Sciencemadness Discussion Board

PBr3 -> PCl3 "New" Old Method

Sauron - 16-2-2009 at 06:47

We have previously discussed the conversion of PBr3 to red P using Hg in the manner described in the P section of Brauer, q.v.

That method is do-able butrather long, and gives a product contaminated with Hg and Br2.

Now it seems that method is superfluous, at least for the purpose of turning the P into PCl3 or PCl5.

According to Mellor, citing J.H.Gladstone, Cl2 displaces Br2 from PBr3

2 PBr3 + 3 Cl2 -> 2 PCl3 + 3 Br2

The boiling points of the trichloride and tribromide are about 100 C apart so with any sort of column, Br2 will come off first, then PCl3 at 74-78 C and any unreacted PBr3 will remain in the pot

HgCl2 also reacts to form solid HgBr2 and PCl3. This method is however unduly expensive, unless you are making your own HgCl2.

2 PBr3 + 3 HgCl2 -> 2 PCl3 + 3 HgBr2

A TEXTBOOK OF INORGANIC CHEMISTRY Vol VII Part II (1934) by Prideaux, makes the same assertion that chlorine's affinity for P is greater than that of Br or I but the author uncharacteristically does not give a lit. reference.

@Formatil, does Gmelin's vhapter on PBr3 have anything to say about this, especially literature wise?

I have a liter of PBr3, and can buy more anytime, so I am really quite interested.

The paper by Gladstone cited by Mellor is J.Chem.Soc 3, 5, (1851) which by the way was during a brief period when that journal was quarterly.

At first glance the paper concerns the reaction of sulfur with PCl5 and I have yet to find any mention of halogen exchange with PBr3. It is anyway attached. @woelen, you may find it interesting and perhaps confusing.

[Edited on 16-2-2009 by Sauron]

[Edited on 16-2-2009 by Sauron]

Attachment: qj8510300005.pdf (643kB)
This file has been downloaded 610 times

gsd - 16-2-2009 at 07:09

Passing Cl2 thru' Bromides is a general method of displacing Br by Cl.

In fact industrially, Bromine is made (recovered to be precise :)) by displacing it from the inorganic bromides dissolved in sea water concentrate (called "bittern") in a counter current contacting column.

gsd

Sauron - 16-2-2009 at 07:46

Isn't it nice to have support for a specific application?

I regard my PBr3 as too precious to chance on a guess. Reactions often stated to be general often have some fine print that a Boston lawyer would be proud of.

Case in point

3 CCl4 + AlBr3 -> 3 Cl3CBr + AlCl3.

Br ought not to displace Cl - but it does.

I would like to do the reverse, to make CCl4 from my Cl3CBr

because I can and have bought the latter but the former is prohibited. (Montreal)

I have yet to see any lit. on displacing Br with Cl in this specific instance. So much for general reactions.

[Edited on 16-2-2009 by Sauron]

Sauron - 16-2-2009 at 20:40

In a PM a member commented that Br2 liberated in this fashion will combine with unreacted PBr3 to form PBr5.

However the lit. states that Cl2 also decomposes PBr5 to PCl3 and Br2.

As the reaction proceeds, with increase of PCl3 and decrease of PBr3, free Br2 will separate as a lower layer because it is only partly miscible with PCl3. Indeed, it is reported that Br2 dropped into PCl3 falls through without reaction.

There are known bromochlorides or chlorobromides of phosphorus but these do not form at ordinary temperatures or higher. They form in the cold. See Mellor, also Prideaux.

It has also been advanced as a criticism that the bps of Br2 and PCl3 are too proximate for frationation. Bromine boils at just under 60 C and PCl3 at 74-78 C. Given that the bulk of Br2 will be removed as a separate layer and that only a minor amount will be present in the PCl3, given an efficient column I do not see why 1 or 2 distillations will not clean this up.

Nicodem - 17-2-2009 at 00:24

Quote:
Originally posted by gsd
Passing Cl2 thru' Bromides is a general method of displacing Br by Cl.

Actually, it is only general to solutions of ionic compounds, that is Cl2 oxidises the bromide ion. Such redox reactions generally does not occur on covalent compounds unless allowed by alternative mechanisms. For example, you can't "displace" Br from ethyl bromide with Cl2 and so on. The reason why it works on PBr3 is not in that Cl2 oxidises the bromide ion since there are no bromide ions in PBr3, but because Cl2 oxidises PBr3 to the transient species PBr3Cl2 which being highly unstable decomposes to Br2 and PBrCl2 and this further reacts the same way (or disproportionates) until you have only PCl3 and Br2. It is a (III)/(V) phosphorous valence thing, not a ionic redox reaction.
Similarly the reaction of CCl4 with AlBr3 that Sauron cited above is also not comparable to Cl2 redox reaction with the bromide ion (actually it is not even a redox reaction). It appears to be a simple S<sub>N</sub>1 reaction driven by the extreme acidity of AlBr3.

Sauron - 17-2-2009 at 00:53

Thanks, Nicodem, and very interesting.

How would you suggest accomplishing the replacement of Br on BrCCl3 with Cl?

Excessc AlCl3 at reflux?

Cl2 and hv? Danger here is C6Cl6 formation via the pesky trichloromethyl radical.

Or do I need to go to some more extreme chlorinating agent like (shuffer) SbCl5?

The literature is silent on this, probably because it is, on its face, unsound economically.

However, given that I am allowed neither CHCl3 not CCl3, but am allowed BrCCl3, it is a viable route for me if I can make it work.

Nicodem - 17-2-2009 at 01:31

The problem with the reverse reaction, that is 3 CCl3Br + AlCl3 <=> 3 CCl4 + AlBr3, is in that it goes against the thermodynamics (from AlCl3 a stronger acid forms, AlBr3; even though the higher thermodynamic stability of CCl4 vs. CCl3Br gives a bit of a compensation). So you end up with praising for fast kinetics and guestimation of the equilibrium constant being approximately bellow 30 which would enable you to remove CCl4 as it forms via fractionaction from the slurry of CCl3Br with a large excess of AlCl3 (and nevertheless, once too much AlBr3 forms even a fractionation column would not help to remove the ever more tiny equilibrium amount of CCl4). Though it might be very much worth a scientific experiment, I do not see it as preparative method.
In principle you can calculate the equilibrium constant since, I think, most thermodynamic parameters of the components of this reaction are known. Yet you can not calculate its kinetics - if the kinetics are too slow you can not remove CCl4 as it forms because it forms too slowly.

A photochemical homolytic cleavage of CCl3Br in a Cl2/CCl3Br solution should in principle give a Br2/CCl4 solution. The C-Br bond is more easily homolysed than C-Cl and both the CCl3* and the Br* radicals are easily oxidized with Cl2, yet I'm no expert in photochemistry so I would not put a bet on it.

Sauron - 17-2-2009 at 02:04

Yes I actually dug up papers on the UV photolysis, using special Kopp Glass filters to avoid the side reaction, and it was all done on a tiny scale for p-chem purposes, so difficult to turn into a prep process. I identified a filter superior to the one used by the authors (syill made) and discussed this on the forum.

What about the brute force option, SbCl5, that sort of thing? Still SN1 I think.

panziandi - 17-2-2009 at 05:59

I hate to keep raising my head on the CCl3Br > CCl4 topic but I have a few ideas

1) it may be possible to use a chlorinating agent such as SbCl5, or even HgCl2 AgCl based on the same reaction working with these fluorides.

2) it may be possible since the Br in this compound is reactive, to preferentially remove the Br over Cl with moist Fe to give chloroform. Ok it is not a reaction to give carbon tet but it does give you chloroform which for Sauron is impossible to purchase like carbon tet.

I have spoken to Sauron with regards these ideas and I think it is safe to say that neither of use are sure if they will work. Given the bp difference of CHCl3, CCl4 and CCl3Br I do not see why these reactions could be performed to fractionally separate the product as it forms driving the reaction forward if need be.

I do not have CCl3Br to try either of these reactions I have been proposing, but in light of Saurons post with regards the reaction between CCl4 and AlBr3, I may be able to make a small quantity of CCl3Br and give these reactions a go.

Sauron - 17-2-2009 at 09:08

Thanks. I have not forgotten your suggestions..

HgCl2 MW 271.5
HgBr2 MW 360

CCl4 MW 152

BrCCl3 MW 197

Stoichiometry

2 BrCCl3 + HgCl2 -> 2 CCl4 + HgBr2

Merck makes no mention of HgCl2 solubility in CCl4, though it is slightly sol in CS2.

The liquid phase will lose 45 g/mol, the solid white crytals gain 90 g/mol. The d of the liquid decreases sharply from 1.997 to 1.59 and the bp decreases to 76 C from 105 C C from . CCl4 can probably be stripped off during the reaction but the column will need to be efficient and the reflux ration high. I bet this will be a slow process.

The refractive index of CCl4 is 1.459 and that of BrCCl3 is 1.5055

[Edited on 18-2-2009 by Sauron]

panziandi - 17-2-2009 at 12:11

Yes Sauron the only trouble with my suggestion is the expense and also the m.w. of both AgCl and HgCl2. On a mass for moles basis it is a hideously large reaction. I will try and make some CCl3Br at somepoint and then give this a go. Both AgCl and HgCl2 are easy to make from scrap metals if this reaction was to be scaled up with reduced cost in mind.

Anyway back onto the original thread topic I think... I don't see why a couple of fractionations of the PCl3 wouldn't purify it of Br2 either. What is the solubility of Br2 in PCl3 anyway? Also we all know just how volatile Br2 is perhaps a brisk current of warm dry nitrogen could be blown through the PCl3 to remove the Br2?

Sauron - 17-2-2009 at 12:33

Better make that Ar. N2 often reacts with P compounds.

Br2 has very limited solubility or miscibility with PCl3. Added to PCl3, liquid bromine falls through and forms a bottom layer without reacting. I have not seen any quantification of the miscibility, though.

I have both HgCl2 and PBr3. So I can try this but I want to get a new pair of gauntlets for my glove box. This is going to be an Ar atmosphere job and, I do not want to make POCl3 out of my PCl3 by expositiong it to atmospheric O2.

panziandi - 17-2-2009 at 13:37

Mmm I was going to say Ar then I thought "nah N2 would do" ... really I never thought it would react with nitrogen.

Sauron - 17-2-2009 at 19:23

Hold on, you are going to do BrCCl3 to CCl4. That is fine with N2. I am talking PBr3 -> PCl3. and for that I would use Ar.

That's what I get for posting at 4 a.m.

Formatik - 18-2-2009 at 00:12

Quote:
Originally posted by Sauron @Formatik, does Gmelin's vhapter on PBr3 have anything to say about this, especially literature wise?


I had only some info from the 8th edition on the chlorides, which synthesis info was posted in the acetic anhydride thread. The 7th edition does mention that mercury chloride and PBr3 get PCl3 and mercury bromide according to Gladstone in: Phil. Mag. [3] 35, 345; J. pr. Chem. 49, 40; J.B. 1849, 243.

The Refs.: Phil. Mag. = Philosphical Magazine and Journal; J. pr. Chem. = Journal für praktische Chemie; J.B. = Jahresbericht. The prime reference should be Phil. Mag. and the J.B. likely referencing the two refs since it is similar to Centralblatt.

Basically, Gladstone from another angle. I suspect the 8th edition likely has additional references, but can't confirm it at this time.

Sauron - 18-2-2009 at 01:21

I do not know where (or if) I can lay hands on Philosophical Magazine in syberspace.

J.prakt.Chem. is another matter.

Unfortunately the free BnF archive for this journal starts 20 years too late.

But Wiley to the rescue.

Ueber die Verbindungen der Halogene mit Phosphor (p 40-51)
J. H. Gladstone
J.prakt.Chem 49, 40 (1850)-51
DOI: 10.1002/prac.18500490102

Thanks, @formatik, I am requestion this from the angels and demons of References.

For the benefit of other members: J.prakt.che, can be found at Wiley as a previous title of Advanced Synthesis & Catalysis

And from 1870 till mid 1930s it is in BnF Gallica for free.

[Edited on 18-2-2009 by Sauron]

Sauron - 18-2-2009 at 02:13

PS to above

Philosophical Magazine, started in 1798, is the flaship publication of Taylor & Caldwell who ballyhoo it as the oldest continuously published scientific journal.

However the digital archive extends back only to 1956.

This sucks'

BnF does not have it.

panziandi - 18-2-2009 at 02:47

Well yes I will try the CCl3Br if and when I get a chance to (involves making CCl3Br first from CCl4 just to see if I can then convert it back to CCl4!!!)

My post about flushing Br2 out with a current of warm gas was in relation to PBr3 > PCl3 and I never realised nitrogen would react with PCl3! Besides if the Br2 contamination was low it wouldn't require much of a brisk current of gas to remove any. But I suppose it is best to be safe than sorry and use Argon, then fractionate/distill the PCl3.

I like the sound of this method Sauron. You say you can get PBr3 but you also said it was too precious. Am I correct in assuming you can get hold of PBr3 unlike PCl3 but that PBr3 is exceedingly expensive? If so I suppose you don't want to risk losses in the protocol and using Argon would certainly reduce any potential losses.

Sauron - 18-2-2009 at 03:24

I have a liter of PBr3. I pay approx 2X the ex works price, which is shipping and import costs. I do want o have confidence in the method, and yes I will use Ar atmosphere to prevent atmospheric oxidation. Just opening a sealed bottle of PCl3 starts the process of oxidation, slowly at ambient. Bubbling dry air or O2 through PCl3 will convert it over time to POCl3 and if moist, H3PO4. Kind of expensive for H3PO4.

panziandi - 18-2-2009 at 05:08

I know that PCl3 oxidises to POCl3 but what about reaction with nitrogen? I keep my PCl3 is a full bottle, I originally had a litre and when I used half I moved it into a 500mL bottle to save the headspace since it's not a chemical I often use!

Sauron - 18-2-2009 at 06:56

I would be wary of distilling it or refluing it under anything but Ar.

At ambient, any reactions are probably too slow to matter.

S.C. Wack - 18-2-2009 at 19:56

Quote:
Originally posted by Sauron
I do not know where (or if) I can lay hands on Philosophical Magazine in syberspace.


Others can. I posted a direct link to the very article in question when I returned to the "Something Else to Do with Your Red P" thread 2 days ago. Here it is again for those not listening.
http://books.google.com/books?id=g08EAAAAYAAJ&pg=PA345

However, I
Quote:
Originally posted by Sauron
can go to hell and take google books along with you.


Since I already tried to help him view these pages and was inexplicably violently rebuffed, someone who desires to do so will have to convert this to a Sauron-approved format.

Sauron - 18-2-2009 at 20:27

Do you prefer a private apology or a public one? I will do either or both.

That link works. I can read the Gladstone paper from Phil.Mag.

However, I cannot save it, nor can I print it.

I downloaded Google Books Downloader and tried to install it, it crashed at once. Well, it is an alpha after all. That however does not get the job done.

The paper states that "chloride of mercury" (without specifying Hg(I) or Hg(II)) displaces Br from PBr3, and that similarly I2 is displaced from PI3 by either chlorine or bromine.

So far I have seen no mention of the use of the elemental halogens to effect this, although Mellor syayes it does claim so.

I do not know why the link you provided earlier failed, nor why the one not_important provided also failed. I can try getting to this in archive.org as I know how to d/l from there.

Anyway thank you for the assistance, I regret the earlier unpleasantries, I withdraw my remarks, and will endeavor to avoid any repetition.



[Edited on 19-2-2009 by Sauron]

not_important - 19-2-2009 at 00:49

Try this, a grab and slight cleanup of the text version displayed by Google Books. U2U me with questions on text and I'll try to fix them from the G.B. image version.

I'm happy because it confirms something I suspected

3 PBr5 + 5 PH3 = 8 P + 15 HBr

in two steps:

3 PBr5 + PH3 = 4 PBr3 + 3 HBr

PBr3 + PH3 = 2 P + 3 HBr

which gives a medium temperature route to elemental phosphorus from on of the commercially available phospides through reaction with halogen for PX3/PX5 and with aqueous acid to PH3 (yeah, toxic)

Attachment: On the Compounds of the Halogens with Phosphorus by Gladstone.txt (26kB)
This file has been downloaded 889 times

Sauron - 19-2-2009 at 02:35

Thanks but I already learned how to get the image files, by a roundabout method.

1. Go to the book you want

2, Now go to Documents and Settings/Administrator/Local Settings/Temporary Internet files and delete all
Now return to the google book and slowly page through it.
Then Refresh
Now back to the temp internet files folder and Refresh.

Save all the PNG files. Those are the page images.

This is not without ptoblems and a price.

The price is all temp settings are lost

That includes logins, such as email, this forum etc

The problems are that Acrobat Pro 8.1 barfs on about half the PNGs. When that happens, I use Photoshop to open the PNG and save as a PDF. Acrobat then recognizes it. I then renumber the pages and compile the pdf.

All right for a short article, a nightmare for a BOOK!

Goodle Book Downloader does not work.

Leech-something does not work.

Printing to PDF does not work.

So, I must still regard Google Books as being of questionable utility except when the files can also be found at archive.org from which they can be downloaded by the FTTP function.

But I do appreciate your efforts once again.

Finally, the scan quality is really rather poor so I doubt that OCR was of too much use.

Yes phosphine will take PBr3 down to P. Now calculate how much % wt P is of a Kg PBr3 - rather expensive. OK you can generate PH3 from phosphid but it is not without hazard,. Still, that is WP not RP.

The tidbit I found was that the mercury halide is (I) not (II). based on balanced equations in the text. Mercurous chloride. Mellow got this detail wrong, or at least was ambiguous about it.

The procedure is to distill the trihalide from the mercury salt. Thus, PBr3 + 3 HgCl -> PCl3 + 3 HgBr, Gladstone said nothing about Cl2 gas accomplishing this reaction, at least not in this paper.

[Edited on 19-2-2009 by Sauron]

Attachment: PhilMagGkadstone.pdf (998kB)
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PHILOU Zrealone - 19-2-2009 at 04:45

Hi Sauron,
Maybe the following procedure will work with less troubles:
1°)Fit the page in the Google Book link with the zoom tool to get the full page at screen.
2°)Alt-Ctrl-Print Screen
3°)In an open word document Ctrl V adjust the margins to minimal in a way to maximise image into the word document.
4°)Save with name x.doc
5°)Do a pdf of x.doc to make a x.pdf document.
6°)With the selection tool make a selection window into your x.pdf to fit the book page at best.
7°)In an open word document Ctrl V adjust the margins to minimal in a way to maximise image into the word document.
8°)Save with name final.doc
9°)Do the same procedure from 1°) to 6°) but for page 2
10°)Open final.doc go to the end of the page after the last image eventually set a page break ina way to be certain the next image goes to the next page then Ctrl V adjust the image in a way to maximise image into the word document.
11°)Save with name final.doc
12°)Repeat procedure from 9°) to 11°) for next pages.
13°)When the document is large enough and that you have all wished pages
Do a pdf of final.doc to make a final.pdf document.

In the word programma you can eventually make a landscape to put 2 images next to each other per page...making the final document look like the original book and maybe improving the scan quality by zooming a bit out.

Sauron - 19-2-2009 at 05:11

Won't that screen dump give me everything and not just the page window?

And at screen resolution?

Thanks for suggestion anyway.

not_important - 19-2-2009 at 05:56

In this case the OCRed version seemed quite good, I wonder if Google has enhanced it recently. The only serious problem was around numbers with decimals, 0:O, 1:l or I, and 5:S being the most common. That's what I corrected, the rest of the text save one equation looked good.

Your image capture looks to be Windows & IE specific. For Firefox the Web Developer plug-in will show all images, which in this case includes the current, previous, and next pages as PNG images. Save the images, giving them unique names, then page forward 3 pages to get the next triplet. I did that to start with, but the text view looked so good that I went that route.

Sauron - 19-2-2009 at 06:10

Yes it is IE specific. The webpage with instructions specifically mentioned it would not work for Firefox.I regard it as an emergncy expedient procedure only.

Now that it is clear that Gladstone was talking about mercury (I) chloride, calomel, and not the bichloride, the stoichiometry is shown to be

PBr3 + 3 HgCl -> PCl3 + 3 HgBr

Yeah I know HgCl is really Hg2Cl2 and likewise for the bromide, but equations with noninteger components make me uneasy.

Bottom like is MW PBr3 is 267, and that of Hg2Cl2 is 478. So it takes c.700 g Hg2Cl2 to change 1 mol PBr2 to PCl3. In that process, the phosphorus compound loses 132 g/mol while the Hg compound gains same.

We are left after distillation with 830 g Hg2Cl2 in the pot and 130 g PCl3 in the receiver.

The problem therefore is recovering the Hg2Cl2 as such because the bromide is no good to us.

It is insoluble in water, as it is non-ionic. I would like to find a direct transformation to Hg2Cl2 but I fear that it is more likely that it will have to be recovered as Hg metal, dissolved in cold dilute HNO3 then precipitated with NaCl.

Any shortcut to Hg2Cl2 from mercurous bromide?

[Edited on 20-2-2009 by Sauron]

Sauron - 19-2-2009 at 23:51

I spent last night and this morning trying the usual sources for information on Gg2Cl2 prep beyong what I have above.

Inorg,Syn, nothing
Brauer, nothing
Merck, no references
Ullmann, one reference but AFAIK inaccesible:

Pharm. Ztg. (1930) p 11

The 1911 Britannica is a bit more helpful. Solutions of stannous chloride will reduce Hg2Br2 to Hg2Cl2, and if in excess, to Hg metal. So I can recycle the Hg2Cl2, and when done preparing PCl3, recover the Hg metal.

I would still like to have a little more quantitative information, such as the best molar concentration of HNO3 for dissolving Hg ("cold dilute") being a little vague) the rest can be worked out via stoichiometry. The mercurous nitrate soln in dil HNO3 is used in situ to react with NaCl, the precipitate being very dense will settle fast, supernate decanted and the powder washed free of acid then dried with absolute ethanol to remove water, then vacuum dessicated. Then it is ready for PBr3,

not_important - 20-2-2009 at 01:28

Quote:
5. Mercurous Nitrate or Nitrate of Suboxide of Mercury,

Preparation.—1 part of pure nitric acid of 1.2 sp. gr. is poured on to 1 part of pure mercury in a porcelain dish, and the vessel allowed to remain for twenty-four hours in a cool place; the crystals which are formed are separated from the undissolved mercury and the mother liquor, and dissolved by grinding them up in a mortar with water which has been previously mixed with one-sixteenth part of nitric acid. The solution is filtered and kept in a bottle with some metallic mercury sufficient to cover the bottom of the vessel.

Tests.—With dilute hydrochloric acid, the solution of mercurous nitrate should give a copious white precipitate of mercurous chloride; sulphuretted hydrogen should produce no precipitate in the filtrate from this, or at most only a trifling black precipitate (sulphide of mercury).


Qualitative Chemical Analysis By C. Remigius Fresenius, Charles Edward Groves 1887

Queen Victoria is a friend of the chymist.

Sauron - 20-2-2009 at 02:20

Thanks. There is also a prep in "Synthetic Inorganic Chemistry" in the forum library, employing 25 g Hg and 20 ml 6 M HNO3, again a slight excess of acid. This is a 125 mmol scale.

So one would then add an equivalent of NaCl as a satd soln I suppose and Hg2Cl2 will drop out..

I have at least a Kg Hg on hand, this beats the hell out of paying Acros an absurd price for Hg2Cl2. They want $400 US/Kg, almost and by the time it gets here I will be paying $750 US.

Whew! glad to dodge that bullet.

Thanks once again!

By the way, folks, this procedure releases a lot of NOx, so trap it and scrub it or do it in the hood.

Here is the German version of Gladstone's article, this in J.prakt.Chem.

I will have to wade through this to see if Dr.G. said anything about Cl2 displacing Br on PBr3 as attributed by Mellor.



[Edited on 20-2-2009 by Sauron]

Attachment: JPraktChem,1850,49, pp40.pdf (562kB)
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Sauron - 20-2-2009 at 08:31

Gladstone does say that the relative affinity for P of the halogens is Cl>Br>I and yes he does specifically state that this exchange is accomplished by either the elemental halogen or, by the Hg(I) halide.

Thus, per Gladstone, PI3 is converted to PBr3 by Br2 or, by Hg2Br2. PBr3 is converted to PCl3 by Cl2 or Hg2Cl2. I2 has no such effect on either PCl3 nor PBr3 and neither does Hg2I2.

PI3 is too costly to be of use in this fashion of course.

The bone I have to pick with MEllor is that Gladstone was specifically talking about mercurous halides but Mellor cited Gladstone as saying this reaction is performed by mercuric halides. Gladstone did not claim this. We now have Gladstone in black and white in English and German and nowhere does he say mercuric chloride HgCl2, or bichloride of mercury, or corrosive sublimate. He gives the equation and it is for HgCl (corresponding to Hg2Cl2) and he names it as chloride of mercury not bichloride.

Now for all I know HgCl2 may work, but the point is that, that isn't what Gladstone wrote.

So it always pays to go to sources.

[Edited on 21-2-2009 by Sauron]

Attachment: Page 1033 from Mellor ACTOITC 8 N_P.pdf (112kB)
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Sauron - 20-2-2009 at 11:52

I just downloaded the classic 63 page Baudrimont paper from Ann.Chim.Phys. (1864) so frequently cited in Mellor Vol VIII, on the chlorides and bromides of phosphorus.

[Edited on 21-2-2009 by Sauron]

Attachment: Baudrimont.pdf (2.1MB)
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