Requirements

• Distilled Water
• Iron
• Cesium Sulfate (or Cesium Chloride, Cesium Bromide, Cesium Iodide, Cesium Nitrate, Cesium Carbonate, Cesium Hydroxide)
• Hydrogen Peroxide (30% or lower)
• Sulfuric Acid (44% or lower)
• Sodium Sulfate / Potassium Sulfate
• Large heat-resistant plastic / glass container (2 liters or more)
• Open space or laboratory with fume hood
• Protective gear (neoprene rubber gloves, protective goggles, lab coat)
• Fishing Line

Synthesis and Crystal Growth Procedure

Begin by wearing protective gear (neoprene rubber gloves, protective goggles, lab coat). If possible, wear a respirator as well. Make sure that you have a working fume hood or access to the open space outside a building, where you can safely conduct the experiment.

Prepare saturated aqueous solutions:

• 50 grams of Cesium Sulfate (or any other Cesium salt of your choice, any of them will work for this synthesis)
• 100 grams of Sodium Sulfate / Potassium Sulfate (Sodium Sulfate is preferred because Sodium Iron(III) Disulfate Dodecahydrate byproduct is too soluble to contaminate our product, but Potassium Sulfate is also OK)

Then take a large heat-resistant plastic / glass container, place it in a ventilated area. Put 15 grams of Iron inside your container. Add 150 ml of 44% Sulfuric Acid and 100 ml of 30% Hydrogen Peroxide (or recalculate for your lower concentrations). DO NOT USE MORE CONCENTRATED REAGENTS - THE REACTION WILL GO OUT OF CONTROL. The reaction will start to proceed vigorously. Add the Sodium Sulfate / Potassium Sulfate solution. Wait for the reaction to settle down and then add the Cesium salt solution. There is a significant risk of toxic gases such as Bromine / Chlorine / Nitrogen Dioxide / etc. evolving - depending on the Cesium salt you are using. You should minimize the risk by adding the Cesium salt solution at the very end. IF TOXIC GAS RELEASE HAPPENS (YOU WILL NOTICE COLORED YELLOW/RED SMOKE OR PUNGENT ODOR) - HOLD YOUR BREATH AND LEAVE THE AREA IMMEDIATELY. DO NOT RETURN TO THE AREA IF GAS IS VISIBLE OR CAN BE SMELLED

For reference, the reactions involved are as follows:

After the reaction is finished, leave the system to sit in the ventilated place for at least 24 hours (to let dissolved toxic gases escape). After that, place the solution in a cold place, if possible (DO NOT USE YOUR FRIDGE OR ANY OTHER PLACES THAT CAN BE CONTAMINATED BY TOXIC GASES). After some time, a crystalline precipitate will form. That is your Cesium Iron(III) Disulfate Dodecahydrate. Collect it and recrystallize in Distilled Water (dissolve the product in the minimal amount of hot water. After 24 hours, collect the precipitate). Then you can prepare a solution of it to grow crystals (dissolve the product in hot water and let it cool). Add a few drops of Sulfuric Acid to prevent hydrolysis (solution will turn from brown to yellow)

Insert a Fishing Line into the solution and leave the solution undisturbed until seed crystals begin to form on the Fishing Line. Once the crystals reach a suitable size, carefully remove excess crystals so that only one or two remain attached to each line. Transfer the saturated solution into a clean vessel and collect any residual precipitate (which may be redissolved to produce additional solution), and place the Fishing Line with the selected crystals into the fresh solution to continue growth. Inspect the crystals periodically and remove any new growth that forms on the line to prevent unwanted fusion with the main crystal. If crystals do not form directly on the Fishing Line, you can tie a crystal to the line, but that is usually harder.

After approximately one to two months, large, stable crystals will form. Carefully detach the crystal from the Fishing Line. Cesium Iron(III) Disulfate Dodecahydrate is stable under normal atmospheric conditions; therefore, no protective coating (such as nail polish) is required.