Talk:Hydrofluoric acid

The Talk page is not a discussion forum

So stop asking questions and discussing the properties of HF here.61.14.175.114 (talk) 07:41, 24 July 2015 (UTC)

In the environment?

Certain industries emit large amounts of HF. When HF enters the environment and gets disolved, what happens to the hydrofluoric acid? Will the F- just bind to calcium in a stream? 206.170.183.60 16:14, 18 June 2007 (UTC)

There is no simple answer to this question, plus the answer changes depending on the exact chemistry of the river/stream/sea.61.14.175.114 (talk) 07:35, 24 July 2015 (UTC)

Could someone explain why it is so corrosive?

I think we should add a section why HF, despite having such a low dissociation constant, is so corrosive. If the hydronium ions and fluoride ions are all latched together, how come it can react and dissolve all metals except iridium? (according to the strong acid page)
Kr5t 05:46, 6 March 2007 (UTC)

Sorry but there are many other metals which HF will not dissolve. I hope people do not take statements from the talk page serously! —Preceding unsigned comment added by 199.64.0.252 (talk) 09:16, 24 May 2008 (UTC)

I think Hydroflouric acid is so reactive despite its dissociation constant is primarily because of Flourine's extreme electronegativity.
~Xdorsih 23:02, 11 July 2009

Some people think acid can not melt glass

What he said.^ As many of you already know, fluorine is the most electronegative element with an EN close to 4, whereas hydrogen has only an EN of about 2.2. One general rule of thumb about WEAK and STRONG acids is that the weak and strong tag have NO bearing on its corrosiveness, strength of acidity is simply a measure of H+ DISSOCIATION not corrosiveness, which is an easy mistake to make. This acid is corrosive because of the hydrogen bonding/the enormous differences in electronegativity where the H+ and F- sort of work as a team to eat through (most) anything in their path.The reason they do not dissociate is because of the strong hydrogen bonds between the H and F that form (that no other halide has the capability of forming). If there are any chemistry enthusiasts out there who see a mistake in any of what I just said, let me know. I know a decent amount of chem but I'm no expert. Aglo123 (talk) 16:42, 28 May 2013 (UTC)

^Most of what has been said above by Aglo123 is true, but it's a bit vague. Basically, acidity is the measure of dissociation in aqueous solution. HF only weakly dissociates in water because the hydrogen bonds that form between hydrogen and fluorine are stronger than the hydrogen bonds between hydrogen and oxygen (which is what we see in the aqueous solution/water), due to there being a larger difference in electronegativities; i.e. the hydrogen bonds are shorter because fluorine is more electron withdrawing and thus strengthens the bond (intermolecular force). Corrosion works by the acid-base catalysis of the hydrolysis esters and amides. For example, our skin exists as an amide, and because of HF's stronger hydrogen bonds, it is a stronger (better) catalyst than hydrochloric acid, for example. That's why HF is so corrosive, but yet is classed as a weak acid. Remember, strength of acidity is not related to corrosive power, purely to how much it dissociates in water. Hope this helps. — Preceding unsigned comment added by 176.24.45.6 (talk) 11:28, 30 April 2014 (UTC)

Fluorspar

This page erroneously describes "feldspar" as calcium flouride. The correct word is "fluorspar." "Feldspar" refers specifically to silicates of aluminum.

Acid Constants

It'd be nice to have some data on acid constants in all of the pages on acids, really. But I'm afraid I don't have that data.

• This data is coming, at least to those acids covered by WikiProject Chemicals (which includes HF). From memory, the pK_a for HF is about 5. Physchim62 20:57, 29 May 2005 (UTC)

My text book has the pKa at 3.14. Why are there these discrepancies? — Preceding unsigned comment added by 96.245.231.88 (talk) 02:57, 1 November 2012 (UTC)

3.17 and 3.14 are extremely close on a log scale. Blame differences in experimental procedure. Aglo123 (talk) 16:50, 28 May 2013 (UTC)

hydroflouric acid

Should hydroflouric acid be a misspelling rediret - it's quite common on Google (185 000) and I'm here because I wikified it on Erich Bagge and had to change the spelling that had been used there. Richard Taylor 13:30, 18 August 2005 (UTC)

Done. --Delirium 06:13, August 30, 2005 (UTC)

Potato Chips

There are also food applications for Hydrofluoric acid, including as a potato chip flavouring where it is useful as it can give the acidic flavor required in salt and vinegar potato chips without requiring a volume of liquid which would make the crisps soggy. Hydrofluoric acid is not used for this purpose in all of today's potato chips.

eating hydrofluoric acid?! is this for real?

No, vandalism. Sodium acetate is the compound most usually used for this effect, althouth there are others. Physchim62 (talk) 13:28, 6 April 2006 (UTC)

Hydrofluoric acid (data page)

Please see Talk:Hydrofluoric acid (data page)

Dear readers, I am here to say that what you had just read about hydrofluoric acid is a lie. My fellow friends edited the whole information on the subject on hydrofluoric acid.

I repeat don't believe the info that you just read on hydrofluoric acid.

Correct properties

The page fairly states the properties of hydrofluoric acid as an encyclopedia entry.

Socksysquirrel 00:10, 11 April 2007 (UTC)

Hydrofluoric acid (Reaction)

I am a university student from Malaysia, doing a research on how will hydrofluoric acid react with hydrogen peroxide? What will be the product? Is it dangerous? Thank you!

Nasty Stuff

People, it is best to keep clear of this acid. it is insane. Once saw a lab tech get some on his hand and he was screaming for it to be cut off because it hurt so much. they had to remove a chunk of his hand just to get the hydrofluric acid off. Its best left on the shelf guys.

Just be careful. Use it in small quantities in negative-pressure apparati.

I'd say if you don't have a REASON to be using it you shouldn't be. Like uranium. —The preceding unsigned comment was added by 74.104.1.193 (talk) 04:14, 11 December 2006 (UTC).

The more I learn about HF, the more boggled I am that when I mentored kids in high school (under the guidance of the chemistry teacher!) we etched glass every year. She did warn us all about the dangers of HF (so I assume it was in the etching paste), but given that there were a few craft knife injuries every year, it's just lucky there weren't any problems with the etching paste. -Mel —The preceding unsigned comment was added by 67.135.131.194 (talk) 01:54, 18 April 2007 (UTC).

I used HF for many years in semiconductor facilities. You follow the usual precautions: use a fume hood, wear eye protection and gloves, and proceed carefully. It was not unusual to get a drop or two on the skin; you simply wash it off immediately. One of the risks is if your glove has a hole in it. HF does not burn immediately like sulfuric, nitric, or hydrochloric acid does, so the damage is done before you know it. Stop and remove your glove if you have any suspicion! Some of the older, more careless techs had undercut and even missing fingernails from handling HF without protection. I remember a war story about a guy who spent the night with his hand in a bucket of water trying to relieve the pain. That link about how people are using HF in car washes describes some insane procedures. I've added a paragraph about cardiac risk since it's generally unappreciated that a rather small spill (typically to the legs) can cause death due to cardiac arrythmia. Leg and trunk exposure is a particular problem since some people don't want to disrobe immediately with other people around. One time I was reading the label on a gallon bottle of glacial acetic acid when the bottom fell out (it must have been cracked) and the whole gallon went on my crotch and legs. I stripped off real fast, including underwear, rinsed thoroughly, and no lasting damage occurred. Modesty be damned. A friend had a similar experience with a bottle of fuming nitric acid and watched as his jeans front peeled off and dropped to the ground, taking most of the acid with them. He had some burns, but also rinsed right away. The problem with HF is it's silent but deadly. At least, the poly bottles don't fall apart.--Kbk (talk) 19:25, 9 December 2007 (UTC)

The MSDS explain the hazards associated with HF more convincingly than any testamonials and the MSDS is a verifiable source of information, which is an expectation of Wikipedia, whereas your (or my) encounters are what is called hearsay (sounds insulting but not intended that way). Several fluoride are similarly aggressive. Wikipedia also discourages editors from offering advice, hard as that can be for someone like you or me who has had experience with such nasty stuff as HF and many related compounds.--Smokefoot (talk) 19:43, 9 December 2007 (UTC)

HF Acid Attacking Bone matter

The danger of HF attacking bone calcium and the is a bit over stated: "Exposure to hydrofluoric acid may not be initially painful, and symptoms may not occur until several hours later, when the acid begins to react with calcium in the bones." Wrong. Even with delayed effect the throbbing pain is caused by interference with nerve conduction. You do not have pain receptors in your bones. Death due to hypocalcaemia is more of a concern than necrosis of bone tissue. Exposure to the lungs may lead to death well before any you have to worry about your bones.

"Under most circumstances, hydrofluoric acid exposure results in severe or even lethal damage to the heart, liver, kidneys, and nerves." I have had HF burns, and I know two people hospitalized with serious HF burns from anhydrous HF exposure. They are alive and well and so are their heart, liver, kidneys, and nerves. Immediate medical attention is the key factor in treating hypocalcaemia and tissue necrosis.

What is not over stated: this is nasty stuff. Don't use it unless you know what to do and have access to the appropriate first aid treatments. You need to have a very good plan for working with HF.

• I agree, I will try to have a look at the safety section and keep it to the correct tone. The real risk, as you point out, is immobilisation of serum calcium not the attack of bone tissue: this is why the recommended fist aid is calcium gluconate gel, to flood the affected area with a relatively lipid soluble source of calcium ions. Physchim62 (talk) 08:38, 7 June 2006 (UTC)

SiO2 is not "glass"

the sentance "Hydrofluoric acid is notoriously known to dissolve glass (SiO2):" is grossly misleading at best. silica does not simply = glass!

Actually this statement is true, HF is used to etch glass. My A.P. chem teacher has a piece of glass that he etched his name into with HF. You must remeber that while glass is not pure SiO₂, it is the main constitute. Thus if you dissolve the SiO₂ you are left with compounds that seem to have little or no problem dissolving in HF, effectivly dissolving the "glass." Kyanite 01:37, 26 September 2006 (UTC) Yes, quartz glass is pure SiO2 and is used widely in semiconductor manufacturing. Other glasses such as float, optical, crystal etc. will contain other components, but almost all will have varying amounts of SiO2.

SiO₂ is used as an abbreviation for glass since it's the only chemical component that's especially important. Artificial glasses have additives ("flux") to reduce melting point and reduce viscosity (Na-B compounds are common), but the chemistry of the glass, especially its reactivity with HF, is dominated by SiO₂. Natural glasses are filled with all the things that are present in any rock. Using SiO₂ as an approximation for glass will accounts for the bulk of the system, especially when the topic of interest is "what HF does". The statement should be retained, since the primary importance of HF is to break the Si-O bond, which other acids can't do (only F is appropriately electronegative). This is why HF is used so ubiquitous in geochemistry. Blueschist 18:49, 9 February 2007 (UTC)

It also dissolves boron oxides in borosilicate glasses due to the formation of HBF₄.

Socksysquirrel 01:43, 8 April 2007 (UTC)

Safe % Concentration?

Does anyone know at what % concentrations HF becomes reasonably safe to handle? 1%? 0.5%?

It is classified as Harmful (Xn) in the European Union (under Directive 67/548/EEC as amended) down to 0.1% by mass. Physchim62 (talk) 14:54, 25 October 2006 (UTC)

Dissolve plaster?

Will this dissolve plaster that is skimmed over a brick wall? If so, where can this be purchased. Hydrochloric acid doesn't seem to do much of anything. --Kalmia 08:00, 25 October 2006 (UTC)

I'm sure it would dissolve plaster, but it will also attack the brick underneath. Further, it would be astonishingly dangerous to use in large volumes over large surfaces. The personal protective equipment that you use – even stuff resistant to hydrochloric acid – is apt to be a tender snack for HF. You might try asking at the Reference Desk for suggestions on other ways to remove the plaster, though. TenOfAllTrades(talk) 14:23, 25 October 2006 (UTC)

HF is not actually very good for dissolving plaster (mostly calcium sulfate), as calcium fluoride is pretty insoluble in water. It is also, of course, ludicrously dangerous! Hydrochloric acid is what is usually used: the commercial stuff in France is 22% and works pretty well (HCl has its own safety problems, but less than HF). Physchim62 (talk) 14:48, 25 October 2006 (UTC)

Using HF to dissolve plaster is like using an eraser made of anthrax to erase a mark on the wall. That is to say, a bad idea. Kr5t 05:42, 6 March 2007 (UTC)

I still can't believe that "washing the car with HF" citation in the article. The reference reads more like some kind of complex April Fool's joke, though one printed in January. Maybe the concentrations are at borderline homeopathic levels, but the notion of washing a car with the help of HF strikes me as unable to rise above the merely stupid... mdf 18:13, 23 March 2007 (UTC)

It does appear to be true, if controversial, and it's not at exceptionally low concentrations. It's used in dry cleaning too. Glad I don't have a car... Vashti 04:55, 5 August 2007 (UTC)

The car washing application doesn't seem any harder to believe than selling HF in squeeze bottles for cleaning toilets and sinks. Do a search for MSDS containing HF, you'll be amazed where all it turns up. Jmputnam 16:47, 6 August 2007 (UTC)

Records of undocumented incidents

"records indicating the occurrence of such incidents are not well documented"

I'm intrigued. How does anybody know? -- Ianiceboy 08:12, 14 February 2007 (UTC)

Ha! Good point -- undocumented records, indeed! Perhaps they're telepathic, or on some storage medium that is hard to classify on this plane of reality. Sjb0926 (talk) 13:19, 27 December 2012 (UTC)

Acidity

I have changed this section to more fairly reflective the properties of this material. It is easy to mix up the corrosive properties of a substance with it's properties as an acid or base.

For example, ammonium bifluoride NH₄HF₂ is only weakly acidic but it is commonly used in glass etching reagents. Socksysquirrel 00:46, 8 April 2007 (UTC)

Nice edits. Why not include something about fluoroboric acid - it is probably manufactured from borax and HF. BTW, Ammonium hydrogen fluoride could use your touch.--Smokefoot 01:54, 8 April 2007 (UTC)

I recently saw a convincing paper suggesting that HF does dissociate roughly 100% in water, but the [H3O+F-] ion pair is tightly bound, and this tight ion pair accounts for its low acidity when dilute. This is summarized quite well in the Hydrogen Fluoride page (and that page references the same paper I saw), but not here. Could we perhaps update this Acidity section so that the two articles agree?--Skeletoroforange (talk) 19:59, 11 September 2015 (UTC)

Aerosol concentration limits of HF in humans

The article states that "The highest concentration of HF in air that can be tolerated by a human for 1 minute is 100 mg/m3. This causes a definite sensation of pain on the skin, a definite sour taste, and some degree of eye and respiratory irritation. If the air contains 50 mg/m3, the sour taste is apparent and there is irritation of the eyes and nose, but no pain is sensed on the skin. The concentration of 26 mg/m3 can be tolerated for several minutes, but the sour taste becomes evident after a short time, and there is mild pain in the nose and eyes." While I'm disturbed to learn this, and not sure I want to know how they found this out, this kind of data does need a citation. I'm adding the appropriate tags. -Interested2 02:56, 19 July 2007 (UTC)

Concentrations like these usually came from records of industrial accidents, whereas OEL comes from animal testing. 61.14.175.114 (talk) 07:15, 24 July 2015 (UTC)

How is hydrofluoric acid safely stored?

Somewhere in the article, a description of how hydrofluoric acid is safely stored ought to be included. Obviously, as it etches glass, it isn't safe in a glass bottle. —Preceding unsigned comment added by Pgranzeau (talk • contribs) 20:07, 14 October 2007 (UTC)

It's mentioned right up front. "Because of its high reactivity toward glass, hydrofluoric acid is typically stored in polyethylene or Teflon containers." -- Cyrius|✎ 02:41, 30 October 2007 (UTC)

No. I never get a Teflon Container for it. It's just PP (i'm not sure, but I think HF even reacts with Teflon) --87.162.165.47 (talk) 11:13, 25 December 2011 (UTC)

Wikipedia is not a manual or an advice column: the safety info is in the MSDS

We all want to give advice, it feels good, and with dangerous chemicals like HF, the urge is especially strong, but the necessary content is in the MSDS, which presents the pertinent information more authoritatively and more appropriately than any us could hope for. So the problem is solved, and the articles can focus on information related to the topic, not advice:

From Wikipedia:What Wikipedia is not: "Wikipedia is not a manual, guidebook, or textbook ... Wikipedia is an encyclopedic reference, not an instruction manual, guidebook or textbook.... a Wikipedia article should not read like a how-to style manual of instructions, advice (legal, medical, or otherwise) or suggestions..." --Smokefoot (talk) 18:23, 3 January 2008 (UTC)

How do you square that with what might be considered "advice" in carbon monoxide, carbon monoxide poisoning, and many of the links in poison and antidote? It doesn't seem to me that there is a consensus regarding what should and shouldn't be in the safety sections of these articles. --Kkmurray (talk) 20:17, 24 January 2008 (UTC)

Well, I can appreciate the effort to keep WP from being a how to. Just for myself, that's why I read the talk pages, to get more casual info, stories or insights that aren't in the main articles. Maybe it's not kosher writing, what have you, but I find the talk pages a very valuable way of getting more "intimate" info on topics. Just thought I'd say that - there's a place for rigid rules - that place is in the main article, IMO. Of course, all spam should be burned. Jjdon (talk) 22:33, 11 April 2012 (UTC)

In Popular Culture

should this section be here? i can't see how it's relevant or appropriate for the article, so if no one has any objections, i'm going to remove it. Coffee joe (talk) 10:50, 26 October 2008 (UTC)

look at the movie 'saw 6'. You can see the effects of HF on human body in the final scene. aergul977@hotmail.com —Preceding unsigned comment added by 88.247.150.223 (talk) 17:23, 27 December 2009 (UTC)

Appearance

What does it look like? When in dilute solution? When at 100%? Just a short description would be good. ie. "Clear blue liquid in solution, viscous pink liquid at 100%" for example. I have no idea what it looks like. Thanks, Tim. —Preceding unsigned comment added by 210.23.136.200 (talk) 10:21, 28 April 2009 (UTC)

The picture on the right shows a clear liquid, and the infobox under the picture says Appearance - Colorless solution. The next line refers to a 48% solution, which I think is the saturation concentration at 25oC. Pure HF is called hydrogen fluoride (as opposed to hydrofluoric acid which is aqueous) and has a boiling point of 19oC so it is a gas at 25oC. Dirac66 (talk) 13:58, 28 April 2009 (UTC)

Criminal Applications

In popular culture, there are references to Hydrofluoric acid being used to being used to dispose of murder victims. I'm not interested in getting back the material Coffee Joe deleted (I hate the tendency for articles to turn into collections of popular trivia), but something on the subject written by somebody with understanding of chemistry or criminalistics would add to the article. Isaac R (talk) 16:21, 25 June 2009 (UTC)

Hydrofluoric acid was used in SAW 6 in the last trap of the game. The victim was injected HFA directly into his body and it dissolved his internal organs. Andy5421 (talk) 16:06, 27 November 2009 (UTC)

HFl also features prominently in a couple episodes of Breaking Bad, although I'm starting to agree with the idea of not wanting excessive lists of trivia in articles. Titaniumlegs (talk) 08:33, 15 December 2012 (UTC)

Helpful commentary. I tend to agree that US (or any country's) TV shows should be mentioned in these articles very, very rarely.--Smokefoot (talk) 14:02, 15 December 2012 (UTC)

Trade names - Prozac and Teflon

At 04:18, 20 July 2009, Alvis replaced the trade names Prozac and Teflon by the chemical names Fluoxetine and Polytetrafluoroethylene, with the edit summary "Wiki prefers NOT using trade names when possible". I would like to ask if this policy is written in a style guide somewhere, such as a page with a name WP:something. My own opinion is that these very familiar trade names would make the article more accessible to readers who may not know the correct chemical names and not realize that we are talking about Prozac and Teflon. We could put both names with the trade name in parentheses: "Fluoxetine (Prozac)" and "Polytetrafluoroethylene (Teflon)". Dirac66 (talk) 00:44, 22 July 2009 (UTC)

Yes. Alvis is wrong. Most of the drug articles (done under the generic name) also include the trade names (which may be many). So I agree you should put them back as you propose above. SBHarris 01:51, 22 July 2009 (UTC)

There's a whole Manual of Style page about trademarks, I guess the consensus is that we can use them quite freely! We even have a featured article whose title is a trademark (Raney nickel). Physchim62 (talk) 09:35, 22 July 2009 (UTC)

Flussäure

Was “Flussäure” the old Swiss German term for “hydrofluoric acid”? --88.78.10.61 (talk) 22:48, 12 November 2009 (UTC)

Looks like it is a German name for this acid, check out [1]. --Smokefoot (talk) 00:12, 13 November 2009 (UTC)

Danger signage

I removed two danger signs from the safety section of this article. Yes, HF is dangerous, but so are many other chemical compounds. In Wikipedia Chemistry, we have not (to my knowledge) applied such signs, deferring to the signage within the "ChemBox" and the information within the MSDS, etc. This approach is codified in Wikipedia:Manual of Style (chemistry). Examples: sodium cyanide or strychnine.--Smokefoot (talk) 03:06, 8 February 2010 (UTC)

Carried Away

"although dont [sic] get too carried away with trying to stick to the 2.5% recommended, too much is better than not enough in this case." There *has* to be a better way of saying this. —Preceding unsigned comment added by 65.94.123.201 (talk) 12:07, 12 September 2010 (UTC)

picture

if someone is bored can you change it to H3O+ F-, similar to hydrochloric

It is a weak acid which does not give away the hydrogen readily, so H-F is the better image.--Stone (talk) 22:00, 25 February 2011 (UTC)

Many answers and links here

http://safety.dri.edu/Hazards/HydrofluoricAcidGuidelines.pdf —Preceding unsigned comment added by 75.4.28.190 (talk) 21:43, 25 February 2011 (UTC)

"In popular culture" addition?

It was used in the season 4 premiere of Breaking Bad (AMC show) to dissolve a body. It would be interesting to discuss if this is possible and mention other TV uses. My interest is because I am a graduate biology student and many chemistry info on the show has been accurate so far. Sometimes the media/hollywood is accurate but usually it is easily dispelled myths (like the gunfights and getting thrown back by a bullet). — Preceding unsigned comment added by 24.239.233.11 (talk) 18:13, 22 July 2011 (UTC)

It was also used in Season 1, that's why Jesse responds 'Trust us'. --201.252.211.41 (talk) 00:27, 14 August 2012 (UTC)

Safe Handling and use

I have reverted this re-addition of a large section on safety per several concerns

• Mostly unreferenced and reads a bit like a copy/paste from a manual; one ref is deadlink.
• Entirely based on Australian regulations
• Overly long for this page
• Contains some (easily fixable) problems with capitalization, spacing, formatting, etc.

This addition needs a rewrite and might suit better in a separate article (e.g. on Australian regulations in handling chemicals). Materialscientist (talk) 04:40, 16 November 2011 (UTC)

Reason for changing definite to indefinite article

The article previously described hydrofluoric acid as "the" precursor to "numerous pharmaceuticals such as fluoxetine (Prozac) and diverse materials such as PTFE". I changed "the" to "a" since this implies that you can make fluoxetine, or PTFE for that matter, using nothing but hydrofluoric acid, which is distinctly inaccurate. There are chemical reactions which have one reactant and one product; this is generally not the case for complex pharmaceuticals. A. J. Luxton (talk) 01:02, 14 June 2012 (UTC)

Precursor to what medicines?

What medicines is this used to make? Prozac is one of them. I believe a section is needed in the article that lists all medicines it is used to help create. 2602:306:C518:6C40:A59A:36CA:209E:F4D9 (talk) 20:58, 2 February 2013 (UTC)

That topic is discussed in Fluorine#Biological aspects. This material seems too tangential to be cited in the lead paragaraph that is probably why it is not developed in this article.--Smokefoot (talk) 23:52, 2 February 2013 (UTC)

source of fluoride in american water supply

you do all realize this agent is what is added to our water supply? can anyone show me one benefit from this? i see nothing but autism, cancer, school shootings, insanity, death. no other country in the world adds this HAZMAT to their drinking water... so why do we do it here? science please, show or point me in the right direction. we should all be paying more attention here it looks like our gov buys up toxic waste from other countries and gives it to us to drink? am i wrong here? — Preceding unsigned comment added by 67.251.116.164 (talk) 17:09, 29 June 2013 (UTC)

Other Wikipedia-Chemistry articles explain that (i) HF is not added to drinking water and (ii) even if it were, because of the dilute concentrations being discussed (ppm level), its chemical effects would be the same as adding sodium fluoride or hexafluorosilicic acid, which are currently added to some community drinking water supplies. We often hear complaints from unregistered editors about conspiracies, but no reliable sources for claims about autism etc. are ever provided. --Smokefoot (talk) 17:44, 29 June 2013 (UTC)

Yet the CDC explains Fluorosilicic acid is used in water fluoridation. "Fluorosilicic acid: a water-based solution used by most water fluoridation programs in the United States. Fluorosilicic acid is also referred to as hydrofluorosilicate, FSA, or HFS." http://www.cdc.gov/fluoridation/factsheets/engineering/wfadditives.htm

If this is so safe to do, why avoid mentioning it on the page for "water fluoridation" or "water fluoridation controversy". People would love to hear how hydrogen fluoride and/or hydrofluoric acid is made safe to consume and bathe in. What do you have to hide Wikipedia? — Preceding unsigned comment added by 99.61.176.89 (talk) 01:57, 6 June 2014 (UTC)

According to the Physician's Desk Reference, the mucosal lining inside the mouth has an absorption efficiency of over ninety percent. Because of this, fluoride and other contaminants can get into your blood, your brain, and your cells in no time at all. This means you can get the so-called systemic effects of fluoride simply from brushing your teeth with fluoride toothpaste or using a fluoridated mouthwash. It kind of negates the whole reasoning for putting fluoride compounds in the tap water in the first place.

The most significant flaw in fluoride research is the failure to account for the inhalation, mucosal, and dermal exposure to fluoride compounds. It invalidates all dosage conclusion based solely on ingestion. How do you think sublingual Vitamin B-12 and nitroglycerin tablets work in heart patients? — Preceding unsigned comment added by 99.61.176.89 (talk) 02:06, 6 June 2014 (UTC)

Here is the MSDS data sheet for fluorosilicic acid. Explain on the "water fluoridation" page and the "water fluoridation controversy" page what makes it so safe after it is diluted into tap water. I want to hear it. http://kcindustries.com/msds-fluorosilicic-acid/ — Preceding unsigned comment added by 99.61.176.89 (talk) 02:47, 6 June 2014 (UTC)

Have you tried the Science section of Wikipedia's Reference Desk? They specialize in answering knowledge questions there; this help desk is only for questions about using Wikipedia. For your convenience, here is the link to post a question there: click here. I hope this helps. Please note, this is not a forum for general discussion of the article's subject. Plasmic Physics (talk) 05:19, 6 June 2014 (UTC)

The only section he should be going to is tin foil central.61.14.175.114 (talk) 07:20, 24 July 2015 (UTC)

Title Picture is incorrect and misleading

The picture on the top right of the page pictures hydrofluoric acid as a mixture of entirely H₃O⁺ and F^-. Considering that HF is a WEAK acid with a pKa of about 3, that picture is completely incorrect. HF + H₂O <--> H₃O⁺ + F^- K_eq = 10^-3 (i.e. the solution is MOSTLY water and HF). This picture should be replaced. --El Zarco 22:45, 4 November 2014 (UTC) — Preceding unsigned comment added by ElZarco (talk • contribs)

Yep. Only 1 in 1000 or less is dissociated. The rest is HF. This is important in the toxicity, since F- wouldn't penetrate your skin, but HF does. Then it reacts with your calcium ions and you're dead.

I've replaced it with an HF molecule but somebody is going to want some water around it. Fine-- when they get around to drawing that, they can put it in. Meanwhile, the model you see is most correct for HF "acid." SBHarris 00:11, 5 November 2014 (UTC)

Well one has got to intake a lot of fluoride, grams of the stuff, before one is dead. This stubborn fact drives antifluoridationists nuts. I agree about HF mainly being a molecule. the idea that HF is a weak acid is complicated because of self-association: 2 HF --> H+ HF2-. I guess we could show that calculation. --Smokefoot (talk) 04:00, 5 November 2014 (UTC)

For what it's worth the HF image has been used here in the past, only to be deleted on the basis that hydrofluoric acid is different from HF. The reality is complicated, as a whole range of structures exist depending concentration (DOI:10.1021/ja01373a012). Oddly it's all explained in more detain over at hydrogen fluoride than it is here, perhaps some reorganisation might be in order? --Project Osprey (talk) 10:02, 5 November 2014 (UTC)

External links modified

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EPA Quote

I think this information from the EPA is relevant [[2]] and should stay in, please weigh in. TantraYum (talk) 01:27, 1 May 2018 (UTC)

I think you need to read that source more carefully. In particular, the difference between fluorides and hydrogen fluoride. That source does not support the claim (incorrectly) made here. Andy Dingley (talk) 01:30, 1 May 2018 (UTC)

Thanks, ok, will drop it. TantraYum (talk) 01:33, 1 May 2018 (UTC)

False statement in Lede

"By interfering with body calcium metabolism, the concentrated acid may also cause systemic toxicity and eventual cardiac arrest and fatality, after contact with as little as 160 cm2 (25 square inches) of skin."

So one femtogram spread over 161 cm² will cause cardiac arrest, but two kilograms spread over 159 cm² are fine?

Anyone wants to test that theory? 91.10.31.252 (talk) 01:34, 1 January 2019 (UTC)

You couldn't spread a femtogram over 161 cm², and 2 kilograms would cover way more than 159 cm² Tornado chaser (talk) 02:11, 1 January 2019 (UTC)

That's the best argument you have for keeping this nonsense statement in the lede? 91.10.31.252 (talk) 07:24, 1 January 2019 (UTC)

How is this statment nonsense? Tornado chaser (talk) 13:26, 1 January 2019 (UTC)

Did you even read my earlier comment? In which case the answer should be glaringly obvious: The dose it not mentioned. 91.10.46.150 (talk) 14:47, 1 January 2019 (UTC)

I agree that the statement is incomplete and doesn't make sense as written, so I have removed it for now. Toxicity via dermal contact is going to depend on the dose absorbed which in turn will depend on both the amount of material involved and the area of skin involved. -- Ed (Edgar181) 14:52, 1 January 2019 (UTC)

Duplicate section headings

Why does this article need to maintain overlapping (if not quite duplicate) sections? See [3] and [4].

This was fixed as "removed duplicate sections" (I've not checked line-by-line, but there is no evident problem with it), but then reverted "unexplained". What gives? Why should they be duplicated like this? Andy Dingley (talk) 16:26, 16 November 2019 (UTC)

Oh sorry. I acted to hastily. Let me try to repair the problem. --Smokefoot (talk) 17:09, 16 November 2019 (UTC)

Health and Safety is still duplicated in two locations, but they are only 95% the same... Looks like some edits have been made to one but not the other. In any case, one of them should be deleted. 190.98.209.18 (talk) 17:58, 2 December 2019 (UTC)

Hexafluorine treatment

This article expressed approval of the Hexafluorine product (this is a propriety solution used to treat HF burns). However, only a spam link to the manufacturer's website was cited.

I rewrote that paragraph with information on the product's effectiveness backed by a review article. I also kept the PREVOR Group's spam link to demonstrate the product is proprietary (feel free to delete if unneeded).

I only found research on Hexafluorine's use treating ocular burns. If anyone has more to add on the product, please do so (with credible sources). 35drake (talk) 14:57, 3 February 2023 (UTC)

• Can you specify the chemical nature (formula) of what the manufacturer calls "Hexafluorine"? Preferably with a reference. Dirac66 (talk) 20:43, 3 February 2023 (UTC)

HF is poisonous?

Re NaF: "the lethal dose for a 70-kg human is estimated to be 5 – 10 g of sodium fluoride". WP:TERTIARY Source: Ullmann's Encyclopedia of Industrial Chemistry. So HF is hardly toxic. That is one reason that NaF is allowed in toothpaste and bread and other foods for fluoridation. --Smokefoot (talk) 13:54, 7 April 2023 (UTC)

Sorry, are you suggesting that we shouldn't describe HF as poisonous? The problem with extrapolating from a different fluoride compound to HF is that...counterions matter. (Compare, for example, NaCl and HCl. Or BaCl versus BaSO₄.)

Gram-for-gram, it's not botulinum toxin or VX or fentanyl, certainly. But it would be inappropriate to avoid reference to its toxicity, for a few reasons.

• The nature of the product and its use in industrial settings mean that exposures tend to be in larger-than-milligram quantities.
• Because exposures are often to liquids and gels, the toxic effects on tissue are often localized to a portion of the body; considering toxicity only in the context of a whole-body LD50 understates the risk.
• The mechanism of action (local calcium ion depletion) is relatively unusual and insidious. Apparently superficial exposures can result in deep tissue damage, damage can progress relatively slowly and continue after exposure, and nerve damage can suppress the perception of injury.

So—yes, HF is poisonous, and we should continue to say so. TenOfAllTrades(talk) 14:19, 7 April 2023 (UTC)

Thanks for taking the time to discuss the matter. Sort of a gnarly topic and I agree that HF should be listed as toxic just out of sense of caution. But to get to the gnarliness, BaCl2 is toxic because of Ba++, HCl is not particularly toxic (our stomachs are loaded with it, freshman chem lab uses it a lot) but strong proton sources are corrosive. Aqueous HF is not strongly acidic but "simply" a source of F-. But I am no toxicologist, and possibly I am missing something. One reason for my obstinacy is that I contend with occasional editors who are alarmist about water fluoridation, aluminium ore processing (hexafluorosilicic acid), and related fluoride topics. Cheers, --Smokefoot (talk) 22:29, 7 April 2023 (UTC) And to pile on - mirthfully - about "counterions matter": many folk (me too) say that the oceans are loaded with sodium chloride, but there is no sodium chloride in our oceans. There are sodium ions and there are chloride ions, but they dont know about each other.--Smokefoot (talk) 22:33, 7 April 2023 (UTC)

The issue, I think, is that because HF isn't a strong acid it's not "simply" a source of F-. That's why HF can penetrate deeply into tissues (instead of 'just' burning at the surface) and causes damage (in part) by precipitating calcium (as calcium fluoride)--thereby upsetting all kinds of important calcium-ion-dependent signalling.

For what it's worth, you really don't need to be worried about me abusing sources to make outlandish claims related to water fluoridation, and that's definitely not the angle from which I'm approaching this area. (For example, my last edits to hexafluorosilicic acid were to remove confused bullshit related to water fluoridation.) TenOfAllTrades(talk) 00:44, 8 April 2023 (UTC)

I would also point out that aqueous HF is not a mixture of two effectively independent counterion species like NaCl or NaF or HCl. As pointed out near the end of the acidity section, the IR spectrum shows that HF is a weak acid because the main solute species in dilute HF is the hydrogen-bonded ion pair H₃O⁺·F⁻. So unlike NaCl, the two ions in HF do in fact interact strongly or "know about each other". Dirac66 (talk) 00:52, 8 April 2023 (UTC)

I think we should add a related chemical compounds.

In the infobox, make sure you keep consistent among the others. Thanks. 2001:EE0:4BC3:F920:B58E:E5C:90B0:54BE (talk) 05:20, 26 November 2023 (UTC)

Italicized pharmacokinetic parameters

Smokefoot, in this recent edit, you re-italicized the pharmacokinetic parameter symbols. Can you explain why you did so? In no other article I have seen are they italicized, and from my reading of PHARMMOS, they should not be italicized. Kimen8 (talk) 15:10, 1 December 2023 (UTC)

You will find that when you publish in professional journals, we italicize pK and related variables. Please avoid being dogmatic. We are here to write accessible, general encyclopedic articles.--Smokefoot (talk) 15:13, 1 December 2023 (UTC)

I know from experience that when publishing in professional journals, specific jargon and even stylistic presentation may be more or less common, and some journals will have their own enforced style guides.

Wikipedia is not a professional journal, and it has its own manual of style that may disagree with popular or official publishing guidelines of specific journals. In particular, in no other pharmaceutical article have I seen these variables italicized. It is just as accessible and general and encyclopedic whether or not it is italicized, but only one of those ways is it also consistent with other articles and with the manual of style. Consistency of presentation has value in itself (hence the existence of a manual of style), and reducing the notion of trying to keep adherence to the manual of style to being simple dogmatism is not constructive. If you want to be pedantic about accessibility and generality, consistent presentation aids in both of those.

I think the variables need to be un-italicized again. If you disagree such that you're simply going to revert, we should ping other editors to get their opinion.

Kimen8 (talk) 15:25, 1 December 2023 (UTC)

Go for it mate. Wikipedia is not a pharma venue either.--Smokefoot (talk) 15:50, 1 December 2023 (UTC)

I'm not sure what you mean by Wikipedia is not a pharma venue either.

By Go for it, do you mean you aren't going to simply revert? Or do you mean that I should get another opinion in here first?

Kimen8 (talk) 15:52, 1 December 2023 (UTC)

Italicize as per IUPAC Green Book. That is an authoritative source for chemistry (this particular article is styled as chem not pharm) and not beholden to any specific publisher. That's also consistent with the acid and other similar articles' conventions and incidentally apparently also matches the LaTeX default. I am not familiar with current medical literature publication standards. Could you link us a few that instruct to use roman-type for the K? DMacks (talk) 20:18, 1 December 2023 (UTC)

My apologies, I read too quickly on too small a screen to notice that it was the acid ionization constant K_a and not the inhibition constant K_i. Given that that and pK are within the scope of chemistry styling, I defer to the both of you on which is preferred, and I'll leave the article as is in that regard. Kimen8 (talk) 20:25, 1 December 2023 (UTC)