Help
lexigame.com the home of unique word games

Lexigame Community
November 20, 2017, 12:09:53 PM *
Welcome, Guest. Please login or register.

Login with email, password and session length
News:
 
   Home   Help Search Calendar Login Register  
Pages: [1]
  Print  
Author Topic: Chemical confusion  (Read 702 times)
mkenuk
Glossologian
**
Posts: 1314



View Profile
« on: April 22, 2017, 10:49:05 AM »

re the recent interdict game.

I know very little about science - a smattering of elementary Physics, Chemistry and Biology retained from my schooldays - so can someone please explain why nitric is rare in Chi but nitrite is common?
Nitride also appeared, and that too was rare. Not sure about nitrate - there was no 'a' in the game.

 Huh?

Logged
Calilasseia
Lexicomane
***
Posts: 137


Pass the dissection kit ...


View Profile
« Reply #1 on: April 24, 2017, 12:24:03 PM »

This one puzzles me somewhat too, given that nitric acid is frequently encountered in chemistry classes throughout the developed world. Even more weirdly, the inbuilt spell checker in Google Chrome highlights 'nitric' as a spelling error!

Nitrates, which are the salts formed when nitric acid is reacted with metal oxides or hydroxides, would also seem to be a candidate for common usage. Especially given the number of gardeners around the English speaking world who use nitrate fertilisers - one of which, ammonium nitrate, is also a powerful oxidising agent in the right circumstances, and consequently found itself being pressed into use for terrorist bombs in the past. Further in the past, Amatol, a mixture of ammonium nitrate and TNT (trinitrotoluene), was a constituent of World War II era high explosive bombs. Some nitrates are also potent vasodilators, for example nitroglycerine (known in medical circles as glyceryl trinitrate or GTN for short), which is used for treatment of angina pectoris and emergency relief from cardiac arrest. This substance is so powerful a vasodilator, that a 400 microgram dose is enough for most people. If you're not careful with the dosage, your blood pressure can plummet dramatically, and "GTN headaches" are a known condition arising in heart patients adjusting to GTN medication.

Nitrides, on the other hand, are somewhat more specialised. Metal nitride layers are sometimes used in high performance internal combustion engines to improve thermal resilience, and have in more recent times featured as coatings on high performance motorbike forks. Several of them are classed as "refractory materials", which means they'll withstand high temperatures, up to and including the temperatures inside blast furnaces. However, some nitrides are, shall we say, a little touchy to handle. The stable ones have many uses, such as gallium nitride, which is used to make blue LEDs, and boron nitride is a high-temperature lubricant suitable for use in high-performance jet engines. On the other hand, silver nitride is a contact sensitive explosive. Mercury nitride doesn't even persist long enough after synthesis to be properly characterised with respect to its internal bonding, and enjoys fleeting existence as part of an equilibrium mix of various complexes.

Nitrites, one step down from nitrates, are used extensively for meat curing, in particular for stopping the very nasty Clostridium botulinum from growing inside sausage meat. Whilst there are some health issues arising from long term consumption of nitrites in cured meat, they're way less problematic than a hideous death from botulinum poisoning. As a consequence, they'll still feature in cured meats until a better substitute is found. In addition, sodium nitrite is used as in intravenous injection in cases of acute cyanide poisoning, along with other compounds whose purpose is to provide a sudden boost in Fe3+ ions in the bloodstream, to mop up the cyanide ions before they can latch onto haemoglobin and shut down your oxidative metabolism for good. Again, if you're in the position to need this, you'll be far more worried about not dying rapidly from cyanide poisoning, than any chronic effects from the nitrites.

A far less familiar group of nitrogen compounds, the azides (containing an N3- ion), I've dealt with elsewhere, as many of these are hideously, violently explosive, and some are extremely difficult to handle even by expert chemists, because they'll blow up at the merest whiff of disturbance. However, some of these have medical uses also - azidothymidine is an anti-HIV drug, and azide groups bonded to complex, high molecular weight organic molecules are finding increasing pharmaceutical utility. Bonding azide groups to big organic molecules tends to stabilise them somewhat, and in any case, the typical clinical dosage is of the order of 1 to 2 milligrams, so they're not going to be a  major explosive problem even if they weren't nicely stabilised. Substances like cyanogen azide or mercury azide, on the other hand, are chemicals you would not want to be close to even if you were a skilled chemist, unless you had very compelling reasons for working with them. These molecular hooligans will introduce you to flying glass and shrapnel with frightening ease and regularity, and can blow you to kingdom come even in 1 to 2 gram quantities. Heavy metal azides are trembling on the verge of not existing immediately after you've made them, and they'll frequently blow up just because you left the crystals to get warm on a sunlit windowsill. Though most chemists would regard forming crystals of these compounds as a particularly spectacular kamikaze act.

One of the weirdest nitrogen compounds you'll come across is something called Millon's Base, [Hg2N]+, which forms a weird array of salts with peculiar properties. One frankly insane scientific paper I've encountered recently featured bolting a nice, explosive azide group onto this beast - the resulting Millon's Azides are molecular berserkers with a penchant for destroying laboratory glassware, and separating you from your limbs if you're foolish enough to make them in quantity. No prizes for guessing that research into these crater-bait compounds enjoys a lot of military funding.
Logged

Remember: if the world's bees disappear, we become extinct with them ...
Alan W
Administrator
Eulexic
*****
Posts: 3332


Melbourne, Australia


View Profile Email
« Reply #2 on: August 06, 2017, 11:16:20 PM »

Currently nitrite and nitrate are the only nitrogen related words to be classed as common, along with nitrogen itself. Of the three words nitrite, nitric and nitrate, nitrite is far and away the least frequently appearing word in general publications. It's mostly used in connection with the use of nitrites in curing meats, as mentioned by Calilasseia. So I agree it should become rare.

I think it's correct for nitrate to remain common - the word does get used quite often, and I think most people, even if they have little scientific knowledge, would be aware that there are such things as nitrates. As for nitric, it's probably a borderline case, but I'm comfortable leaving it as a rare word.
Logged

Alan Walker
Creator of Lexigame websites
a non-amos
Cryptoverbalist
*
Posts: 965



View Profile
« Reply #3 on: August 07, 2017, 03:56:01 AM »

Here in Virginia the weather is hot and humid.  This would be the perfect time to remove "nitrite" from the list.

After all, you know what they say . . .













Strike the ion while it's hot.

Logged

Carpe digitus.
(Roughly translated, this is possibly the world's oldest "pull my finger" joke)
anona
Lexicomane
***
Posts: 138


View Profile
« Reply #4 on: August 07, 2017, 05:03:20 AM »

And there was I, a total ignoramus when it comes to sciency things, thinking about the nitrites leaking out every time I cook bacon.
Logged
mkenuk
Glossologian
**
Posts: 1314



View Profile
« Reply #5 on: August 07, 2017, 03:12:59 PM »

Thanks for the research, Alan. Painstaking as always.

And thanks for the chemistry lesson, Calilasseia. I think I understood most of it, just don't ask me too many questions.

Your final comment about the warmongers who are constantly looking for new ways to destroy things is unfortunately too true.
Logged
Calilasseia
Lexicomane
***
Posts: 137


Pass the dissection kit ...


View Profile
« Reply #6 on: September 07, 2017, 06:26:25 PM »

Thanks for the research, Alan. Painstaking as always.

And thanks for the chemistry lesson, Calilasseia. I think I understood most of it, just don't ask me too many questions.

Your final comment about the warmongers who are constantly looking for new ways to destroy things is unfortunately too true.

I've mentioned Thomas Klapötke before, a German chemist who has built a career out of synthesising what are known euphemistically as "energetic compounds" (read: explosives). He and his lab staff work with molecules that scare the living daylights out of most other chemists.

For example, there's a nicely unstable chemical, rejoicing in the name of N-amino azidotetrazole. Basically, it's a ring of five atoms, four of these being nitrogen atoms, with a solitary carbon to stabilise things, and the odd hydrogen atom seemingly bolted on as an afterthought, to which has been added (to one of those trembling nitrogens in the ring) an amino (-NH2) group. This molecule will decompose at the drop of a hat (or even if you let a few specks of dust fall on the crystals!), and most chemists think very long and hard before being asked to make it. For Klapötke and his merry men, however, this seething mass of bonding energy is simply the starting point for some of their, shall we say, more edgy preparations. One of which packs no less than fourteen nitrogen atoms together, in ways that those nitrogen atoms really resent being packed together. You know that  Klapötke has some strange aesthetic tastes in molecules, when he calls this stuff "exciting". "Excitable" is probably much nearer the mark, and most of us would reach, as Derek Lowe did when introducing me to this beast, for phrases such as "crater bait". Apparently the lab work on this molecule from hell involved over two dozen explosions, and shrapnel in rather more quantities than most of us would ever wish to see in a lifetime, let alone the 14 days or so spent trying to tame this stuff.

No prizes for guessing where he's frequently invited to go on his trips across the Atlantic. If it's a military lab with lots of uniformed types looking over your shoulder (and then reaching for the running shoes when the chemists tell them what's being cooked up today), then Klapötke is given an invite, and racks up a healthy collection of air miles as a result. Frequently, people who know him by reputation only, are surprised to discover that he still has all of his limbs when they're introduced to him in person. Given the molecules he's worked with over the years, quite a few people are surprised to learn that it's possible to hold a conversation with him without using a ouija board.

You know you're dealing with a very special individual, when he tells people that some of his pet molecules are capable of propelling parts of your window through the air at eight kilometres per second. Yes, you read that correctly.
Logged

Remember: if the world's bees disappear, we become extinct with them ...
TRex
Glossologian
**
Posts: 1273


~50 miles from Chicago, in the Corn (maize) Belt


View Profile
« Reply #7 on: September 08, 2017, 08:39:20 AM »

I was surprised the Wikipedia article on Thomas M. Klapötke was so brief.
Logged
Calilasseia
Lexicomane
***
Posts: 137


Pass the dissection kit ...


View Profile
« Reply #8 on: September 09, 2017, 04:40:16 PM »

I was surprised the Wikipedia article on Thomas M. Klapötke was so brief.

Especially in the light of the fact that he works with substances that are headline grabbers, every time he and his laboratory group publish yet another paper in JACS or Angewandte Chemie. Such as selenium tetraazide. Which is a really attractive looking lemon-yellow solid at temperatures of -80°C or below. If you're wondering why it's kept refrigerated at such temperatures after it's made, this might have something to do with its tendency to go "bang" the moment it warms up. And by "warms up", I mean reaches -64°C. This stuff simply won't hold together at room temperature, so you can imagine synthesising it requires a fair amount of ingenuity.

Though he's also introduced the world to a new and simpler method of making other metal azide compounds, courtesy of a reaction with silver azide in ammonia. Just one slight fly in the ointment exists here, and that centres upon the fact that you have to make silver azide first. Which isn't difficult, but silver compounds have interesting behaviours. A good many of them will decompose upon exposure to light. Indeed, this tendency was the basis of the photographic film industry for many years, which used silver bromide as the photographic medium in film. The essential process allowing silver bromide (or other silver halides) to be used in film, can be traced all the way back to Fox Talbot in the 19th century, who hit upon the idea of the photographic negative, and developing the negative, which, when developed and fixed, can then be used to produce lots of prints. The sometimes hilarious history of this (not to mention Fox Talbot's ruthlessness with respect to patents) deserves a thread of its own.

However, that tendency of silver compounds to decompose when exposed to light, makes the business of making silver azide a touchy one. It means that essential steps in the Klapötke method of synthesising other metal azides have to be conducted in total darkness. Which adds to the hazards of dealing with substances that already possess varying degrees of both toxicity and explosive instability. Azides have a habit of disrupting the functions of a range of important metabolic enzymes, though this feature has pharmaceutical applications - target an enzyme that is over-expressed in cancer cells, for example, and design a molecule that homes in on those cancer cells to deliver an azide group and shut them down, and you have a pretty useful weapon in the therapeutic arsenal. Additionally, bonding an azide group to a big molecule with specificity of action, also tends to stabilise the entire ensemble, which means that your new drug isn't going to behave like TNT. You can imagine that medical safety authorities are not keen on exploding drugs, though nitroglycerine continues to be a useful vasodilator for angina pectoris - keep it dilute in the right solvent, and it'll behave itself, which handily lends itself to medical use, because you only need tiny doses to be effective.

But, that toxic capability means that even azides that behave themselves on the explosion front, have to be handled with care. Trouble is, some of them also require you to dress up like a Star Wars stormtrooper in personal protective equipment, to keep you from being unduly affected by the inevitable shrapnel. You know you're dealing with chemical hilarity when a German news article on Klapötke's work uses words such as "Bombenstoff". Cheesy

It's interesting to note that another group of readily detonating compounds - the tetrazoles - also finds uses in the pharmaceutical industry (see, for example, angiotensin II receptor blockers). Though again, they're attached to large molecules that stabilise the entire ensemble. Which adds a certain new aura to the Monty Python sketch about the quack doctor who used TNT to treat athlete's foot. I suspect that some other lively molecules find themselves pressed into medical service via convoluted routes, but azides and tetrazoles are two of the more, shall we say, touchy classes of compound that have surprising therapeutic applications. AZT, the anti-HIV drug developed back in the 1980s, is merely one of many such applications.
Logged

Remember: if the world's bees disappear, we become extinct with them ...
Pages: [1]
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2006, Simple Machines Valid XHTML 1.0! Valid CSS!
Page created in 0.044 seconds with 20 queries.