Introduction: I've spent some fair amount of time thinking about inventing an element to make part of my world easier for me. In this case, it is an LTA gas which I gave the WIP name LAL-gas (Leichter Als Luft - the german equiv. to Lighter Than Air). The gas is intended to be used to lift things from the ground (namely airships) with about 400-500% the lifting power of existing lifting gases (Hydrogen/Helium), as inert.

The LAL-gas itself would be the product of a reaction between the LAL-solid (I was thinking of it being a salt or sulfate) and diluted sulfuric acid (e.g. Acid Mine Drainage or Acid Rock Drainage) of high temperature. The result would be one: the LAL-gas itself; and two: a byproduct that is highly flammable, but will burn through rather fast. Said byproduct would hence be converted to smoke (soot, and co) and ash (probably poisonous).

Question: Is this lifecycle feasible? I.e. could it work as described or are there any inherent problems/stumbling blocks?

Addendum: The names are WIP names, proposals for names are welcome but not scope of this question. Proposed changes to the lifecycle in order to make it work are welcome.

Lore: You grew up with these ships dominating the skies, so did I to be honest. But did you know that the gas allowing for this was discovered rather by accident than on purpose? Tales say it was a little boy, just like you, that, while playing hide'n'seek, hid in an outcropping in the woods. There he stumbled and slid down into one of the many caves of the area, where he found plants with leaved as big as lily pads floating along the ceiling above a funny smelling pond. Upon touching the water he burnt himself, making him run back to his mother crying. The father had him show what burnt his fingers - which led to the accidental discovery of one of natures greatest gifts to us. You see, these purple stones village square is made of, they will react to sulf... Oh well, enough talking. Go out and play. I don't think your mother will have dinner ready for another hour.

  • $\begingroup$ You're basically asking if the idea of a gas with lifting power 4-5 times that of the most lightweight gases known is feasible? $\endgroup$
    – user
    Commented Jun 24, 2015 at 7:53
  • $\begingroup$ @MichaelKjörling no, I'm asking about the feasibility of the way it is produced/made (will add clarification, thanks) $\endgroup$
    – dot_Sp0T
    Commented Jun 24, 2015 at 7:55
  • 3
    $\begingroup$ You can decide for yourself how much handwavium do you wish to use. Inventing a new element that is impossible according to physics (4-500% lighter than a single proton) is such a huge step from hard science fiction that the described chemistry is nothing in comparison. If you are comfortable with the idea of creating something new and impossible, then feel free to do so. If you wish to have a solid scientific foundation, then feel free to do so. $\endgroup$
    – zovits
    Commented Jun 24, 2015 at 11:18
  • $\begingroup$ @Secespitus so you can't see that one? $\endgroup$
    – dot_Sp0T
    Commented Sep 5, 2017 at 11:37
  • $\begingroup$ @dot_Sp0T Nope. $\endgroup$
    – Secespitus
    Commented Sep 5, 2017 at 11:50

4 Answers 4


Ignoring the fact that your lifting gas is physically impossible, and looking at the chemistry:

"LAL-gas" is effectively inert, which means that chemical reactions forming it tend to be energetically favorable, while those dissociating it tend not to be. It will tend to form whenever there's enough energy around to dissociate its precursors from the substance they're currently bonded to; since you describe the other product of your LAL-gas-producing reaction as highly flammable and burning quickly, this LAL-solid probably isn't very stable. A chemical precursor to LAL-gas will likely break down into LAL-gas + byproduct in the presence of heat, or strong ultraviolet light, or any other source of energy.

My recommendation would be for your "LAL-solid" to have LAL-gas encapsulated in the crystalline structure of the stone rather than bonded to it. Dilute acid disrupts the structure and releases the gas without completely breaking down the stone, where concentrated acid would destroy both stone and gas. LAL-gas will act to keep the solid from burning, since heating the solid will release the gas from the surface, displacing oxygen and extinguishing any fire. Depleted LAL-solid, on the other hand, will be highly flammable because there's no gas to provide the inerting effect.

This has the side benefit of not needing to worry about the lifting power of LAL-solid: a stone that is 1% LAL-gas would not be appreciably different from one that is 0%, whereas if LAL-solid were chemically bonded, the proportion of whatever gives LAL-gas its effectively negative mass would probably be much higher, and the stone would have an anomalously low density.


While the other answers are correct, that it is difficult to imagine a molecule less dense than hydrogen, the real reason this gas can't exist is because even a vacuum isn't that good at lifting. Even if you were to make an effectively massless gas it would still only have about 7% better lifting power than hydrogen in our atmosphere. For something to have 400-500% more lifting power would require it to have negative mass. The calculations are shown here: https://en.wikipedia.org/wiki/Lifting_gas

  • $\begingroup$ What if the planet's atmosphere is denser so hydrogen fits the bill. E.g. look at a balloon on Venus! Or, the substance does not work via boyancy but is repelled from the ground somehow. $\endgroup$
    – JDługosz
    Commented Jun 25, 2015 at 21:37

The simple answer is, that this can't be answered.

The substance you asked for doesn't exist, and is pretty close to impossible to exist. From that you can see that it's impossible for us to speculate as to how it might be created ... because it doesn't exist!

The sort of reaction you describe sounds plausible in order to generate "something", and that's all you can really achieve in this situation.

  • $\begingroup$ After reading your answer, it seems rewriting the question to ask for plausibility over feasibility would be the way to go. But that would more or less invalidate your answer. As you've got quite some experience on the site, do you think I should still go rewriting it? (It would e.g. help as a reference case for others trying to validate their inventions) $\endgroup$
    – dot_Sp0T
    Commented Jun 24, 2015 at 10:00
  • $\begingroup$ If the rewrite substantially changes the question then just ask it as a new question :) $\endgroup$
    – Tim B
    Commented Jun 24, 2015 at 10:33
  • 1
    $\begingroup$ @dot_Sp0T What Tim said. It happens every once in a while that the answers to a question make you realize that you really asked the wrong question to begin with. In that case, accepting that the first question turned out differently than you intended, and asking a completely new question, is often the best thing to do. $\endgroup$
    – user
    Commented Jun 24, 2015 at 11:01

Look at the periodic chart. H - Hydrogen has 1 proton. He - Helium has 2 protons. Protons produce the vast majority of the weight of an atom, like the sun has most of the mass of the solar system.

Anything less than 1 proton is not an atom nor would it be an element. It would have to be some kind of electron cloud, which of course couldn't be made by a simple chemical reaction.

Periodic Table of Elements

  • $\begingroup$ Protons make up about half the mass of light elements (except hydrogen, where it's almost 100% averaged over natural hydrogen). Neutrons make up the other half, and more than half the mass of heavy elements. $\endgroup$
    – user25972
    Commented Dec 21, 2016 at 5:43

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