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Author: Subject: Mercuric oxide from mercuric sulfate

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[*] posted on 7-6-2022 at 09:34
Mercuric oxide from mercuric sulfate

Hello everyone this is my first post on sciencemadness and I decided to open a new topic on the issue of converting mercury(II) sulfate to mercury(II) oxide as easily as possible. Some of you might already know me from youtube but I got access to this SM account today.

Here´s the procedure:

-mercury(II) sulfate (1mol; 296,65g) or another mercury salt
-sodium hydroxide (2mol; 80g) 90g were used
-distilled water (~800ml)

Step 1:
296,65g of mercury(II) sulfate were added to a 2L beaker alongside a stir fish. 400ml of distilled water were added. In a different beaker 90g of sodium hydroxide were dissolved in 400ml of distilled water. The sodium hydroxide solution was slowly added to the mercury(II) sulfate suspension in water under strong stirring. The beaker was covered and the water was held at 85°C for about an hour while stirring.
Step 2:
The beaker was allowed to cool back down to room temperature. A gravity filtration was performed and the mercury(II) oxide was rinsed with a lot of distilled water.
Step 3:
The product was dried over anhydrous calcium chloride in a vacuum chamber for 24 hours before transferring it to a tight sealing storage bottle. After 24 hours of drying the product weighed 222,5g meaning it was still too heavy. After an additional day of drying 205,6g of mercuric oxide were left in the container (and 8,5g were next to the container due to boiling under a vacuum).

HgSO4 + 2 NaOH -----> Na2SO4 + HgO + H2O

Theoretical yield: 1mol; 216,59g
Actual yield: 214,1g (98,9%)

A high yield can be expected due to poor water solubility of the product. If washed thoroughly with distilled water and heated for a long time it might also have a high purity. Depending on the addition speed of the sodium hydroxide solution yellow or red mercuric oxide can be obtained. Slow addition (over the course of 20 minutes in 50ml batches) lead to the production of red mercuric oxide, a friend claimed fast addition lead to the production of the yellow form. This claim was not investigated any further. The mercury(II) oxide produced from this procedure might either be contaminated with a small amount of basic mercury sulfate because a yellow powder was left behind after dissolving it in acetic acid or it contains yellow mercury oxide too. The fact that the yellow powder dissolved in hydrochloric acid but not in more acetic acid leads me to the conclusion that this yellow solid was indeed basic mercury sulfate.

We also have a video of the entire procedure:

And here is a picture of the product:

HgO.png - 1.1MB
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[*] posted on 7-6-2022 at 11:48

Try to dissolve small amount of your HgO in HCl and add some BaCl2. If sulfate is present, white precipitate will form.

Welcome to SM btw :).

[Edited on 7-6-2022 by Bedlasky]
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[*] posted on 7-6-2022 at 14:19

So glad to see you revive your account. :)
I have been really enjoying your YT channel lately (as have many others). I was hoping that you would turn up.

Thanks for all that you have been doing.
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[*] posted on 8-6-2022 at 08:53


I appreciate it! Even more interesting projects have been planned for the near future so stay tuned!


Thanks! I´ll give your idea a try tomorrow as I ran out of BaCl2.
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[*] posted on 8-6-2022 at 09:44


Saw your video before I saw this post.

Some of us have been watching your content with considerable interest. Well done.

Phlogiston manufacturer/supplier.

For all your phlogiston needs.
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