Talk:Heavy water

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[edit] Nuclear Proliferation

It seems to me that this section is not about heavy water so I have removed it. South Korea also possesses graphite-moderated reactors, as used by the United States, the United Kingdom, the USSR and France for their bomb programs (in fact it was stated in British Parliament that one of these had been built to the declassified blueprints for Calder Hall). A major part of the negotiations involving North Korean nuclear reactors have been to attempt to shut down all of these reactors. Dabbler 15:39, 22 Dec 2004 (UTC)

[edit] Abundance

Would someone care to explain this to me?

About one in 6000 hydrogen atoms is deuterium. (The nuclide table at http://atom.kaeri.re.kr/ton/ confirms this.) Under the assumption that the deuterium atoms are randomly distributed over the water molecules, one would expect about 1 in 6000 water molecules to be semiheavy (DHO), only 1 in about 36000000 heavy (D2O), and the rest light (H2O).

Yet the article states that heavy water occurs naturally in regular water at a proportion of roughly one part in 6,000. What's going on here? Are they trying to sell us semiheavy water as 'heavy' water? Or what?

–Herbee 2004-02-08


If 0.015% (nearer 1 in 6500) of H's are D's, then about 2 in 6500 (0.03%) of water molecules should have one D - i.e. be "Semi-Heavy" - not 1 in 6500 [1/6500 * 6499/6500 + 6499/6500 * 1/6500 = 1/3250.5]. As you say, 1 in 65002 or about 1 in 42 million should have two Ds, and be "Heavy".

Of course, the heaviest natural water is not ordinary D2O, but D218O, which weighs 22. The abundance should be 1/6500.1/6500.1/500 = about 1 in 21 billion. Not so low really; there's about a million trillion in the average glass of water...

–220.237.78.234 2004-11-29

[edit] Toxicity

Next time I want to kill someone I'll make a note of this article. Seriously, maybe that excerpt is best left out.. If there has ever been a case of this, it would be nice to note, but suggesting it as a good way to poison someone may be a bit...non-encyclopediatic? - Reboot

It does not seem to be of great scientific interest. Perhaps it is useful to writers of fiction?

Heavy water would be an ideal poison for killing someone, since it is extremely unusual for forensic tests for it to be performed, and it would appear that the person was merely suffering from some mysterious illness. However, it is very expensive, and requires a government license to purchase, making this method of killing someone less attractive in practice.

I'm not sure that this would even be true. It would seem to me that some of the standard tests that would be used in case of unknown poisoning would have sufficiently odd results that would raise a lot of suspicions. An MRI would be almost totally blank - it's an NMR scan of the body, and D2O is used as a solvent in NMR because it doesn't show up, at all.

You would think this, but if forensics ran a mass spectrum to look for other toxins then the excess of deuterium would be blindingly obvious.
Blindingly obviously, how? Toxin mass spec only comes after HPLC or GC, and if the person has no "toxins" in them (drugs, etc) then all you're looking at is the standards you added. Nada. I have no idea if forensic tox mass spec uses any internal metabolite standards, but even that ought to be difficult to see with D. For one thing, D only exchanges with OH and NH2 hydrogens, and even then you're only going to get less than 50% exchange in what is probably a fairly high MW molecule. My bet is any low intensity double lines in a calibration metabolite would get ignored, because it's not in the toxin area of interest.
(On a different note, D2O does show up on NMR, just not on the region shown in proton NMR spectra) Gingekerr 20:18, 28 May 2006 (UTC)
That's basicly noted in the article, which doesn't say there's no signal, just that the signal isn't in the protium frequency. It's even a bit more clear in the deuterium wikiSbharris 21:13, 28 May 2006 (UTC)
And I thought the stuff was sufficiently radioactive that it would poison those around it without actually drinking it... Anyone have a clue on that? I agree that if someone came into a hospital suffering from what looked like radiation poison that I'd like to think it would warrant further investigation other than "oh well he must have died from some mysterious illness...sigh....too bad...oh well, throw em in the box" -- Reboot
Pure heavy water is not radioactive, but I guess it becomes contaminated by radioactive decay products after it's been in a nuclear reactor. You're probably thinking of tritiated water (see tritium). -- Heron
In that case... Drink up :-) - Reboot

Hmmm. It seems to me that the suggestion that heavy water is toxic is a bit suspect. The ill effects are only felt if you drink nothing else. So long as you maintain a normal intake of ordinary, light water, you'll never be in danger of these supposed ill effects.

I say supposed because I doubt anyone has ever suffered them. Quite apart from the licensing aspects, last time I checked it was about 7 times the price of good whisky.

We don't regard nitrogen as toxic. But, if you breath nothing but nitrogen, you will die quite quickly. So similarly, we should not regard heavy water as toxic just because it won't sustain life in the same way that normal water will.

The same goes for Helium or Hydrogen. Neither is toxic. But breathing either of them will kill you.

Or am I missing something here? Andrewa 10:31 Mar 5, 2003 (UTC)

OK, with some foreboding I've had a go. Is this an unbiased discussion of the toxicity claims now, do you think? I've also added some other information. Andrewa 16:11 Mar 6, 2003 (UTC)

Hmmm. My comparison of the toxicity of Nitrogen to that of Heavy Water has been deleted from the article as an "improper" comparison, according to the summary: "(Deleted improper comparison: It was not said that one would die if started to use only pure D20. However if someone would die if s/he would breath only Nitrogen or Helium.)"

I think this editor has misunderstood the logic. No, nobody would die of drinking heavy water, or not quickly anyway. SO, it is even more ridiculous to suggest that heavy water is toxic than it would be to say that nitrogen (or hydrogen or helium) is toxic. QED.

So the comparison is relevant. I'm not sure how to decide whether it is "proper", but I found it helpful, and I think this deletion has pointlessly reduced the content of the article, even if only slightly. But obviously it could have been better expressed. I'll have a go sometime, unless someone else does first or successfully argues that it's not helpful content anyway. Andrewa 01:15 20 Jun 2003 (UTC)

Reinstated the comparison, hopefully more clearly. I think it's NPOV, but I admit it's very difficult to be so when the claims of toxicity are plainly ridiculous and politically motivated.

I think what the article says is still very gentle really! Andrewa 16:45 29 Jun 2003 (UTC)

I see the point... that is, while that poison... smells like almonds... can't think of name... cyanide! Cyanide is toxic; i.e. if you eat it, along with drinking like 10 cups of water, you'll still die. Whereas, if you drink some heavy water, but make sure to continue normally drinking light water, you'll be fine. ugen64 23:54, Nov 19, 2003 (UTC)

I agree with Andrewa, the comparison is a good one, I found it insightful. Pdbailey 16:55, 6 Nov 2004 (UTC)

To take it further - tap water will kill you if you fall in a bath of it and can't swim but is it toxic?.........Ordinary table salt is genuinely toxic - the lethal dose is about 2 Kg - but that doesn't stop us swimming in water, and putting salt on our food.

Any way, my question is, why did they have a heavy wter plant anyway - no-one had thought of building a bomb at the time, so what was the point of making heavy water - does it have other uses? David.andrews@wessexwater.co.uk

How universally true is it that eukaroytes don't thrive in D2O, as stated? I once left a Kleenex soaked in D2O and left it sealed in a plastic bottle to keep a D2O vapour over something. After a month or so it went black with something that looked suspiciously like pin mould, which being a fungi would be eukaryotic.Judge Nutmeg 05:14, 28 January 2007 (UTC)

Your observation may be a new scientific observation, but likely not. So far only bacteria have been reported grown in pure heavy water. I presume fungi have mitotic apparatus which would be screwed by the stuff, or they may be able to get enough normal water out of the air in the conditions you describe (even 30% normal H is enough to allow some simple eucaryotes to survive). Overall, I think the statement as it stands is likely to be correct. SBHarris 06:26, 28 January 2007 (UTC)

[edit] Norwegian infiltrators.

I heard on The History Channel it was a 7 man team not 12, does anyone know which is correct? Also they said one of the members of the team that stayed in Norway destroyed the ferry that was carry the heavy water on orders by the British (so techincally he wouldn't be a "partisan").

yes it was a 12 men crew, and one of the members did later on destroy the ferry.. I am not sure about his name though, I do know that due to the large number of potential civilian causualties he got the order from British top-level command.

I removed (twice) comments about computer games and a link to "sabotage". They where inappropriate in the context. Teemu Ruskeepää 13:33, 31 October 2005 (UTC)

[edit] Germany and The Bomb

I heard on a documentary that during World War II, Germany believed that the creation of large amounts of heavy water was essential to make an atomic bomb. Does anyone know more about this? If you do, it may be a good addition to this article.

I recall reading that the Germans goofed when they measured graphite, and thus rejected it as unsuitable. Don't have references. pstudier 03:12, 2004 Nov 7 (UTC)

[edit] If I ever get cancer, cheaper then chemo.

I am watching the show spoken of above on the history channel right now. I found the article to be at a high revalence to history and those interested in it.

HAHA

[edit] HDO

Surely you can isolate pure HDO from a sample using a mass spectrometer or centrifuge or similar mass discriminating device?--LukeSurl 23:12, 14 Apr 2005 (UTC)

The hydrogren atoms in water are in a state of rapid equilibrium: a hypothetical sample of pure HOD would become the equilibrium mixture in a fraction of a second. Shimmin 23:29, Apr 14, 2005 (UTC)

It is not stable. In water, a small fraction of the molecules are in the form H+ and OH-, and they change back and forth. Pure HDO would split up, and get mixed up, to form H20, D20 and HD0 according to the laws of probability. pstudier 23:37, 2005 Apr 14 (UTC)

[edit] Senseless Sentence: HDO

This part doesn't make any sense:

"Semiheavy water, HDO, also exists, although not in pure form: a sample of water of average composition HDO actually contains 50 percent HDO and 25 percent each H2O and D2O."

It says that semi water is called HDO and then it describes HDO as something composed from HDO and h20/d20. Can someone who knows what HDO is edit this?

[edit] Deuterium and Heavy Water should be merged!

Not at all. This statement is similar to claiming that hydrogen and water should be merged.

[edit] Chemically the same

I am wary of this statement.

Acegikmo1 05:12, 25 July 2005 (UTC)

Isotopes of an element are, by definition, all chemically the same.
No, not by "definition." By definition they all have the same standard chemical symbol and element name, but none of that guarantees that their chemical properties will be the same, and in fact they aren't. Of course this difference is much more pronounced with the hydrogen isotopes.
They are different only in their mass, which is a physical property, and in that some isotopes may be unstable (radioactive), which is a nuclear property. (Digressing, it might be more accurate to say 'some isotopes may be stable', since there are many elements with no stable isotopes, and I'm not aware of any element with no unstable isotopes.)
Having said that, the statement you object to is less true for (compounds involving) the isotopes of hydrogen than it is for any other element's isotopes. This is because the mass ratios among 1H, 2H, and 3H are larger than for any other element, large enough to have measurable effects on certain chemical properties, primarily reaction rates.
Nope, most of deuterium's bio effect has nothing to do with "reaction rates" if they that you mean some kind of slow diffusion due to mass. Rather, the bond strengths for O-D, C-D, and so on differ by quite a lot. That's due to the very large difference in reduced mass in the Schroedinger equation (or appropriate LCAO/MO approximations) for the bond.Sbharris 19:49, 1 May 2006 (UTC)
Down in the middle of the article where it is talking somewhat clumsily about the negative health effects of saturating an organism with heavy water, that's what it means. But this is still a slight effect in chemical terms, so I don't think the statement in the lead should be changed; it might make sense to talk about it more in the body of the article.
Zack 21:30, 25 July 2005 (UTC)

I suggest that this should be changed. If the kinetics and the rates of reaction are different, and the actual biochemical effects are different, then saying that heavy water is chemically identical to normal water is simply incorrect, and the article should not make that statement in the introduction, regardless of what detail it goes into later.

It is correct to say that they are chemically identical, because 'chemically identical' means 'the same element'. Mass-based kinetic effects are not enough to make them chemically different.
Zack
Actually in the case of deuterium, they are. And it's not "kinetics" but "energetics."
This is an oddity, but I agree that kinetics are a part of chemistry and it is not fair to say that two things are chemically the same when they have different chemistry. It's fair to say that they are chemically similar, just not the same. For emphasis, the effect can be about a factor of six on a reaction rate, this is not small in my book
Pdbailey 03:40, 26 September 2005 (UTC)
I don't know how I can make it clearer. 'Chemically identical' is defined to ignore isotopic differences.
Perhaps in common use, but not among chemists. A chemist will tell you that different bond strengths means different chemical behavior, whether different symbol or not. The pH of D2O at 25 C is 7.4, not 7.0. That's chemistry, and it's not any chemistry which has to do with kinetics. Sbharris 19:49, 1 May 2006 (UTC)
The encyclopedia needs to use chemistry terminology the same way chemists do, even when that is awkward pedagogically. We could do a better job of explaining how hydrogen is a special case, and maybe I'll even get to it sometime soon, but this particular sentence is correct as it stands.
Zack 05:35, 27 September 2005 (UTC)


The statement is incorrect. These are not merely "mass based kinetic effects." The compounds are chemically distinct. Please refer to, e.g., Pharmacological uses and perspectives of heavy water and deuterated compounds, D.J. Kushner, Alison Baker, and T.G. Dunstall, Can. J. Physiol. Pharmacol., 77(2): 79-88 (1999).

Notably, there is a table of data concerning the difference in chemical properties:

Table 1. Some physical properties of heavy and light water (from Katz 1965).

Property D2O H2O
Melting point (°C) 3.82 0.0
Boiling point (°C) 101.72 100.0
Density (20°C, g/mL) 1.1056 0.9982
Temp. of maximum density (°C) 11.6 4.0
Viscosity (20°C, centipoise) 1.25 1.005
Surface tension (25°C, dyn·cm) 71.93 71.97
Heat of fusion (cal/mol) 1,515 1,436
Heat of vaporization (cal/mol) 10,864 10,515

Also, an a pair of statements concerning chemical bonding properties:

"Living systems exposed to D2O experience at least two sets of effects. One is a “solvent isotope effect,” because of the properties of D2O itself, and especially its effects on the structure of water and macromolecules. The second is the “deuterium isotope effect” (DIE), resulting from the ability of D2O to replace H with D in biological molecules. The C–D bond is about 10 times as strong as the C–H bond and more resistant to chemical or enzymic cleavage. Compounds with C–D bonds tend to remain stable in H2O indefinitely, and such compounds have been very widely used for isotopic studies. O–D, N–D, and S–D bonds are also stronger than the corresponding protonated forms, but the D in such bonds quickly exchanges with H in H2O (Katz 1965; Thomas 1971)."

Since light water and heavy water have distinctly different physical and chemical properties, and react with other compounds to produce compounds that have different physical and chemical properties, it is incorrect to claim that the substances are chemically the same. "Isotopes of an element are, by definition, all chemically the same" is true, if it is true at all, only when you are discussing elements and not compounds containing those elements. Heavy water is not an isotope of water.

DrWitty 00:51, 12 November 2005 (UTC)

Most sources I have seen put the boiling point closer to 101.4 including two of the sources cited in this article. --Phoenix Hacker 02:32, 31 March 2006 (UTC)

It all depends on what you mean by "chemically identical". D and H certainly have measurably different kinetics for many reactions, but there are thermodynamic differences too. In most cases the differences are small, for instance a phase boundary may move by a few degrees C, however in some cases the difference is large. There is a term "strong isotope effect" for the latter: in some cases you can have completely different phases that are thermodynamically stable for deuterated phases than those observed for non-deuterated phases. Of course, it is possible that the phase boundaries are just shifted below 0 Kelvin or moved around in pressure, so you don't see them at ambient pressure. But this itself is an interesting topic which is probably worthy of its own Wikipedia page.Judge Nutmeg 05:10, 28 January 2007 (UTC)

[edit] Israel and Heavy Water

I removed the section on Israel. The question where Israel got its heavy water to run the Dimona reactor on is better placed in an article like Israeli Nuclear Program and has nothing to do with the use or production the compound itself. Besides, it's lifted word-by-word from the Guardian. Pilatus 15:02, 10 August 2005 (UTC)

[edit] question extracted from article

This text was inserted by an anonymous contributor in the middle of the Norway section. I've removed it from the article. Their text is in parentheses - everything else is context. Zack 19:26, 29 September 2005 (UTC)

In 1934, Norsk Hydro built the first commercial heavy water plant - (was it a heavy water plant, or in fact a hydrogen plant that made heavy water as a by product? What was the point of heavy water before the atom bomb?)
How else could they make heavy beer?

[edit] Clarification regarding pH 14

Partially refined heavy water recovered from the wreck of the M/F Hydro contained potassium hydroxide. Hydroxide was used in the electrolytic refinement process to increase conductivity. —Ryanrs 05:40, 9 March 2006 (UTC)

Yep. The actual pH (pD) of pure heavy water is 7.41. This has been fixed. Sbharris 19:49, 1 May 2006 (UTC)

[edit] Trinity link

The 'Trinity' link in the Neutron moderator section leads to the page on the religious Trinity; this would be improved if it led instead to the 'Trinity (disambiguation)' page, or better yet, to the 'Trinity test' page. Dragonbones 08:56, 17 May 2006 (UTC)

Fixed. But be bold and feel free to fix such stuff yourself, when you find it! I merely replaced Trinity with Trinity test, exactly as you suggested.Sbharris 15:32, 17 May 2006 (UTC)

[edit] Heavy water is not produced by a "reactor"

An Associated Press story today is mis-headlined "Iran Opens Nuclear Reactor," while the subject of the article is a heavy water production plant. This error was propagated into the Iran section of the article, which I have since corrected to "heavy water production facility" and not "reactor." Mike Doughney 02:23, 27 August 2006 (UTC)

[edit] Accidental ingestion section

I see the Point Lepreau incident (the "Incidents of accidental ingestion" section of the article) was removed without comment and then quickly revived. Does that section really belong here? The section states "this was not really an incident of heavy water poisoning" (i.e., in a chemical sense), so the section isn't really appropriate if its point is to illustrate the toxicity of heavy water. OTOH, the section also talks about how little heavy water each person consumed (well below the expected level for an observable effect), so it's also not really appropriate if its point is the relative nontoxicity of heavy water. So just what is the point here? "Someone did something that isn't expected to be dangerous and nothing really bad happened" doesn't seem worthy of being in an encyclopedia. DMacks 21:46, 7 September 2006 (UTC)

I wasn't involved in this section's creation, deletion or restoration. I PRESUMED that it was left in, as a "mythbuster" section to counter what might have been reported as heavy water poisoning at the time, and which might even now turn up, in a Google search looking for the topic. Sometimes you have to mention stuff which a lot of people believe or was inaccurately reported, even if it's silly. I'll see if I can highlight that in the heading or intro sentence. SBHarris 22:10, 7 September 2006 (UTC)
Looks good. Thanks! DMacks 22:50, 7 September 2006 (UTC)

[edit] Hygroscopic

I understand that heavy water is (unexpectedly) hygroscopic, which can of course affect its purity in lab settings. This was a problem in some attempts to duplicate the cold fusion experiments. --Wfaxon 14:01, 20 October 2006 (UTC)

Is it really unexpected or substantially more hygroscopic than light water? To a quick approximation, water molecules always continually exchange between vapor and liquid, but here that causes a visible effect because it leads to scrambling of the initial vastly different isotopic compositions. DMacks 15:52, 20 October 2006 (UTC)
Please Google ("heavy water"+hygroscopic) for many references confirming that D2O is hygroscopic. E.g.,
http://physchem.ox.ac.uk/msds/DE/deuterium_oxide.html
http://links.jstor.org/sici?sici=0080-4630(19370401)159%3A898%3C410%3ATNIASO%3E2.0.CO%3B2-Z
By-the-by, just because some fact is unexpected to me doesn't mean it would be unexpected to someone more knowledgable. I just thought this fact should be mentioned in this article. --Wfaxon 08:52, 21 October 2006 (UTC)
Right. I'm certainly not denying that it's hygroscopic in practice...I've had to throw away a lot of heavy water that has gotten contaminated. DMacks 07:28, 23 October 2006 (UTC)
Yes this label of hygroscopic is interesting but confusing. As stated by Dmacks, it is simply a fact of exhange of "water" molecules where your precious heavy water liquid is attempting to come into isotopic equilibrium with the light water vapour in the air. By this definition, light water could also come with a label "hygroscopic" since it is constantly exchanging with air. The only difference is that you would have great difficulty in seeing this. Perrier should come with a "warning: hygroscopic" label.Judge Nutmeg 04:56, 28 January 2007 (UTC)
Agreed. I don't think there's anything special about how well D2O sucks water out of the air compared with normal water. It's just that for D2O, you notice it. SBHarris 06:28, 28 January 2007 (UTC)
"I've had to throw away a lot of heavy water that has gotten contaminated." "It's just that for D2O, you notice it." The fact has been noted by several researchers and is included in data tables for D20. I believe this fact is sufficiently important to include in this article. How about this:
Researchers have noted that heavy water is very hygroscopic, that is, it absorbs regular (light) water from the atmosphere, being reduced in purity thereby. But the literature is unclear as to whether this is true absorption of atmospheric water or just normal molecular exchange of the liquid (heavy) water with atmospheric (light) water.
You can perhaps make that a little less awkward, but you get the point. (Hmmm, there is no Wikipedia entry for molecular exchange...) --Wfaxon 08:22, 17 February 2007 (UTC)

[edit] Bombing of the Norsk Hydro

In a PBS documentary about the Norsk Hydro Plant and the attempts to sabotage it, it was stated that, on 16 November 1943, Allied forces did drop over 400 bombs, but failed to do enough damage to the heavy water production facilities to halt production. Many other buildings were damaged or destroyed, but heavy water production continued. Has anyone else seen this documentary?

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