new chemistry question for your noses

[swan_tower]

How about sulfates? Do they tend to smell of sulfur, or not?

(This is what I get for deciding to put faerie science in my books. I have to figure out how the real science goes, then figure out how the fantasy version goes, then figure out how to describe the fantasy version, based on but maybe not identical to how I'd describe the real version. If I ever do this to myself again, somebody please kick me.)

Comments

[andria harkey (from livejournal.com)]

Sulfates? Not that I can remember, at least with any I've worked with. We use calcium sulfate as a desiccant, but it's odorless as far as I can tell. Organic compounds that contain sulfur, like thiols, are more likely to be smelly. There are some that can stink up a whole lab, even with the excellent ventilation.

[attackfish.livejournal.com]

No, they don't, which makes them really dangerous to me, as I'm allergic to all of them.

[zunger.livejournal.com]

Quoth Wikipedia's page on Sulfur: "Organosulfur compounds are responsible for the unpleasant odors of decaying organic matter. Thiols and sulfides are used in the odoration of natural gas, notably, t-butyl mercaptan. The odor of garlic and "skunk stink" are also caused by organosulfur compounds. Not all organic sulfur compounds smell unpleasant; for example, grapefruit mercaptan, a sulfur-containing monoterpenoid is responsible for the characteristic scent of grapefruit. It should be noted that this thiol is present in very low concentrations. In larger concentrations, the odor of this compound is that typical of all thiols."

There's a lot of variation in the way various sulfates smell. The characteristic sulfur smell is actually that of hydrogen sulfide, which is outgassed by anything that has weakly-bound sulfur atoms and is exposed to air; but sulfate ions tend to hold together pretty well, so they don't get an automatic smell.

[cepetit.myopenid.com (from livejournal.com)]

And that just made me realize that I meant literally "sulfates," not "sulfur-containing compounds" (for which Wikipedia is actually reasonably accurate).

[cepetit.myopenid.com (from livejournal.com)]

Most naturally occurring sulfates, and many sulfides, are nonvolatile at room temperature anyway, so you'd have to try really hard to smell them anyway. The "smell" associated with them is usually that of whatever reagent they've been dissolved in, plus side-chain reactions in that reagent.

[anghara.livejournal.com]

Sulphates are salts, and salts rarely have a particularly memorable stink (cue me shaking my fist at the TV as Captain James Know-it-all Kirk pokes a finger into a fall of white powder, sniffs at it, gives it an experimental lick, and pronounces it to be potassium nitrate. Oh, REALLY.) SulPHIDES, though, can - think hydrogen sulphide and the immortal rotten egg stink of that.

Not remotely helpful, probably, but there you are.

[rosa-g.livejournal.com]

Sulfates (SO4^2-) themselves don't have a smell... sulfides (S^2-) DO!

Occasionally a sulfate will react and create a sulfide (usually H2S), thus resulting in a smelly fish/rotten egg smell.

[rosa-g.livejournal.com]

I LOVE that you are incorporating science in the new book btw! I spoke precisely of this topic (science in fantasy books) in my Sirens presentation! :)

[shui-long.livejournal.com]

Inorganic sulphates (sorry, but I am not going to use American spelling) are inert, and generally odourless. Plasterboard (dry-lining, wallboard, etc) is largely made of Calcium Sulphate. As far as I can remember, commercial crystalline iron sulphate and copper sulphate may have a slight odour, but I can't think how to describe it. Organic materials containing sulphur can be a different matter, but I assume that's not what you're dealing with here.