View Full Version : The anti-soluble?

09-05-2010, 10:55 AM
Is there a material known to man, either in existence or theory, that would be incapable of being dissolved by a solvent?

Also, is there any substance which is or would be incapable of being dissolved by water?

09-05-2010, 11:08 AM
Umm oil? Fats?

09-05-2010, 11:11 AM
Any noble metal is highly resistant to corrosion (e.g. platinum/gold), and Iridium is the most corrosion resistant metal known to man. Basically only a few types of molten salts can attack it.

09-05-2010, 03:20 PM
And plenty of molecules have very strong bonds that make them even more resistant than elements.
Although there is a difference between insoluble and corrosion resistant.

09-05-2010, 08:43 PM
Any highly cross-linked polymer will be insoluble in solvents, simply because the molecules are so large (once you pass the gel point, which is when there is so much cross-linking between chains that the material is really one big molecule). At that point, the material will simply swell if it would otherwise be soluble, which is where we get super-absorbent diapers.

Other than that, any material will be soluble to some extent in any solvent, even if it's in immeasurably small amounts. What do you need this material for? That might help us make better suggestions.

09-05-2010, 08:56 PM
Fats don't dissolve, at best they form an emulsion.

09-05-2010, 09:37 PM
diamond isn't soluble in anything much

There are plenty of inorganic salts that are highly insoluble in water.
What pH water were you asking about?

09-05-2010, 10:45 PM
It seems to me that part of the question is missing here. What's the point of naming the insoluble material? There are a lot of variations on the theme, including--

--Definition of insoluble--some things are considered insoluble for a given purpose, but not for another--e.g. crude oil in sea water. It mostly doesn't dissolve, but the fringes of the definition can be important. Silica sand is considered insoluble in water, but over gelogical time, that's not true.

--Special conditions. Teflon is pretty insoluble in water, as are some metals, as mentioned. But there are always some situation where the definition fails. Suppose you put teflon or iridium in a high temp plasma, such as the sun. If it turns into a soup of nucleii and electrons, is that dissolved?

09-06-2010, 02:35 AM

I know they put it in liquors these days, but it's pretty darn insoluble even in alcohol according to what I know (which ain't that much).

09-06-2010, 03:19 AM
You can dissolve gold in aqua regia, a 3:1 mixture of Hydrochloric and Nitric acids. In fact, there's an interesting story about that, which I'll let Wikipedia relate:

When Germany invaded Denmark in World War II, the Hungarian chemist George de Hevesy dissolved the gold Nobel Prizes of Max von Laue and James Franck in aqua regia to prevent the Nazis from stealing them. He placed the resulting solution on a shelf in his laboratory at the Niels Bohr Institute. It was subsequently ignored by the Nazis who thought the jar—one of perhaps hundreds on the shelving—contained common chemicals. After the war, de Hevesy returned to find the solution undisturbed and precipitated the gold out of the acid. The gold was returned to the Royal Swedish Academy of Sciences and the Nobel Foundation who recast the medals and again presented them to Laue and Franck.

09-06-2010, 03:29 AM
Aqua Regia, huh? Off hand, I'd say that anything that's insoluble except in a specially-formulated acid is pretty darned insoluble.

Not trying to be offensive, here, just saying'...


09-06-2010, 03:55 AM
Perhaps so, but we still don't know exactly why the OP wants it.

09-06-2010, 05:40 AM
Sorry for the long wait.
I was mulling over an idea for a story in which some humans have discovered an extraterrestrial(by which I mean not of earth, not necessarily made by aliens, at least as far as the characters concerned) object.
I wanted this object to be covered in...something...that would stand up to attempts to dissolve/corrode it away and reveal the object beneath, even over prolonged periods by such things as superacids or superbases. (I'm actually not too sure of the process they would use if attempting to chip/strip away the material failed.)
I wanted a scientific explanation in the story of why they couldn't dissolve the material, at least without waiting for a few geological epochs to pass, if ever.

09-09-2010, 01:40 AM
They'd probably just physically scrape it off. Strong chemical bonds does not translate into hard physical properties. Teflon is extremely chemically resistant, but comparatively soft.

09-09-2010, 01:46 AM
A superacid would run the risk of instantaneousnly destroying the artifact. That is why archeologists most use purely physical methods, chisels, compressed air, brushes and seives....

09-09-2010, 08:31 PM
A superacid would run the risk of instantaneousnly destroying the artifact. That is why archeologists most use purely physical methods, chisels, compressed air, brushes and seives....

Hi Veinglory--Nice to run into you again.

I was going to make the same point, e.g. that if I wanted to enter a strange artifact, corrosives wouldn't be my first thought. Actually, the best place to start would probably be non-invasive techniques--x-rays, sonograms, or some such.

Arthur C Clarke did this trick in 2001, A Space Oddessy, and Larry Niven had nearly indestructible* spaceship hulls in his known space series. Clarke didn't explain why the monolith was so tough and inscrutable, he just wrote it so. Niven provided a techno-babble explanation that involved a single huge molecule stabilized by some kind of electrical field.

*As it turned out, of course, the General Products hulls could be destroyed by antimatter. That's still pretty damn tough.