Wetzelrad wrote: ↑Mon Jan 26, 2026 9:21 pm
I hope my post above adequately answers your chemistry arguments.
As to the timeline, we can establish it more definitively by using
this edition of the museum's
Varia magazine. Page 14 gives "autumn of 1942" as the estimated date that the bunker was built. Page 16 tells us that the damaged roof was not dismantled until 1947, which could mean the 1946 photo dates to as late as that. If we stretch, we could say this gap in time was at a minimum 3.25 years and at a maximum 5.33 years.
But the main problem with this timeline is that we don't know when the stains did form, only when they didn't. As of the 1946 photo, there is no sign that they have begun to form, not even faintly. The earliest images I can find of the stains come from tourist videos in the early 2000s. It's not known how many years or decades passed before the stains were created.
The platerers article you link appears to be AI. Not that I see any errors in it, but AI is making it increasingly difficult to find useful and reliable information by web search.
Yes, quite helpful as always Wetzelrad, thank you.
So from my current persepective, and as supported by not only Rudolf but Green also is that the situation is presented as a mechanism for a delayed PB formation is indeed possible at Majdanek, it simply depends on certain variables. Notably, one thing missing from the timeline is when the fumigations
began. Do we know if the fumigations began immediately after completion in late 1942, or perhaps delayed somewhat until 1943?
If not, then i'm happy to go with your timeline that fumigations began in late 1942.
With that then, the variables are 1) pH of the plaster, and 2) composition of the plaster. Re the plasterers link, yes fair enough, but i wanted to take the most mainstream, non-controversial everyman source I could find, just to demonstrate how commonly understood this concept is. So the recently plastered wall, late 1942, began with a pH in the range of 12-13.
We are indeed almost finished with TCOA, but not with Rudolf quite yet, because it's interesting to frame this mechanism in Rudolf's "Prussian Blue Formation in Five Steps", from 6.5.1 of TCOA. It is step 3, or step c as he denotes in the book that we are most interested in here.
This step as per TCOA is written as:
Complexing of trivalent iron (Fe3+) to the complex iron(III) cyanide (hexacyanoferrate(III)), that is, the displacement of oxygen and/or OH- ions in rust by cyanide ions
We can move now to the Rudolf / Green exchanges to see where it is stress-testesd and, funnily enough, this exact step is where they part ways - although not from a disagreement on the mechanism / process, but specifically on the presence / absence of the variables - which is also relevant for us in the Majdanek case!
In his article titled "
Some Considerations about the Gas Chambers of Auschwitz and Birkenau
Complexing of Fe3+ with 6 molecules CN- to [FeIII(CN)6]3-. This requires reactive iron
which is part of all mortars and concrete due to the sand and/or cement added, which
frequently has an iron oxide (i.e. rust) content of 1 to 4%.[18] The reactivity of iron
increases with decreasing pH-value. This means that at pH-values beyond 11 (to be found
in freshly mixed mortars and concrete) the complexing step is unlikely, because the iron
complexes are no longer stable.
From Green's reply, the article called "Chemistry is not the Science":
Step three. Without this step, Prussian blue will not form by Rudolf's mechanism. Alich et al.
[57] exposed Fe(III) to CN- and observed no Prussian blue formation within the timescale of the
experiment. This fact shows that step 3 is not a fast process by any means, and yet it is a
necessary step. Cyanide ions in the presence of Fe3 do not reduce the iron. Rather, the iron
must already be complexed to cyanide in the form of Fe(CN)63-.
Rudolf notes correctly that basic environments inhibit this process. An oversimplified way of
considering this reaction is the following reaction:
Fe(OH)3 + 6CN- <=> 3OH- + Fe(CN)63-
in which we have omitted the complexing of water molecules for simplicity. Lechatelier's well-
known principle predicts that a higher concentration of hydroxide ions (OH-) should drive this
reaction to the left. The basicity that Rudolf needs to have even a snowball's chance in hell of
producing Prussian blue by his proposed mechanism (under the conditions in the gas
chambers) inhibits the formation of a necessary precursor! Rudolf claims that the pH must
reach 11 to hinder the process, but offers no support for this assertion
So as we can see, Rudolf and Green essentially agree on the chemistry (as you would expect) but disagree on conditions and variables within the mortar. This obviously is in the context of Brirkenau so I won't address Green's argument here, but want to zone into the last sentence, as this is what applies to Majdanek. "Offers no support for this assertion" is ludicrous from Green, as i've demonstrated above, very high alkalinity of fresh mortar / plaster (12-13) is commonly understood, even from mainstream sources.
From his postscript:
Rudolf makes a minor point. Rudolf's claim that a measurement of the pH many years later may
not be indicative of the pH at the time is valid. Unfortunately we cannot go back in time and
measure the pH. Notwithstanding that fact, our conclusions about Prussian blue formation
simply do not hinge on the pH. Rudolf has argued for a high pH because it makes the possibility
of reduction more likely. On the other hand a high pH makes the formation of a necessary
precursor to Prussian blue less likely. In the end, even granting Rudolf his high pH, our
conclusions are valid, and we point this fact out in the article.
To which Rudolf then rebuts in "Dr Green's Evasions":
I strongly recommend that Green finally consults some literature on building materials -- as I did
in preparation of my report -- so he can find out for himself that my claims about considerably
higher and longer lasting pH values in cement mortars as compared to lime mortars are true.
There is no need to "go back in time". Just stop ignoring the facts, my quoted literature, and
start going to a library! Also, it might well be that his argument does not hinge on the pH value,
but that is only because his argument is flawed, as the pH value strongly influences the
equilibrium concentration of cyanide ions in aqueous solutions (see my subchapter "pH Value,"
and especially Graph 5). I therefore have to repeat that Green keeps ignoring the most
important facts. As a matter of fact: lime plaster older than several weeks (pH of ca. 6.5-7,
delousing chambers) accumulates a concentration of cyanide 10,000 to 100,000 times lower
than of a cement plaster of several weeks (pH 11-12, all in equilibrium and at the same
temperature). How can anybody claim that this issue does not hinge on the pH value?
As per the 2nd variable, composition as I called it above - I'm almost certain we don't know if the plaster of this wall in Majdanek is lime plaster or cement plaster. Cement plaster obvious is more favourable for "delayed" reaction, and lime for "quick" reaction.
