidence that atomic elements over 125 or so may be impossible, as the speed at which an inner electron would have to orbit such a nucleus would surpass the speed of light. Of course, that's with modern understanding, which is incomplete, at best.
However, I never bought that "dilithium" was a made up of a heavy element. Some of the recon explanations are cool and I could see how it might be possible, but I never bought them... especially after watching someone carrying a tray of dilithium crystal the size of a cat around in their hands. Plutonium is too heavy for that AFAIK. Let alone some super heavy element!