Talk:Hexafluorosilicic acid

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[edit] Proposed move to hexafluorosilicic acid

1) Although on some planets "Dihydrogen hexafluorosilicate" might be common, this name is rarely heard by chemists on earth.

2) Using the highly unreliable Google test: Dihydrogen hexafluorosilicate returned 850 hits, and hexafluorosilicic acid gave 16000.

I therefore propose to move this article (while it is still young and stubby) to "hexafluorosilicic acid", where it will grow deeper roots. Complaints, comments, concerns, etc?--Smokefoot 01:08, 27 January 2007 (UTC)

[edit] Safety info

Smokefoot removed properly cited safety information without comment. What is the purpose of this action? This deletion will be reverted. Petergkeyes (talk) 02:35, 26 May 2008 (UTC)

Because I felt that your contribution included a serious omission. Here's your quote: "Contains trace elements including lead and arsenic." First, obviously hexafluorosilicate contains traces of other elements - everything does. And here is the quote from the Brits "Trace elements such as lead and arsenic are present in minute quantities in fluoride compounds. But, because of the very high dilution factor, fluoridation makes no measurable contribution to the concentration of these substances in the water supplies." I also thought that your inclusion of extensive safety warnings, which exceeed the level of wording we provide to most chemicals, was (i) giving advice (see Wikipedia:What Wikipedia is not) and (ii) out of proportion. But do what you gotta do. The editors are accustomed to a high level of, shall we say, "enthusiasm" from those interested in fluoridation. --Smokefoot (talk) 02:47, 26 May 2008 (UTC)

I have cut down the safety information to a minimum. We don't give this excessive level of detail in any other chemical articles. If you want to discuss how much safety info should be in chem articles, go and post a message at WP:CHEM, but don't re-add the text unless you get consensus here.

I removed the bit of arsenic and lead, too, since there was no explanation of why this information is important. The sentence did seem to imply that the presence of these toxic metals poses a risk to people who drink water that has been treated with hexafluorosilic acid - this is not the case (concentrations too low to matter), as the reference provided points out.

Ben (talk) 22:27, 26 May 2008 (UTC)

Took a quick look at Wikiproject: Chemicals. Didn't see anything there discouraging posting safety precautions or trace elements, but please point it out if I missed something.

Ben, I don't think HFSA "treats" water. If you were on, say, dialysis, I don't imagine you would want any of your water to be "treated" with this substance.

I was responding to this plea: "This inorganic compound-related article is a stub. You can help Wikipedia by expanding it." The "Safety" section refered to another substance, but was barren of any safety precautions. I'm not clear on why posting safety precautions are being discouraged on this page. Petergkeyes (talk) 04:16, 27 May 2008 (UTC)

I said don't re-add your bit till you get the green light! I'm going to ask others to get involved.

Just because a tag says "expand", doesn't mean you can add bad content at will. Read Wikipedia:Tendentious editing.

If this safety info is going to be in the article, it should be added to the several R- and S-phrases that are already found in the chembox. This is really the only appropriate place for information of this kind. If it is going in the body of the article, re-write it in proper prose, providing appropriate references for not just the facts but their importance.

Ben (talk) 05:55, 27 May 2008 (UTC)

This statement has been shown not to be true: "Hexafluorosilic acid, like other compounds used to fluoridate drinking water, contains trace elements such as lead and arsenic. However, the dilution factor is so high that fluoridation causes no measurable increase in the concentrations of these elements in drinking water." The quote is undated, and judging by its citations, may be as old as 1993. It does not take into account the data on silicofluorides and lead that have been emerging in the past decade. I propose adding this text:

In 2001, Dr Roger Masters reported that, "taking economic, social and racial factors into account, where silicofluorides are used, children absorb more lead from the environment." ^[1] Petergkeyes (talk) 00:08, 28 May 2008 (UTC)

Might want to rephrase that to make it less emotive (children absorb lead!) but, yes, stick that in. What it does not say is that the trace amounts of Pb and As found in hexafluorosilic acid are the sources of this extra absorbed lead.

Ben (talk) 06:37, 28 May 2008 (UTC)

Um, no. Hexafluorosilic acid does not contain anything other than hydrogen, silicon and fluorine. The solutions of HSiF₆ used for fluoridation may do, but that is a matter for discussion on the fluoridation pages, not here. It's not a property of the acid, it's a property of the way the solutions are made. Why not move the comment about lead and arsenic to the fluoridation pages? Chris (talk) 08:02, 28 May 2008 (UTC)

Yeah, that's an even better proposal. But don't write "little children will die" or similar. I'm sure any toxic effect affects adults, too.

Ben (talk) 13:22, 28 May 2008 (UTC)

How's this:

H2SiF6, as used in water fluoridation, contains traces of contaminants such as lead and arsenic, but in quantities so minute that they are often undetectable. Petergkeyes (talk) 22:03, 28 May 2008 (UTC)

In fact, there's no need to mention that H₂SiF₆ solutions used in fluoridation contain traces of Pb and As because it has no consequence. Don't write it in any article - it is a (possibly) true but irrelevant fact.

Ben (talk) 22:27, 28 May 2008 (UTC)

Probably every chemical compound on the market has traces of arsenic and lead. Analytical reagent-grade sulfuric acid from Mallinckrodt Baker has up to 1 ppm Pb and 0.01 ppm As.[1] U.S. Pharmacopeia-grade sodium chloride has up to 1 ppm As and 2 ppm Pb.[2] And so on. The real question is whether such traces are relevant or not. But common sense suggests that if you take H2SiF6 with a few ppm of Pb and As, and dilute it so that you have a few ppm of fluoride, as is done for water fluoridation, you will be adding at most a few parts per trillion of Pb and As to the drinking water. That's negligible by any standard other than homeopathy. ;-) --Itub (talk) 08:24, 29 May 2008 (UTC)

Have removed this information; true, but irrelevant ;) Chris (talk) 10:10, 29 May 2008 (UTC)

Just to jump in - I think people are more likely get exposed to lead in drinking water through lead pipes than any trace impurity present in the manufacture of this compound. I agree with the above - elements Pb and As are not part of this compound, the compound only contains the elements Si, F and H. Talking about other elements is a red-herring IMO -- Quantockgoblin (talk) 12:48, 29 May 2008 (UTC)

[edit] Controversy between UK and EU

There is a substantial controversy taking place in UK and Ireland, where HFSA is used for water fluoridation, and in EU where use of HFSA failed a formal vote by the safety commission. Several anti-fluoridation groups have taken up the flag and are agitating for cessation of fluoridation in UK. Should this be referenced in this article at all? Opinions? NReitzel (talk) 15:27, 6 June 2008 (UTC)

If it should go anywhere, it should be at water fluoridation controversy. --Rifleman 82 (talk) 15:45, 6 June 2008 (UTC)