Introduction: Electroplating With Antimony Sulfide Complex Over Steel and Possibly Copper. That Is Light Sensitive to UV.

About: I am a part-time hobbyists biotechnologist with a photonics background. I also have a YouTube channel too. I work full time now.

Hello, fans of SHOE0007.

Here I am going to show you how to plate with Antimony salt. Normally antimony is a very unreactive metal and does not plate well to stuff like copper or steel. However, A mixture of Antimony sulfide in K2S (Potassium Sulfide) does plate well with steel. It results vary dependant on different types of steel.

Antimony metal dissolves in hot 98 percent Sulfuric acid but distilling sulfuric acid at 337 degrees C is extremely dangerous and it vents of SO2 gas and some SO3 (Sulfur dioxide and Sulfur trioxide) as the Sulfuric acid reacts with hot antimony. You need very strong acid that quite hard to find. It often added with Hydrochloric acid 15 percent (30 percent HCl, 47 percent Sulfuric acid) to form a salt Antimony (III) chloride.

Antimony plating is not heard off but possible before using this (Potassium sulfide and Antimony sulfide) the only other option was highly concentrated chlorine gas (Yikes it so toxic), or Aqua Regia (1 part Nitric acid + 3 parts HCl).

Regia but the danger there is Nitric acid, Nitric oxides (NO and NO2) gas plus HCl- Hydrochloric acid fumes while electroplating. This alternative is good. Here a video on if you had Magnesium Nitrate or a Nitrate salt and you added 31.45 percent HCl you could make Aqua Regia.

That one with sulfuric acid and a Nitrate salt.

Here one with HCl.

Yes I show this at the beginning as another Option for Aqua Regia... Just for curiosity only.

Step 1: Materials and Supplies (Including Chemicals).

Here are the chemicals Required.

Antimony Sulfide (Sb2S3)- 99 percent Pottery grade Ebay.

  • 90-94 percent Potassium Hydroxide. Higher the purity the better. If it has Zinc this will ruin your RESULTS. Check Amazon or eBay for Lye.
  • 99-100 Percent Sulfur.
  • 98 percent Sodium metabisulfite or another weak acid salt like Sodium Metabisulfite.
  • 100 percent Magnesium Sulfate for Electrolysis.
  • Sodium oxycarbonate Na2CO3*1.5H20. Cleaning plates.
  • Steel Pipes, Washers, etc ( I recommend stainless steel NOT zinc steel!!).
  • Copper wires. Thick wires

Optional chemicals

Citric acid Pure, Sodium Bisulfate, Potassium bisulfate, etc to make an acid bath for the steel.

Sodium carbonate, Lye (Potassium hydroxide, Sodium hydroxide). After rinsing in hot water to get rid of the acid.

Equipment Needed.

Hotplate or Hotplate with Magnetic stirrer 300-600 deg C and up to 1000 RPM stirring.

Electrical Power Supply (0-9 volts) you can use a cellphone charger with a var control.

Or a 100-500 dollar (0-15 volts, 0-30 volts, and 0-1.5 amps to 0-2 amps) Power supply DC.

Distiller flask 1 L, tubings, 24/40 female to male adapter, and reflux column.

Distillation tubes and Pump (Pond pump, etc or a water pump).

Glass Pyrex bowl or a Ceramic bowl for cooking that can handle max 500 deg C.

A voltmeter or a multimeter.

Step 2: Major Warning About Chemicals and Safety.

Keep in Mind that Potassium Sulfide from Sulfur and Lye heated at 100 deg C for 6 hrs for a few days is toxic and corrosive. Lye is very dangerous so PPE (Gloves, Apron, face shield, etc) must be worn. Antimony sulfide dust is nuisance dust that without a mask (N95) can cause sneezing and asthma in some people.


However normal use and labeling stuff and avoid using acids the risk of making any H2S is very very small. It is next to zero. This precaution must be said here since Hydrogen sulfide (Smells like Rotton eggs) quickly paralyzes your smelling abilities and you can quickly die from it.

Step 3: Distillation of Potassium Sulfide and Antimony Sulfide Complex.

About 180 g of 95 percent Potassium Hydroxide is added to 160 g of 99-100 percent Sulfur. They are weighted out by a 0.1 gram Plus or Minus Error scale up to 500 g digital scale (Not shown). Then quickly they are put with a plastic funnel into a 1 L two jointed flat boiling flask and distillation is set up. An Oil bath with Canola Oil which is good up to 200 degrees C is used.

The temp Never goes past 100 degrees C tho. Rubber hoses to a pump cool the solution. You have to monitor the solution when it heats up. If you are using a reg hot plate make sure it suited for the distillation equipment. Buy the Hotplate and distillation kit. They are around 200 dollars or less. Sometimes there are sales so wait for a Sale on eBay.

Add the 200 grams of the Antimony Sulfide once the distillation of Potassium Sulfide is done. It will in general only partly react. The high heat will form a complex. Altho I said you could distill other ways when exposed to light it converts partly into black oxide K3(Sb2S3) into a hydrate with water and LIGHT and AIR makes this project tricky it is Light sensitive.

A recommendation if you are going to do this is to use a low light setting like a small 40 W lightbulb, not a CFL or Led light and have it partly shielded and only turn it on while adjusting the setting of the temp. If the hotplate gets too high and the condenser gets really hot turn down the heat dial to 3 to 2 or so.

I have kind of learned this the hard way here. This takes careful adaptation of days doing it for 6 hrs a day by reflux. Also due to Lye and K2S, a normal filter paper cannot be used it is too corrosive and these chemicals will eat through the paper instantly!

Step 4: Prep Work for Electroplating.

I found that light and air are key here. Low setting 40 W regular light at least 3-4 meters away from the apparatus. You can use a 100 dollar power supply DC or you can just use a Phone Charger at 9 volts to 12 volts and around 500 mA to 1 Amp.

You will need prob a voltmeter or a multimeter to determine Polarity of the current. So you can determine Negative and Positive that is very important for this project too. The copper also corrodes a bit due to the Lye and Potassium sulfide. This is true if you're just using a Phone charger plug, etc.

The solution will grad change color so a dark room is sort of needed. Here more pictures of the sludge.

Optional you plate some of the material and using a metal pan you bake with the metal with a hotplate near max for 1 hr.

50-100 g of Magnesium Sulfate should be added not Sodium chloride as it may generate chlorine gas.

Step 5: Some Final Results of Plating With Coating and Then Heating.

Here are some coating and plating results. Notice the blue color of the metal. This complex is very unique.

It is not recommended that you should add acid to Sodium Metabisulfite (Na2S2O5) since toxic Sulfur dioxide gas will be released. Please avoid doing this.

Wash the stainless steel washers with a weak acid like citric acid or Sodium bisulfate and use hot water to get a hot solution with a 500 ml beaker. Wait for 1 hr than decant without the metal being poured out and falling out (wash to get rid of any acid).

You can use Lye (NaOH, KOH) or sodium carbonate instead of Sodium percarbonate (also known as Sodium oxycarbonate) and wash overnight and the steel should rust and oxidize.

Put it into the solution for plating and plate this material for 2 hrs checking the solution.

Step 6: Conclusions for Antimony Sulfide Electroplating.

Altho difficult I am pleased when I did this Instructables. Yes, a lot of money and time was invested in it and it is a pain in the ass dealing with light-sensitive chemicals. However the neat color changes and interesting results with steel Only --- it does NOT work with Copper or Bronze or Brass metal is an understatement here.

Keep in mind that the sulfur smell is annoying and it stains your skin blackish yellow so please wear gloves and safety gear as much as possible. Nobody has ever done plating with Antimony since it is really hard and extremely difficult to plate.

I have discovered by ACCIDENT a method of plating with an Antimony salt. It is very unique.