Chemical structure Top: Iron-II-oxide Bottom: Iron-III-oxide 3D Structure Top: Iron-II-oxide Bottom: Iron-III-oxide
Structure make-up Short hand chemical structure
Iron-II-oxide
Ferrous oxide forms a black powder with a melting point of 1360 Celsius. The powder readily oxidizes when heated in air forming ferric oxide. The powder can absorb carbon dioxide from the air, and is a strong base. It is insoluble in water and the usual solvents.
Iron-III-oxide (ferric oxide)
Iron-III-oxide forms a red to reddish to blood red powder with varying chemical composition. It is insoluble in water, and the usual solvents, and iron-III-oxide that has been roasted for several hours is almost insoluble in acids. Iron-III-oxide is a major ingredient in thermite and other incendiary agents.
Method 1: Preparation of Iron-II-oxide and Iron-III-oxide from iron nails or rods using an
open cell and pickling salt
(By-products from reaction: Hydrogen gas)
Materials:
1. 100 grams (3.5 oz.) of pickling salt 3. Two iron nails, or rods ranging 5 to 12 millimeters in diameter (0.19 inch to 0.47 inch) by 6 to 9 inches in length 2. 400 milliliters (13.5 fluid oz.) of water 4. 750 milliliters of warm water (25.3 fluid oz.)
Summary: Iron-II-oxide can be readily prepared by first, electrolyzing a solution of pickling salt using iron electrodes. During the
electrolysis process, a messy precipitate of mixed hydrated iron oxides is formed. Thereafter, this precipitate is collected by filtration, and then dried. The dried messy mass is then dried in a desiccator under mild heat for 12 to 24 hours to facilitate formation of the iron- II-oxide. For the preparation of iron-III-oxide, the same electrolysis process is used to form the initial messy mass, and this mass is then collected by filtration and dried in the usual manner. However, instead of drying this mass in a desiccator, it is roasted at high temperature for several hours to facilitate formation of iron-III-oxide, which is formed by the oxidization of the iron-II-oxides.
Hazards: use caution when using electricity, and do not touch both electrodes at the same time while the electricity is on. Procedure:
Step 1: Formation of mixed hydrated iron oxide slag using an open electrochemical cell.
Set-up the apparatus illustrated below, and then add and dissolve 100 grams (3.5 oz.) of pickling salt into 400 milliliters (13.5 fluid oz.) of water, and then put in place two iron nails, or rods ranging 5 to 12 millimeters in diameter (0.19 inch to 0.47 inch) by 6 to 9 inches in length, and then place the positive and negative clamps of your power supply onto the corresponding nails, and then begin the electrolysis. Use a current of 6 to 12 volt at 2 to 6 amp. Note: a simple house hold car battery charger is well suitable as a power supply. During the electrolysis, a multi colored precipitate of mixed hydrated iron oxides will precipitate. The color will vary from green to orange-like. Hydrogen gas will be steadily evolved from the cathode so use proper ventilation and do not allow the gas to accumulate. The iron anode will slowly corrode and disappear. The electrolysis process can be slow, and can take any where from 12 to 16 hours to complete, depending on the thickness of the iron nails or rods. Thick nails or rods will take much longer to consume as the electo-chemical reaction proceeds. Thin iron nails or rods should be avoided as they will corrode much faster. After the
electrochemical reaction, or after the desired amount of time has passed, remove the power source, and then filter-off the precipitated messy mass, using preferably vacuum filtration. After the filtration process, wash the filtered-off mass with three 250-milliliter portions (three 8.4 fluid oz. portions) of warm water, and then vacuum dry or air-dry the filtered-off mass. Note: the iron nails or rods should be as pure as possible, and steel, galvanized, and plated iron nails or rods should be avoided to avoid the formation of other metal impurities.
Figure 061. Set-up for the preparation of mixed hydrated iron oxides.
Step 2A: Preparation of iron-II-oxide
To prepare basic iron-II-oxide, the dried mixed hydrated iron oxide mass (prepared in step 1), needs to be dehydrated under suitable conditions. To do this, place the dried mass into a desiccator, filled with concentrated sulfuric acid, and then gently heat the dried mass to about 50 to 60 Celsius for 12 to 24 hours. After the heating process, the final product should be a jet-black fine mass, which can be ground into a powder if desired. The final dried product should be kept in airtight containers.
Step 2B: Preparation of iron-III-oxide
To prepare iron-III-oxide, all you need to do is place the dried mass of hydrated iron oxides (prepared in step 1) into a crucible and then heat at 600 to 800 Celsius using a typical Bunsen burner for about 3 to 4 hours. During the heating process, water is volatized and removed, and the iron oxides are oxidized to iron-III-oxide forming a red powder. After the roasting process, the iron-III-oxide is cooled, and then stored in any suitable container. This iron-III-oxide can be powdered and used in thermite compositions, or pyrotechnics, or used as a catalyst for the oxidation of various gases.