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Making silver cyanide from silver nitrate

Q. I want to make silver potassium cyanide.
Please explain whole process.

Manoj Shahane
Employee - India
January 21, 2024

A. Hi Manoj. If you find Chris & Richard's answers below inadequate, please see
Luck & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha - Pine Beach, New Jersey

⇩ Related postings, oldest first ⇩

Q. Hi,

Has anyone tried to obtain silver cyanide from silver nitrate? What is the exact amount of potassium cyanide needed to form the silver cyanide, apart from the observed case where the cyanide is poured into the silver nitrate solution until no more whitening occurs. Any help will be appreciated deeply.

Best Regards,

Gazi Erhan Erel
electroplater - Istanbul, Turkey

Hydrogen Cyanide Detector

on eBay or


(affil links)

!! Hi, Gazi. Silver potassium cyanide is readily available from plating suppliers (you may already know that, but I post it because so many readers assume that they must make up plating solutions from raw chemicals, not realizing that there is a whole robust industry of suppliers offering complete proven silver electroplating processes complete with instruction and technical service.

(Readers: experimenting with silver chemistry and/or cyanide is only for trained and experienced chemists.)

Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

Q. Thanks for the advice, but I am already experienced in making silver cyanide, and am aware of the hazards -- I was only asking an analytic question.

Gazi Erhan Erel [returning]
electroplater - Istanbul, Turkey

"Antidotes for Poisoning by Cyanide"

on AbeBooks

or eBay or


(affil links)

thumbs up sign Thanks for letting us know, Gazi, and good luck! Beyond mentioning the obvious KAg(CN)2 stoichiometric relationship, I can't offer the analytic answer you seek, but hopefully an experienced reader will.

(Readers: please remember that the internet is a gigantic one-room schoolhouse, and it is reckless for inexperienced people to proceed based on answers that are intended for trained & experienced chemists like Gazi.)

Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

A. It's a one to one relationship between the atomic weights of the various components.

For 107.868 grams of silver (169.87 grams of silver nitrate), it will require 65.12 grams of potassium cyanide. This will produce 133.84 grams of silver cyanide. This is assuming pure, dry chemicals and the total absence of nitric acid.

Any excess of potassium cyanide will dissolve some of the silver cyanide already formed. An excess of 65.12 grams of potassium cyanide will dissolve all of the silver cyanide.

Chris Owen
- Houston, Texas

A. I made silver cyanide for eleven years. We made it with a one pound per gallon solution of sodium cyanide (more economical) and an eighty to eight-five troy oz/gallon solution of acidic silver nitrate. The silver nitrate had to have a pH of no more than one. This manufacturing process is done with a great deal of ventilation! Slowly pump the NaCN solution into the agitating AgNO3 solution (it will get hot) The 'general' ratio used was 33 lbs of sodium cyanide to 1000 tr oz Ag. (adjustments are necessary to finish reaction). The low pH on the AgNO3 solution was to prevent Ag2O from forming and creating a grey/brown AgCN precipitant. Test supernatant with HCl; if no turbidity occurs the reaction is complete. Load slurry into fine mesh centrifuge, rinse with DI water until pH is neutral, spin, scrape, dry, grind, package, ship, go home and have a beer.

Richard Eldred
Electrochemical Manufacture - Apopka, Florida, USA

Q. Thanks for the interesting article re. making silver cyanide using silver nitrate and sodium cyanide.

Is there any danger of releasing hydrocyanic acid gas when making silver cyanide by this method?


Mike Van Moppes
St. Leonards, Sussex, England

A. Hi Mike. Yes. of course! Mixing cyanide with acid (hydrogen ions) is how you make hydrocyanic acid gas (hydrogen cyanide). This procedure is for experienced chemists who know cyanide inside out, and as Richard noted: "The silver nitrate had to have a pH of no more than one. This manufacturing process is done with a great deal of ventilation!"


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

Q. I am interested in manufacturing this product for electroplating industry. I need some help in order to make up this salt. Any procedure, equipment. Thanks in advance for your support
Kind Regards,

Victor Meneses
supplier - Lima, Peru
September 1, 2011

Q. I want to know how to produce silver potassium cyanide.

Krunal Rana
- Surat Gujarat India
May 14, 2013

Hi cousins. Chris and Richard already answered those questions in substantial detail. Please try your best to frame continuing questions in terms of the highly informative answers already provided -- simply starting a thread over usually only kills it off :-(

Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

Q. Hi everyone, it's nice to know that there are some people with a long experience in plating stuff. I'm 15 years in the market as a supplier, but now I'm interested in the best way to dry the silver cyanide, I have made it for over 10 years but it's too hard to dry on a hot plate; it's too long time and boring, but I do not want to risk burning it.

Kind regards... thanks

Fabio Bell
- Mex. City, Mexico
May 29, 2013

Q. Hi,
I've a company and we're starting production of silver cyanide, but I would also like to learn more about the drying process, and what is the ideal temperature to do it.
It would be perfect to me, if you all experts, could give me your email or contact me by e-mail.
Thank you all,


Omar Carreón
- Chihuahua, Chihuahua, México
June 7, 2013

Hi Omar. Hopefully you'll get the answers you seek by publicly engaging in the dialog with Fabio and others here. There are an average of a thousand readers for each poster, so one of the reasons we don't help put people into private contact is that it disenfranchises the 999 other readers who were following the discussion ... just when the time they spent tracking down the right conversation is about to be rewarded, the conversation is hijacked and taken private, cutting them adrift :-)

Please keep it all public!
Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

"The Cyanide Industry"
(reprint of very old book) AbeBooks

or Amazon

(affil links)

Q. I have recently stumbled upon an interesting method of making silver and copper cyanide from potassium ferrocyanide. According to "The Cyanide Industry: Theoretically and Practically Considered" .
p 94 (available for free on google books)

6N03Ag + FeCy6K4 => 6CyAg + 4N03K + (N03)2Fe, and

6S04Cu + FeCy6K4 + 3S02 + 6H2O => 3CuCy2 + 2S04K2 + S04Fe + 6S04H2.

It is called the Bergmann Process. Now this is an old method from an old book. I haven't attempted it or found corroboration anywhere but I was thinking it might be worth a try. What do you all think? Is it true?

Mike Keller
- Denver, Colorado, USA
June 23, 2013

thumbs up signThanks Mike. There is no "Cy" in the periodic table, so let's not confuse the school kids who frequent this site :-)

The book you referenced says that the reaction is "of little practical value" -- but I'm not sure why ... maybe it's hard to make practical use of silver cyanide which is so heavily contaminated with nitrates & iron that electroplating from such a solution isn't workable? Good luck.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
June 24, 2013

Q. Hi,
I made silver cyanide from pure silver. First I dissolved the silver in nitric acid and then added KCN. please answer me:

1- how do I eliminate N2O gas?
2- before adding KCN, what kind of base solution do I have to use for inhibiting the production of HCN?

ali kabar
- Tehran,Iran
August 4, 2014

A. I would go about this a little differently.

Make the silver the anode in a divided electrolytic cell, with KCN solution as the anolyte, and KOH the catholyte. This will yield relatively pure AgCN solution.

Or, one could precipitate the Ag from the nitrate solution with sodium carbonate, dissolve in NaCN solution, and "freeze out" the excess carbonate. This will give you NaCN, not KCN, but perhaps you could make that do.

dave wichern
Dave Wichern
Consultant - The Bronx, New York
September 3, 2014

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