Talk:Novichok

Novichok
Mirzayanov book also has molecule drawings of
 * A-230 Substance 84 the first one synthesized in 1981 by Petr Kirpichev, formula molecule drawing in Mirzayanov's book (2009)
 * A-232 (Novichok -5), synthesized in 1987, molecule drawing in Mirzayanov's book, said to accidentally poison scientist Zhelezhnyakov, said to be binary, and the only binary agent developed in the USSR
 * A-208 (substance 33), VR gas, Russian version of VX;
 * A-234 Chemspider; info about NIST98 (this is presently not on NIST webbok
 * A-242
 * A-262
 * Also, he gives Russian code names of Sarin (A-235); Soman (A-255) (no drawings for those).

Mirzayanov  arrest date, 22 October, 1992.

Early 1990's developments are said to be
 * Novichok 7, 'based on A-230 but 10 times more toxic';
 * Novichok -8, Novichok-9 synthesized in 1990's, tested at the testing grounds in Shihan, not far from Saratov, and in Nukus in Uzbekistan.

Sources for Novichok 7,8,9:
 * Нервно-паралитическое вещество под кодовым названием "Новичок"-RIA, March 13, 2018
 * Жертвы "Новичка". История яда, фигурирующего в деле об отравлении в Солсбери -Svoboda.org, March 13, 2018

Original sources for Novichok 7,8,9 claims are unclear, molecular formulas or drawings not known to us. --Resup (talk) 18:25, 13 March 2018 (UTC)

Some useful information on Reddit. -- Petri Krohn (talk) 11:34, 18 March 2018 (UTC)

First murder using Foliant (Novichok) agents - in 1995

Russian FM press briefing, MOD representative (Gen. Kirillov--chemical control--  presentation): in Mirzayanov book, not only formulas (correct) but also synthesis procedures (have not seen the latter myself) Live stream, Russia 24 --Resup (talk) 12:55, 21 March 2018 (UTC)


 * The synthesis procedures are given in great detail in the 2016 Iranian paper referenced elsewhere in this page --Charles Wood (talk) 13:16, 21 March 2018 (UTC)
 * Yes, that's for sure, but according to presentation, (some) synthesis details were already in Mirzayanov book of 2008--Resup (talk)


 * Russian Ministry of Defense: 'the formula of the substance used in Salisbury published in the US back in 1998' -RT, March 25, 2018
 * Rybalchenko, the chief of analytical chemistry laboratory, RU MoD, says that they got interested in the spectral data of an organophosphate compound published by the National Bureau of Standards,  USA in 1998, believing it must be very poisonous; and now based on the chemical name (presumably the long standardized chemical name) of this compound they believe it is Novichok A 234. (No further details, really; somebody who can correctly name A 234 may be able to check the assertion; it may be online, but perhaps not everything they publish is online) --Resup (talk) 19:42, 25 March 2018 (UTC)

Other investigators
Several names of scientists (or whistle-blowers) have been mentioned on our pages already, scattered somewhere. More names:
 * RIA Novosti interview with Professor Leonid Rink, March (21?), 2018
 * Did you have anything to do with creating what the British authorities call the "Novichok"?
 * Yes. This was the basis of my doctoral dissertation. At that time I worked in Shikhany, in the branch of GosNIIOKhT (State Research Institute of Organic Chemistry and Technology, during Soviet times was engaged in the development of chemical weapons), was a leading researcher and a head of the laboratory. Mirzayanov was simply a chromatographer (a chemist who deals with the separation and analysis of various mixtures of substances.) - Ed.). Analytic tasks in this field were not even connected with him. But he headed the department of countering foreign technical intelligence, defended our developments, so he had all the permissions. He did not take part in discussing the systems that were being created, he had no relation to the development of the system. Nevertheless, since among themselves the scientists are discussing everything, he was aware.
 * Kivelidi murder; Chechens. It was Rink who sold the ampoule with the poisonous substance to the mediator who gave it to the murderer. The poison was applied to the telephone in the office of Kivelidi, and his secretary also died. Igor Rink was given a conditional year (he also sold the substance to certain Chechens).1,2.
 * The mystery of the Rinks -Echo Moskvy, March 21, 2018
 * Leonid Rink, doctor of chemical sciences said to be one of the developers, confirmed that Nikolai Rink (who was accused of smuggling poisonous substance from the lab and a role in Kiveldi murder) is his father.
 * Vladimir Uglev (The Bell Eng., Rus., March 20, 2018), see also this section

Военные мафии Кремля (Military Mafias of Kremlin, Georgy Vachnadze, pp 119-120, Moscow 'Mir' and Marburg Blau Herner (1994)

Kuntsevich was accused of a deliberate lie by one of the real, but robbed by the rogue authorities  authors of this binary chemical weapons, Vladimir Uglev. The widely publicized "Mirzayanov's case" was a continuation of the "Interview with a Loop on the Neck" story in the weekly Novoye Vremya (No. 6, 1993; we referenced below a translation, pp. 18-19). According to Uglev, Lenin's award to A. Kuntsevich, V. Petrunin (director of the head military chemical research center of the State Research Institute of Organic Chemistry and Technology) and S. Golubkov (first deputy minister of the chemical industry of the USSR) could be issued only after the production of a pilot binary industrial batch weapons, "components of which are now stored on a secret base in the Bryansk region."

Uglev has the dubious honor of authorship of three out of five "combat options" of binary weapons, code-named "Novichok". Nothing of the kind has ever been done in the world after the most powerful poisonous gas, synthesized by the Swedish scientist in 1956(inaccurate attribution?), the VX gas. The discovery of Uglev and his colleagues is 5 to 8 times more deadly than VX, not to mention other phosphoric gases - Sarin and Soman.

"The substance synthesized by me," says Uglev, "can be relatively easily" disguised "as a product of peaceful chemistry in the event of an international inspection. Uglev confirmed Mirzayanov's statement in the press that in the list of chemicals and dual-use technologies published in September 1992, under Yeltsin's signature, almost all components of both the new binary and the former VX gas are missing, ...

Federation of American scientists publication, Ch.2, Russia, p.133, date not supplied

But in the fall of 1992, the MBR detained Vil Mirzayanov on the charge of disclosing state secrets. Mirzayanov had publicly written that Russia was working on a nerve gas weapon, which questioned Yeltsin’s statement in January 1992 that Russia would comply with the US-Soviet agreement on nonproliferation of chemical weapons. Vladimir Uglev, who was one of the chief chemical weapons designers, corroborated Mirzayanov’s allegations though no charges were filed against Uglev for revealing state secrets because he had deputy’s immunity as an elected official.


 * --Resup (talk) 16:29, 21 March 2018 (UTC)

Kholstov
Victor Kholstov, chemical defense chief, talking after a question of lower-level UK representative woman (Ambassador not attending):

No formulas in Mirzayanov claims in 1990's, or in his book first published in Russian in early 2000. However, Czech(oslovakia) professor Matoushek (Jiri Matoushek from Brno, Czech republic?) around 1994 published (toxicology) details of several chemicals (for the purpose of defense against those). Another professor from Czech(oslovakia) whose name is Ivan Masek (this?) published toxicology and spectroscopy data in 1994 of 'several dozen' chemicals (also for defense purposed). Kholstov flashed several pages presumably with formulas and related information.

Studies, according to Kholostov, were conducted by Edgewood Arsenal (USA).

Information on new substances was received at OPCW; however chemical convention was already signed, in the processs of implementation, and amending documents will slow this down.

Presenters earlier stated that in 1996/1997 Russia destroyed its chemical weapons under international control

When Mirzayanov book (the US one, on Amazon) appeared and was about to appear, it was sent to OPCW, and OPCW technical council/secretariat/commission seriously studies it. Their conclusion is that (it may need further study in case of concern but there is no definite data confirming its properties at this stage).

Kholstov alleges that publication of Mirzayanov was (1) for financial reasons (2) possibly coordinated with Edgewood Arsenal.

(PS. Quoted as briefly scribbled/remembered from live stream; for exact phrasing see transcript, hope they will issue one, or video at least)--Resup (talk) 13:44, 21 March 2018 (UTC)


 * Transcript: Briefing by Director of the Foreign Ministry Department for Non-Proliferation and Arms Control Vladimir Yermakov, Moscow, March 21, 2018, Eng.,Rus.

Making Novichok
Novichok/derivatives synthesised at laboratory scale by CW researchers in 2016. Samples used to calibrate Mass Spectrometer equipment for later detection of field use of the agents.

Fragmentation pathways and structural characterization of organophosphorus compounds related to the Chemical Weapons Convention by electron ionization and electrospray ionization tandem mass spectrometry

The paper includes precise synthesis instructions including where to source the raw materials (Sigma Aldrich)

Citation:


 * Hosseini, S. E., Saeidian, H., Amozadeh, A., Naseri, M. T., and Babri, M. (2016) Fragmentation pathways and structural characterization of organophosphorus compounds related to the Chemical Weapons Convention by electron ionization and electrospray ionization tandem mass spectrometry. Rapid Commun. Mass Spectrom., 30: 2585–2593. doi: 10.1002/rcm.7757.

(Someone with more skills than me may care to make it a proper citation entry) --Charles Wood (talk) 18:13, 16 March 2018 (UTC)
 * Resembles A-230, A-242 from the book but different chain following N of P-N  (unclear how derivative is the derivative...). Noted, Methylphosphonyl difluoride (cpd 1 in the article) is not from the shop and is a CW precursor  --Resup (talk) 20:14, 16 March 2018 (UTC)


 * As resup notes. it is not entirely clear if they are making actual Novichok compounds or compounds with the same building blocks. We need a chem expert to comment. Irrespective, the syntheisis seems straightforward so making actual Novichok compounds should be equally as easy --Charles Wood (talk) 20:10, 16 March 2018 (UTC)

A summary of the state of affairs
 * Ryan De Vooght-Johnson, Iranian chemists identify Russian chemical warfare agents, Spectroscopy now, Jan. 1, 2017
 * ''The Iranian researchers synthesised five ‘Novichok’ agents, along with four deuterated analogues. They were all O-alkyl N-[bis(dimethylamino)methylidene]-P-methylphosphonamidate compounds (i.e. molecules with the typical nerve agent phosphorus group coupled to N,N,N’N’-tetramethylguanidine). The O-alkyl group was varied, with the methoxy, ethoxy, isopropoxy, phenoxy, and 2,6-dimethylphenoxy derivatives being prepared. The syntheses were carried out on a micro-scale in order to minimize exposure.
 * ''The data have been added to the Organisation for the Prohibition of Chemical Weapons’ Central Analytical Database (OCAD).
 * --Resup (talk) 20:39, 16 March 2018 (UTC)

Craig Murray has taken note of the Iranian research. The year is wrong. The original paper appeared in 2016, the summary in Spectroscopy now is dated January 1, 2017. -- Petri Krohn (talk) 21:28, 17 March 2018 (UTC)
 * First Recorded Successful Novichok Synthesis was in 2017 – By Iran, in Cooperation with the OPCW -
 * ''I have now been sent the vital information that in 2017, Iranian scientists set out to study whether novichoks really could be produced from commercially available ingredients. Iran succeeded in synthesising a number of novichoks. Iran did this in full cooperation with the OPCW and immediately reported the results to the OPCW so they could be added to the chemical weapons database.

Did the Novichok program exist?
A comment by yoffa on Moon of Alabama:


 * ''I think the underlying assumption of your post - that a Novichok programme existed - is open to serious doubt.


 * ''The only source for the story of a Soviet/Russian programme to develop a new class of military nerve agents codenamed Novichoks is a defector in the 1990s named Vil Mirzayanov. He claimed that one of these compounds was 5 to 8 times more toxic than VX and that production of these compounds had continued after the Chemical Weapons Convention came into effect. He explained the many publications in the open literature by Soviet chemists on compounds with similar structures as a deception to provide cover for secret research on other more toxic compounds, and gave structures for these compounds.


 * ''A review of chemical warfare agents in 2016 (http://pubs.rsc.org/en/content/chapter/bk9781849739696-00001/978-1-84973-969-6) by Robin Black, who had just retired as head of the detection lab at Porton Down, states that there is no independent confirmation of Mirzayanov's claims about the chemical properties of Novichok compounds.


 * ''The report of the OPCW's Scientific Advisory Board's meeting in April 2013 made a similar statement, and did not recommend adding these compounds or their precursors to the list of scheduled chemicals banned or restricted under the CWC. The members of the scientific advisory board included people who, like Black, were heads of western chemical defence labs. These labs would almost surely have undertaken experimental tests of Mirzayanov's claims about the toxicity of these compounds. So if members of the scientific advisory board who were in a position to know the results of these experiments did not recommend adding these compounds to the list of scheduled chemicals, we can reasonably infer that they were not found to be military grade nerve agents.


 * ''The British government is now demanding that Russia make a full disclosure of its Novichok programme by Tuesday evening. A Russian denial that such a programme existed will be taken as proof of guilt.

-- Petri Krohn (talk) 03:05, 13 March 2018 (UTC)

'Novichok' is a word, not a weapon. Anything not seen before out of a broad class of chemicals, pesticide or nerve agent, may be called 'Novichok' and used for propaganda. It needs to be (1) specific chemical (2) detailed signature of the recovered sample. There could be a program called 'Novichok' back from Soviet days, or maybe there was no such thing, in any case this is classified. They are not going to declassify it on the basis of a magic word pronounced, this is not serious. Give them sample details, and not through May-media. Otherwise this is is really justification for whatever measures they have already prepared. --Resup (talk) 09:20, 13 March 2018 (UTC)
 * Lavrov: Russia did not receive a request by the official channels (2) Russia 'immediately' (сразу же) officially requested access to the chemical [sample], and to all facts concerning the investigation, since Yulia Skripal is a Russian citizen. We have received 'an inarticulate answer' (невнятный ответ), and the request was 'denied' (отказано) --Resup(talk) 12:37, 13 March 2018 (UTC)
 * An amendment: it is said (see below) that 'Novichok' has over a 100 variants, with chemicals composing a few of them published by Mirzayanov (who was out of the program in the 1990's and since emigrated and works in academia in USA). Thus, a few (alleged) compounds are known, but with details openly published by 2009, others can figure out how to synthesize those; also with the development being Soviet, not Russian, other former USSR republics may have it too. For the unpublished versions of Novichok, the above comment applies, one can say that anything not seen or rare, of a broad class, is Novichok, in one of those many unpublished versions. And no leaks on Russian (i.e developed after 1991), not Soviet compounds. Compare with Theresa May statement, 'military-grade nerve agent of a type developed by Russia', etc. Peter Wilson later statement uses same language. --Resup (talk) 05:33, 14 March 2018 (UTC)

There is a good description of the alleged chemical weapons program in this document on pages 18-20. The Interview with Vladimir Uglav originally appeared in Novoye Vremya in February 1993 and was translated into English be the U.S. Department of Commerce. -- Petri Krohn (talk) 13:11, 13 March 2018 (UTC)


 * Uglev, p.18: During the entire 15 years of my work in the laboratory, more than a hundred substances of this class were synthesized. Only five of them representing a significant "war interest" went through the full investigation. The dubious honor of discovering three of them  belongs to me.


 * Also: according to the Russian Wikipedia it is a family which consists of more than a hundred similar compounds, not one thing. --Resup (talk) 13:36, 13 March 2018 (UTC)

Sakahrov center: Mirzayanov was charged for treason in Russia, but then released and the criminal case dropped. He then emigrated to USA, where he works at university as has his chemical lab there. He posted some twits on Syrian chemical weapons (opposing Syrian and Russian governments), reproduced on Cassad. Supports British version on Skripal --Resup (talk) 17:34, 13 March 2018 (UTC)

Moon of Alabama brings closure to this issue: -- Petri Krohn (talk) 19:45, 31 March 2018 (UTC)
 * Hillary Clinton Ordered Diplomats To Suppress 'Novichok' Discussions - Moon of Alabama, March 31, 2018
 * ''Until 2016 the OPCW's Scientific Advisory Board (SAB) as well as scientists at the UK weapon laboratory in Porton Down sowed doubts about the very existence of 'Novichoks'. We fell for this when we asked if 'Novichocks' exist at all. Until late 2016 the OPCW did not list the substances and their precursors. This was no oversight but intent. Active U.S. suppression efforts against any mentioning of 'Novichoks' in the OPCW already occurred in 2006.

Soviets made GV not Novichoks
Update to briefing note ‘Doubts about Novichoks’
 * Other than Mirzayanov’s story, there is no evidence that these compounds were ever synthesized in either the Soviet Union or Russia, or that the “Novichok” programme ever existed. The use of the term “Novichoks” to describe this A-230 series of compounds, which are real chemical structures, is therefore tendentious. An account by another Russian chemist Vladimir Uglev, often cited as corroboration of Mirzayanov’s story, appears on close examination to be about the development of a class of nerve agents denoted GV and which has been studied in several countries including Czechoslovakia and the US. --Charles Wood (talk) 18:35, 1 April 2018 (UTC)

I think this matter is unsettled. Uglev never gave specifics on chemistry (according to his statement, somewhere among our links). While Novya Gazeta report is a tricky one. Above the photo with the formula, it is stated that 3 organizations were asked to provide expert opinion, MOI forensic lab, ecology and evolution institute of the Russian Acad. Sci., and the GOSNIIOHT. The first two agreed on their conclusion (which I understand is shown on the photo of the molecule structure), while GOSNIIOHT 'added that is also contains Fluorine'. It it is unclear from the article whether GOSNIOHT submitted a separate detailed opinion and whether it is part of the court papers (which are secret). My feeling is that Novaya Gazeta could be  allowed to publish part of the secret material which was the least secret (or most inaccurate); that could also happen at the level of the court papers. (Court papers were secret while the case was considered in court, and I have no information they were ever declassified). Novaya Gazeta apparently published details of the opinion of the first two expert bodies but not the GOSNIIOHT to avoid being in trouble with the secrecy laws (or provided with a partial information only to begin with). Then they showed something to Mirzoyanov (possibly a fuller account of the court papers, or their own spin of those; we do not have such details) to have Mirzoyanov 'on board' saying that in his opinion, the substance in the case of Kivelidi poisoning belongs to the group of 'Novichok'(s) . Novaya Gazeta is pro-Western but also after sensations (as those sells), so they published all that hodge-podge  of things, adding mostly to confusion, not to understanding.

But in any case, even if Mirzoyanov is correct in his claims, that information was known for a long time, and Russia does not have exclusive knowledge even if it has such knowledge at all. So whether or not Novichoks were outside GV, it matters for weapons control but not for the issue of who is to blame for the Skripals poisoning. Russia never was forthcoming about its classified research and is not forthcoming about it here, but this should not be confused with the Skripals blame --Resup (talk) 21:14, 1 April 2018 (UTC)

Disinformation operation?
Andrey Lazarchuk writes on Facebook and also reposted here: -- Petri Krohn (talk) 02:23, 18 March 2018 (UTC)
 * Хвост вильнул собакой: оригинальная версия «дела Скрипаля» (Tail wagging the dog: the original version of the "Skripal case") - Andrey Lazarchuk, News Front, March 17, 2018
 * ''Brief Summary: "Novicock" is not the name of the CW, but the cipher of the KGB operation to detect the channel of information leaks, as well as the supply of disinformation

I have seen this, but my impression is that this is essentially denial PR. Several people came forward, Mirzayanov not the only one; one scientist, Zheleznyakov, received accidental poisoning (and said to support those coming forward), two more people said to die after unauthorized use. Most of it is coming from Mirzayanov, but I do not have an impression that he is intentionally lying. Disinfo campaign, a possibility in principle, but with the development running for many years with many people involved, colleagues, students, etc not likely. The attitude at the time of his publications was that CW program is going to be abandoned and convention implemented (thus Merzayanov was released and allowed to leave to the West); and KGB was in weak position overall, seen as repressive. So over-the top major disinfo effort, with massive staging, is not very likely, and if it was felt that CW are to be abandoned, -not very meaningful. -Resup (talk) 03:38, 18 March 2018 (UTC)

I also found this interesting:
 * The curious case of the Salisbury poisonings - natsouth, March 17 2018
 * ''Maybe there is a possible connection between the development of Novichok as part of a Soviet CW programme, codenamed 'Foliant' and an long-defunct US FBI counter-intelligence project, codenamed “Operation Shocker”. This was a long-running US operation aimed at wasting Soviet resources & money in trying to develop a new super nerve gas the US believed unweaponizable, known as GJ, deemed to be an hopeless unachievable programme. The aim of the US operation was to misinform the Soviets about the US CW and BW programmes, through a fake 'defector'.

Wikipedia has an article on "Operation Shocker", but no one has linked it to novichoks.

Disinformation both ways? Or maybe the information was all real, and the story about the disinformation operation was invented after the real information had been leaked. -- Petri Krohn (talk) 14:33, 21 March 2018 (UTC)

Detection?
Novichok 5, and likely 7,8,9 are binaries, presumably mixed on the spot from precursors. Detecting presence of the agent as such should be doable (GC; MS; spectroscopy, Raman spectroscopy, NMR), and there may be tests developed to do it quickly, but detailed signature pointing to the origin (purity, impurities, by-products, etc) is difficult as it is mixed locally and detailed composition depend on the local mix. So they need to find a way to do it despite those local mix variations (and essentially detailing precursors, not the mix), and it is not clear whether they are capable of doing it reliably (and quickly enough). Also, this needs to be done on real samples taken from victims or the scene and so containing lots of contaminants not just the agent (unless they found true source of poisoning, unclear they did). --Resup (talk) 20:37, 15 March 2018 (UTC)

The convention says: synthesis of Schedule 1 chemicals for research, medical or pharmaceutical purposes, but not for protective purposes, may be carried out at laboratories in aggregate quantities of less than 100g per facility. But 100g should be enough for what happened, and those 100g may be produced afresh, not taken from a big batch of CW in industrial quantities. In that case, no signature, or it is at least very difficult, or impossible if there are no further clues to help. --Resup (talk) 18:26, 17 March 2018 (UTC)

What is "weapons grade?"
The key factor in a weapons grade nerve agent is persistence, it does not evaporate - or as Vladimir Uglev describes them here, the chemical agents in the novichok series are "extremely tenacious." If the poison was a novichok or "weapons grade", then there should be residue where it was applied. How come the investigators have not found the spot of contamination? -- Petri Krohn (talk) 16:41, 21 March 2018 (UTC)

If it evaporates slowly, its concentration in the air is low, so it has to be effective at low concentration (and pure, as part of this). They also talk about cumulative effect with low exposure over long periods (so healing is slow/none). (But also, weapons grade may be not really defined, its whatever fits requirements set by the 'customer', and also not a DIY version of something better) --Resup (talk) 17:07, 21 March 2018 (UTC)

The key factors of weapons grade agents are that there must be a repeatable manufacturing process, a safe way of storing the chemicals with a militarily useful storage period, minimal risk to operators before deployment, a reliable means of delivery, and then depending on application either a long or short duration of activity after deployment. Nice to haves would be effective prophylactics and/or antidotes. Also, the agent should ideally create mass panic in victims or potential victims so as to multiply the casualties - psychological as well as physical. --Charles Wood (talk) 00:59, 22 March 2018 (UTC)

I guess this issue originates with Theresa May claim, It is now clear that Mr Skripal and his daughter were poisoned with a military-grade nerve agent of a type developed by Russia. But Russia destroyed its military-grade CW under OPCW control, around 1996. Claims of scientist were, if accurate at all, about development of CW, not mass production; they at most point at some other people having to do with mass production. But that mass production, even if it happened, was abandoned and destroyed. So Russia does not have weapon-grade nerve agents; as for small quantities, many countries could do it; but saying a small quantity is military-grade is meaningless --Resup (talk) 04:01, 22 March 2018 (UTC)

What is "Novichok class or closely related agent?"
What breakdown products would the scientists be testing for in blood samples to find a "Novichok class nerve agent or closely related agent?"

When sarin degrades to IMPA is retains its skeletal molecular structure with the fluoride (F) atom exchanged for a -OH group. Would novichok agents have similar fluoride-less analogs? -- Petri Krohn (talk) 06:38, 24 March 2018 (UTC)

Iranian paper discusses pathways of their compounds. Their cp4 has O=P-OH (they say OR), and that P also links CH3 and -N-....So I guess you need to knock off -N-... and replace by the -O-<C*H* that you show. Is it going to occur naturally in vivo, do not know, do not know chemistry well (but does not seem to be hugely impossible, no alchemistry required, just chemistry). I do not remember all Mirzayanov's straight away but I recall those with 0=P-O (P also links two other things, often F, and some CH's or N's). So I guess it's a similar answer, can be made to happen but unclear to me whether naturally happens. Maybe there are chemist reading this who can answer, I am not.--Resup (talk) 14:34, 24 March 2018 (UTC)

Paul McKeigue & al confirm what I was suggesting above:
 * ''This is similar to the form of words that OPCW has used to report positive blood tests for sarin exposure: “sarin, or a sarin-like substance”. This wording is used because blood tests for nerve agent detect only what is left of the molecule after it has bound to the receptor. The “leaving group” (the rest of the molecule) cannot be identified. For sarin (and presumably for A-234) the leaving group is a fluorine atom, and for VX the leaving group is a thiol.

-- Petri Krohn (talk) 21:10, 1 April 2018 (UTC)