HF on Mars

[thechemist]

I thought it is time to discuss the recent announcement by Formisano et al. that ppm concentrations of HF exist on the Martian atmosphere.<br /><br />I start with some relevant HF data for Venus and Earth.<br />I'll keep searching and post if I find more specific info.<br /><br />The following is a quotation from :<br />"Longevity of fluorine-bearing tremolite on Venus" <br />by Natasha M. Johnson, and Bruce Fegley, Jr. <br />Icarus <br />Volume 165, Issue 2 , October 2003, Pages 340-348 <br /><br />link (won't work for everyone).<br /><br /><font color="yellow">"Hydrogen fluoride (HF) gas was discovered in Venus' atmosphere by [Connes et al., 1967] and determined to exist in trace amounts above and below the clouds at approximately 5 parts per billion by volume [Connes et al., 1967 and Bézard et al., 1990]. <br />By comparison, the average abundance of HF in Earth's troposphere is significantly smaller at 27±14 parts per trillion by volume [Sen et al., 1995]. <br /><br />Thermochemical equilibrium models predict that Venus and Earth contain similar inventories of fluorine [Fegley and Lewis, 1980] and calculations suggest that there is still a considerable amount of fluorine within the Venusian surface [Fegley and Treiman, 1992]. <br />On Earth, the sources for tropospheric HF are volcanic emissions and influxes of HF from the stratosphere due to photolysis of anthropogenic chlorofluorocarbons. The residence time of HF in Earth's troposphere is very short, approximately 5.5 days (calculations following [Warneck, 1988]), because HF is soluble and is removed by precipitation. <br />The sources for fluorine in Venus' atmosphere also include volcanic eruptions but fluorine (as HF) in Venus' atmosphere is most likely a direct result of Venus' high surface temperature. <br />The residence time of HF in Venus' atmosphere is probably longer because of the lack of precipitation. The combination of similar abundances of H</font> <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[thechemist]

ISO finds Fluoride Molecules in Interstellar Space <br />From ESA Bulletin Nr. 92.<br />Published November 1997.<br /><br /><font color="yellow">"Using ESA's Infrared Space Observatory satellite, ISO, a team of astronomers from Germany and the United States has discovered trace amounts of hydrogen fluoride gas in the near vacuum of interstellar space. <br /><br />Although approximately one hundred different kinds of molecules have been detected in interstellar space over the past 30 years, the discovery of hydrogen fluoride marks the first time that a molecule containing fluorine has been detected in an interstellar gas cloud. <br /><br />The observations were carried within a giant cloud of interstellar gas located near the centre of the Milky Way galaxy using the Long Wavelength Spectrometer, one of four instruments on board ISO. Looking in the far-infrared region of the electromagnetic spectrum, the astronomers observed the telltale signature of absorption by trace amounts of hydrogen fluoride gas."</font>/safety_wrapper> <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[blairf]

Similar to you TheChemist I saw the abstract and immediately thought mmmm thats odd lets find out more about HF. New findings are always interesting! My random thoughts/findings<br /><br />At the level reported HF is about a quarter as common as H20 (70 vs 200 ppm). That is extraordinarily high. Is it a misprint?<br /><br />HF is an excellent solvent (dissolves pretty much all oxides) and because of this has to be stored in Teflon test-tubes!<br /><br />At 200 ppm HF is highly posinous. Another reason (like we needed one) to not take your helmet off<br /><br />HF and H20 react together to produce a highly corrosive acid. Maybe some of the micro-formations on rocks we have been seeing at MER sites is due to this?<br /><br />HF is put forward as a 'water alternative' when people are thinking about alien life. Along with ammonia and methane it is the only obvious molecule with high enough dipoles to support the complex chemistry needed for life.<br /><br />The gas liquid phase diagram for pure HF is shown here<br /><br />http://www.airliquide.com/en/business/products/gases/gasdata/images/VaporPressureGraph/Hydrogen_Fluoride_Vapor_Pressure.GIF<br /><br />Mars is 6-10 mb and c150-250 K. This implies pure HF would generate an HF cycle similar to the water cycle here on earth!<br /><br />How has this been missed before? ppm should be exceedingly detectable. Is the HF bond difficult to pick out spectroscopically?<br /><br />HF reacts with methane to form CF4. This reaction generates a lot of energy. Some have speculated that this reaction may be part of the chemistry any methanotrophs use.<br /><br />Anyone know what the phase diagram for a 4:1 mix of H20 and HF looks like? Maybe the 'lakes' people have reported are real after all.<br /><br />This introduces a whole new set of questions for those studying Martian erosional processes, atmospheric th

 

[silylene old]

HF causes rapid corrosion of many metals and glass. I wonder if any corrosion was observed on the landers/rovers? As I recall, Viking and Pathfinder experienced several episodes of frost deposition...which presumably would contain dissolved atmospheric HF. Do we have any photographic evidence of corrosion?<br /><br />On the purel speculative side, a solvent containing a lot of flouride ion could also yield some interesting non-CHON lifeforms given the very interesting and varied chemistry of flourine. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[thechemist]

Silicon tetrafluoride is formed when sand (SiO2) is exposed to HF :<br />SiO2 + 4 HF(aq) -- /> 2 H2O + SiF4(g)<br /><br />SiF4 reacts with water to give silicic acid :<br /><br />SiF4 + 4H2O -- /> 4 HF + Si(OH)4(aq). <br /><br />Silicic acid then reacts with metals to give silicates, while HF is recycled. <br />Could this explain the high HF atmospheric concentrations ?<br />Or am I missing something ? <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[JonClarke]

You can't extrapolate from a paper on HF concentrations in the atmosphere of Venus to conditions on Mars. Let's get some information of the fluorine abundance and distribution on Mars first.<br /><br />Cheers<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[thechemist]

Hi Jon,<br />The number given by Formisano for HF in the martian atmosphere is 70 +-30 ppm (see the Life on Mars thread). Atmospheric Venutian HF is in the ppb, and earth is in the ppt region.<br /><br />I was just postulating based on well known fluorine chemical reactions.<br />More experimental data will come forward, no doubt about it.<br />70 ppm is a lot !<br /> <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[rogers_buck]

HF is what the martians use in their heat ray. (-;<br />

 

[silylene old]

Some of our remover products we sell contain about 100 ppm of F- . These are products designed to removed thin crosslinked polymeric residue films from integrated circuits after plasma etch or implant. It's amazing how effective just a trace of flouride ion in the formulation can be in destroying and solubilizing otherwise intractable polymers. The removal rate is about 100 nm/min, which is just right for its application. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[thechemist]

Ok, now I'm pi$$ed off.<br />From Oliver Morton's excellent Mainlymartian blog , this is what Formisano said:<br /><br /><i> "One other thing about the abstract is that it talks about hydrogen fluoride. Formisano didn't mention it in his presentation, but when we chatted it seemed to me he was saying that he thought he had indeed spotted some. If so, it appears that that would be pretty good evidence of current igneous activity. He wouldn't talk about levels, but he did say that <font color="yellow"> there had been a misprint in the abstract, and we’re talking parts per billion not parts per million.</font></i><br /><br />A misprint !!! Oh really ? Is that all ? no !<br /><br />"He also said : <i> That abstract, he told me, is <font color="yellow">"all wrong" and "a mess"</font> That's not to say it's not the abstract that's in the abstract book for the meeting -- it is -- but he says it at no point reflected what he really wanted to say. "</i><br /><br />At this point, I officially declare that until further notice, I will give equal credibility to Formisano as Hoagland.<br /><br />I know it sounds bad, but I've had it with this guy <img src="/images/icons/frown.gif" /> <br />I see nothing scientific in the way he practices science.<br />Read Oliver's account and decide for yourself. <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[JonClarke]

I was just going to post saying a misprint was a definite possibility! 50 ppm is just ridiculous. In Formisano's defence, this is a conference abstract, these are often written in a hurry and are not peer reviewed. It is quite easy for a typo to slip through. He certainly isn't a Hoaglandite and I am sure the rough-scanned abstract on TEM web page must be an acute embarassment.<br /><br />The thing to remember is that, unlike Venus, Mars has significant water in the atmosphere. Much of the lower atmosphere is close to saturation point, which is why we get phenomena like clouds, fogs, frosts, and even snow. These would be quit efficiente at scavanging HF from the atmosphere.<br /><br />Mineralogically the likeliest sink for F in the regolith as either absorbed on clays or as fluorite - CaF2.<br /><br />Cheers<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[alokmohan]

Such speculation without data is meanigless.

 

[thechemist]

Jon,<br />I am aware of the hocus-pocus of conference abstracts.<br />However, in chemistry conferences, usually there is some raw level of peer-reviewing in the abstracts.<br />Ischia could have used some of that, at least the ppm-that-was-ppb, which<br />is <font color="yellow"> Totally Ridiculous </font>should have been avoided.<br /><br />Actually, even peer-reviewing should not be considered a magic wand that separates the good from the bad, it has its own procedural holes in some cases.<br /><br />I just think he crossed the line this time. You can't blame it on the abstracts<br />all the time and get away with it. You have to be careful and responsible.<br /><br />I expect consistency from a guy that has his instrument orbiting Mars using public EU funding. The loss of Beagle does not look that unexpected now, does it ?<br /><br />Or, maybe I'm just a jealous spectroscopist whining all the time, I don't know... <img src="/images/icons/wink.gif" /><br /><br /> <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[JonClarke]

People in glass houses shouldn't throw stones. I coedited a book once, and they got my name wrong on the cover......<br /><br />Of course you are jealous - aren't we all? <img src="/images/icons/smile.gif" /><br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[fangsheath]

I do find it odd that a person who has expressed sensitivity about making claims ON THESE VERY ISSUES, for fear of hurting his career, would let something like this happen. It is not just about ppb vs. ppm. As far as I'm concerned, if your abstract clearly states that you have found formaldehyde, you have made the claim. The word formaldehyde appears in the abstract 6 times! I don't call that a misprint. I call that sloppy. If the abstract makes claims on important issues that you want to back away from, say so during your presentation, not later over lunch. Or does he not read his own abstracts?<br /><br />Bottom line, I think the guy believes he has found formaldehyde. He wants to hedge infinitely, so that he can take the credit if the community ultimately concurs and none of the heat if it ultimately rejects his claim. Whatever, dude. <br /><br />

 

[centsworth_II]

<i>"...in chemistry conferences, usually there is some raw level of peer-reviewing in the abstracts."</i><br /><br />Forget peer review. Formisano should have reviewed the abstract <i>himself</i> and announced any correction, not waited for someone to ask him about it. <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

Proof reading your own work is not a good way of doing it. You see what should be there, not what is there.<br /><br />Oliver Morton's report seems kosher to me. Saying one thing in an abstract and then covering somewhat different ground in your presentation is not uncommon. There are many reasons for this, some are quite legitimate.<br /><br />The problem is the subject of organic gas composition in the atmosphere of Mars is so highly charged that even the slightest hint will cause a media feeding frenzy.<br /><br />If I had papers under view by Nature and Science I would be coy too!<br /><br />Cheers<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[centsworth_II]

"Proof reading your own work is not a good way of doing it."<br /><br />I was speaking specifically of the abstract, not the work in general. It seems to me that since the abstract is the first, and in many cases the only, look that many will get of a scientist's work, it would be of high priority to the scientist to get this, his work's calling card, right. This means making sure it includes details he wants, does not include details he wants withheld, and, above all, contains no errors. <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

You are right of course, it is how it should happen. But it does not always happen that way! Then you have the problem of people writing abstracts in languages other than their own.<br /><br />Cheers<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[silylene old]

It reminds me of the pre-print of C.W Chu's famous paper on the first 1-2-3 high temperature superconductor. Chu didn't trust the referees to keep the preprint confidential. So in the preprint the composition of the miracle compound wasn't the correct yttrium-barium-copper-oxide, but rather a misleading ytterbium-barium-copper-oxide. Of course the referee's preprint got unethically faxed and copied worldwide (I got a copy!). Then when Chu received the camera proofs back for his Nature article, he altered the incorrect Yb-Ba-C-O compound back to the correct Y-Ba-C-O. Meanwhile, all the earth's refined supply of Yb had been bought and the speculative price on this incorrect ingredient had soared.<br /><br />A lot of people were very upset at C.W. Chu for this. And when the Nobel committee gave the Nobel prize for the discovery of new superconducting compounds, they conspicuously left Chu's name off - despite that he was the first to discover the magical 1-2-3 compounds, and first to get a Tc above liquid N2. <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>

 

[centsworth_II]

<i>"...the problem of people writing abstracts in languages other than their own."</i> -- JonClarke<br /><br />I hadn't thought of that! I would think, though, that English would have top priority. But take that for what it's worth, coming from an 'ugly<img src="/images/icons/smile.gif" />American'. <div class="Discussion_UserSignature"> </div>

 

[centsworth_II]

Great story! But it's sad to see someone penalized for the missdeeds of others. Or should he have forseen the consequences of his deception? What a morality play! <div class="Discussion_UserSignature"> </div>

 

[JonClarke]

reminds me of a colleague who in a paper to nature about an important fossil discovery gave the wrong location because he did not want anyone else going there. Science does have a seamy side.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[thechemist]

What a great story about Chu !<br />Didn't he have patents on this though ?<br /><br />The english of italian scientists (both spoken and written) are notorius even between other Europeans, let alone americans. (no offence to SDC users from Italy intended !)<br /><br />However ppm-ppb is <b> NOT </b> english terminology, it is international !<br />And abstract correction of silly mistakes is possible, usually. <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>

 

[thechemist]

The Ischia web page currently only points to a field trip to Vesuvius.<br />The only thing I could find for this conference is the program.<br /><br />At least the abstracts should be freely available on the web.<br />The printed book of abstracts should have become obsolete nowadays.<br />Save some trees, and dissipate information <img src="/images/icons/wink.gif" /> the year is 2004.<br /><br />On a funny note:<br />Try the Italian Space Agency website.<br />The english version is "under construction" <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <em>I feel better than James Brown.</em> </div>