Talk:Uranium hexafluoride

Historical information

When was the compound originally discovered, and if the answer is in doubt what facts are known and what facts are suspected about these dates? I think this is a compound worthy of historical notes. Zaphraud 04:01, 3 June 2007 (UTC)

Statistical enrichment

• what is 'statistical enrichment'? how much energy is consumed?

Good questions. This page needs some rewriting.

I have removed By subjecting UF₆ to repeated boiling and condensing, separation of U-235 from U-238 occurs by statistical enrichment. This just isn't correct. The process of gaseous diffusion rather consists of forcing the UF₆ through a semi-permeable membrane. The writer of this probably got the idea of boiling from studying one of the processes by which heavy water is produced.

The phrase statistical enrichment means that the output of a gaseous diffusion cell is enriched and depleted streams, not separated streams. There's a little more of the lighter isotope in the enriched stream, that's all. Nearly all isotope separation technologies work like this, the possible exception (the only one I think, I may be wrong) being the mass spectrometer. So to achieve high enrichments, large cascades are necessary. Andrewa 01:31, 2 Oct 2004 (UTC)

The process you described is separate from gaseous diffusion. The process listed was a process called thermal diffusion. It is not a very good process. The United States decided not to pursue it very early on. The Japanese were using thermal diffusion on their Thorium program during WWII but had problems with it. I believe the Germans also had a thermal diffusion early on but also stopped it. As far as my research can show, only the Japanese were seriously trying to use thermal diffusion Throckmorton Guildersleeve (talk) 15:52, 25 February 2010 (UTC)

As to how much energy is consumed, I suspect that's still secret, I may be wrong here too. But the claim you sometimes see that the amount of energy required is anywhere near the amount of energy that the enriched uranium will produce is pure rubbish. France, for example, powers its enrichment plant from a cluster of four PWRs, of which only one is dedicated to the enrichment plant. This plant produces more than enough enriched uranium to supply the entire French nuclear power program. This was so even in the days they used gaseous diffusion technology. Gas centrifuge requires far less energy, although it is still a significant amount of energy. Andrewa 02:21, 2 Oct 2004 (UTC)

Energy consumed in enrichment is not secret (why would it be?), but it varies by enrichment method and the degree of enrichment. --24.147.86.187 17:06, 15 April 2007 (UTC)

Boiling point

How is it possible to have a boiling point 8° below melting point? is this an error? —Preceding unsigned comment added by 85.220.3.115 (talk • contribs)

That is actually fine. At ambient pressure the compound sublimes, that is it goes directly from solid to gaseous state. Only at higher pressures can one liquefy the gas. UF6 behaves like the more familiar dry ice. Dr Zak 15:56, 18 April 2006 (UTC)

This is still an issue because it is confusing. I'm not a chemistry weenie, but I got an NSERC grant to work in a (chemical) research laboratory while in university on the basis of my marks, so I know (or at least knew) more than the average bear about chemistry. A careful review of the properties section shows that the melting point is under pressure, but only after researching it, confirming the temperatures and converting kPa to atmospheres. Terms like sublime, 'triple point', etc would likely be unknown to the majority of lay readers. Knowing that kPa is a measure of pressure and that 151 kPa is above atmospheric pressure is surely beyond the reach of most readers. As it stands, it just looks (even to me at first glance) like a mistake that you have a melting point above the boiling point.

Personally, I am gratified at the level of detail in this article and although various aspects of a substance might be meaningless to most, things like phase diagrams are important and valuable to someone like me, so ... I am reluctant to make any change to this article because I am not familiar enough with this type of thing on Wikipedia. The probability that I do more harm than good is too high. Still, I think it would be helpful if this seemingly anomalous information was presented in a less confusing way. DeepNorth (talk) 17:39, 7 September 2019 (UTC)

SI Units

That phase diagram should be replaced with a phase diagram with SI units.

Literally came to say the same thing. At least atm of pressure and 'C which are comparative to other compounds. https://wiki.riteme.site/wiki/File:Uranium_hexafluoride_phase_diagram.svg https://commons.wikimedia.org/wiki/File:Uranium_hexafluoride_phase_diagram_ru.svg 108.180.66.167 (talk) 23:53, 28 January 2023 (UTC)

other fluorides

Should the other fluorides get their own articles? I'm not familiar with chemical species notability standards, so I have no opinion. Ojcit 16:49, 3 October 2006 (UTC)

Hazzards

When the change is made from yellow cake to UF6. Is the end product highly reactive with water?? —The preceding unsigned comment was added by 207.195.38.77 (talk) 16:40, 28 December 2006 (UTC).

To answer simply: Yes! The production and handling of uranium hexafluoride are among the most complicated parts of uranium enrichment. Physchim62 (talk) 20:13, 25 September 2007 (UTC)

Properties?

Why does its triple point makes it useful in the extraction methods? Does it keep energy costs low in heating to only 64 Celsius in some way? The article did not make it clear to me.

Secondly I removed the external link as it had no more than that it was used in separation of uranium.

Thirdly, I felt the article needed a short physical properties section, as I was looking for things like the density at different phases and temperature, and its dielectric properties. Maybe this is too detailed for this article, but in any case I could not add a new stub section without disrupting the images. Also the chemistry section seems short - how is it produced, what are typical yields of UF6 and other fluorides, non-nuclear uses? -Wikianon (talk) 21:51, 27 November 2007 (UTC)

Shape

The chembox says that it has a pseudo-octahedral coordination geometry but an octahedral molecular shape. So what is it? Is it a distorted octahedron? By how much? --Itub (talk) 12:13, 28 November 2007 (UTC)

Isotopic content

How do physical properties (triple point, boiling temperature, specific heat) depend on the isotopic content of UF6? dima (talk) 14:30, 24 March 2008 (UTC)

I don't know any numbers, but probably not much. The mp/bp of heavy water vary by about a couple of degrees C, and heavy water is 11% heavier than regular water. In the case of UF6, the difference in molecular mass is less than 1%, so the effect on the physical properties is presumably smaller. --Itub (talk) 12:30, 25 March 2008 (UTC)

Thanks, Itub. As I understand, the separation of isotopes is more complicated than extraction of ethanol from the products of fermentation. If there is no difference, then it is possible to make a perpetual motion based on the difference in the thermodynamic properties of isotops. May be you have any references to the dependence of density of saturated vapor on the isotipic content in vicinity of the triple point? It looks strange that so basic properties are not developed... dima (talk) 03:40, 13 April 2008 (UTC)

Reduction of (NH₄)₂U₂O₇ to UO₂

Quote:
"Milled uranium ore — U3O8, or "yellowcake" — is dissolved in nitric acid, yielding a solution of uranyl nitrate UO2(NO3)2. Pure uranyl nitrate is obtained by solvent extraction, then treated with ammonia to produce ammonium diuranate ("ADU", (NH4)2U2O7).
Reduction with hydrogen gives UO2"

Question:
Shouldn't that be UO₃?
U₂O₇ goes to U₂O₆ and one oxygen for the H₂O (//=UO₃)
If so, how do I get to UO₂?
Thx in advance!

Dennis Meulen (talk) 06:55, 22 January 2009 (UTC)

Application in the nuclear fuel cycle

There is a sentence fragment "enriched uranium" at the end of a paragraph. Was that supposed to go with an image or another paragraph?

"Highly Toxic"

Just from the name, it sure sounds toxic but is more information available? Is it toxic because it is highly reactive due to the fluorine or due to radioactivity of the uranium or a combination of these things?--64.134.236.69 (talk) 03:31, 17 August 2014 (UTC)--Jrm2007 (talk) 03:32, 17 August 2014 (UTC)

If the second sentence of the article wasn't descriptive enough, I think the MSDS is a safe guide here.

"Uranium hexafluoride is a volatile white solid that reacts with water, releasing corrosive hydrofluoric acid." For example, getting it in your eyes or swallowing it would expose your tissues to HF. This is... really bad.

https://www.energy.gov/sites/prod/files/2020/11/f80/SDS-Uranium_Hexafluoride_UF6_2020.pdf

OSHA Hazards: Highly toxic by inhalation, Highly toxic by ingestion. Corrosive.

Target Organs: Kidney, Liver, Lungs, Brain, Skin, Eyes.

H314 Causes severe skin burns and eye damage

May be fatal if inhaled. May cause blood disorders. May cause convulsions. May damage kidneys. May affect the central nervous system. May cause adverse reproductive effects. May affect respiration. May cause eye damage. May affect the liver. May cause burns. May react with water.

Poison. Do not breathe fumes. Do not get in eyes, on skin, or on clothing. Do not allow water to get in container. Keep container tightly closed. Wash thoroughly after handling. Use only with adequate ventilation. Handle with caution.

The fact that this will generate radioactive decay over time is awful. There are lots of fertile isotopes in your body. For example DNA has a phosphate backbone which gives it its structure. Phosphorus only has 1 stable isotope, 31P, and will absorb a neutron to become 32P. 32P only has a half-life of 13d and will decay into sulfur, 32S. I think it's safe to say that Sulfur has different chemistry than phosphorus and wouldn't maintain the same bonds as P and your DNA will be damaged. So, ingesting something that is going to unpredictably lead to chronic DNA damage? Really bad... and this is completely ignoring the beta emission of the phosphorus to sulfur decay. 108.180.66.167 (talk) 00:03, 29 January 2023 (UTC)

Assessment comment

The comment(s) below were originally left at Talk:Uranium hexafluoride/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

Needs more chemistry info. Wim van Dorst (Talk) 23:18, 10 February 2007 (UTC). Yellowcake is not the uranium octaoxide U3O8 ! The yellow cake is the ammonium diuranate. —Preceding unsigned comment added by 92.81.80.71 (talk) 17:30, 4 May 2009 (UTC)

Last edited at 17:32, 4 May 2009 (UTC). Substituted at 09:43, 30 April 2016 (UTC)

3D model

Can’t open 3D model(JSmol) of Uranium hexafluoride. —Codenstory (talk) 05:58, 25 September 2019 (UTC)

Decimal comma

English Wikipedia uses a decimal point instead of the decimal comma shown in File:Uranium hexafluoride dimensions.svg. -- Beland (talk) 23:49, 2 March 2021 (UTC)