LanthanumK's Blog

I have compiled a list of sources for the elements that are available to the amateur chemist. Rhenium will be discussed here.

Rhenium was the last non-radioactive element discovered. The metal itself is extremely dense and lustrous. Rhenium has the highest boiling point of any metal. Rhenium forms perrhenate compounds, which are the most commonly traded form of rhenium. These are much weaker oxidizing agents than the permanganates. Rhenium metal is made by heating the ammonium perrhenate. The rhenium powder is then sintered to form the desirable shape. Rhenium is one of the rarest elements in the earth's crust, with an average concentration of 1 milligram per metric ton in the earth's crust. Rhenium forms a wide variety of colorful and not well-defined compounds in many oxidation states.

In element form: Some thermocouples have tungsten/rhenium alloy in them. Antique GE rhenium flashbulbs have a tungsten/rhenium alloy filament used to trigger the flash.

In compound form: No sources found.

I do not have any rhenium collected at the time of this writing.

I have compiled a list of sources for the elements that are available to the amateur chemist. Tantalum will be discussed here.

Tantalum is an extremely dense, bluish-gray metal. It is named after the king Tantalus, who was submerged in water he could not ever drink and was near fruit he could never eat. Tantalum's behavior of being submerged in acids but never able to dissolve was the reason that it was given the name. Tantalum is a rare and expensive metal, found in niobium ores. It was mistakenly confused with niobium, despite its much higher density, and is difficult to remove from the aforementioned metal. When tantalum is pure, it has excellent physical strength and properties, making it ideal for artificial limbs and fine medical instruments. Tantalum, despite its seeming invincibility, has its weak points; it can be dissolved in hydrofluoric acid or molten hydroxides. Tantalum is primarily pentavalent, which is part of the reason for its inertness. The oxide is a white unreactive substance, difficult to reduce to the metal. It can be made to form compounds to dissolving in molten metal hydroxides or electric arc fusion with other metals, forming a range of tantalates. 

In element form: High capacity (30 mfd or so) tantalum capacitors have a lump of anodized tantalum in the middle. Use hot hydrochloric acid to dissolve any manganese dioxide which may be present. Some expensive medical instruments use tantalum.

In compound form: Motion sensors may contain lithium tantalate as the sensing material.

Here is my sample of tantalum. It is a nugget of tantalum metal with tantalum connector wire, taken from a 22 mfd tantalum capacitor. The green anodized color is visible in certain places.

I have compiled a list of sources for the elements that are available to the amateur chemist. Hafnium will be discussed here.

Hafnium is the first element after the long and boring series of rare earth metals are completed. (Whether you wish to purchase all of them is a matter of your decision, of course, but some of the very similar ones may be skipped.) Anyway, hafnium is a dense (more so than lead), silvery gray transition metal. It absorbs neutrons, making it a harmful impurity in zirconium nuclear fuel casings which must allow the radiation to escape. Therefore, many pains are taken to remove hafnium from zirconium. In most applications, however, most zirconium is mixed with hafnium and vice versa. Therefore, your cubic zirconia is probably also cubic hafnia. Hafnium forms rather low-melting tetravalent compounds; its chloride hydrolyzes in water to form an insoluble hafnium oxychloride, just like most tetravalent compounds. Hafnium is extremely corrosion resistant and does not dissolve in acids or bases. It can burn in air when finely powdered, though, just like titanium. Hafnium finds use in very high-melting alloys, such as those used in rocket nozzles.

In element form: Find a plasma cutter tip at a welding shop and cut off the copper end. You will see a small cylinder of hafnium metal in the center.

In compound form: Cubic zirconia undoubtedly contains some hafnium, as well as most other sources of zirconium.

Here is my sample of hafnium. It is a plasma cutter tip tip.

I have compiled a list of sources for the elements that are available to the amateur chemist. Thulium, ytterbium, and

lutetium will be discussed here. 

Thulium is a typical rare earth metal. Its compounds are pale green to yellow. No sources of it are available to the general public.

Ytterbium is another rare earth metal. Its liquid range from 824-1196 C is the smallest of all metals. Most ytterbium compounds are white and boring. It does form divalent compounds, however, of which the chloride is green. Earthquake meters may contain ytterbium metal to measure the quake, but it is unlikely that they do.

Lutetium is the last of the rare earth metals. It is the rarest and most expensive one. Its compounds are boring and white. Lutetium tantalate is the densest white substance besides thorium dioxide, which is slightly radioactive. There  are no household sources.

Here ends the sequence of little articles about rare earth metals.

Chlorine is a light yellow gas, second from the top in the halogen group (Group 17) on the periodic table. Although it is highly toxic (it was the first poison gas used in World War I), its extremely pungent smell is fair warning. Breathing in small amounts of chlorine is not bad, but larger amounts cause burning of the mucus membranes and lungs.

Bromine, on the other hand, is a reddish liquid that smells similarly, although some say that the smell is less repulsive. Bromine has the additional hazard of being spillable, and liquid bromine evaporates twice as fast as water AFAIK.

Both of these poisonous elements have one property that enables them to be easily, quickly, and completely neutralized. They are strong oxidizing agents. The chloride and bromide ions are harmless, ionic substances in most cases. Therefore, reduction can be used to remove chlorine gas.

For example, if you want to produce some pure manganese(II) solution by dissolving some pure manganese dioxide from a tantalum capacitor in hydrochloric acid, you will produce a large amount of chlorine gas. However, the reaction needs to be heated, so placing it outside on a normal day will slow the reaction very considerably. To prevent gassing yourself in chlorine or bromine gas, you may use a variety of reducing agents. Sodium or potassium metabisulfite, readily available from brewer's shops or chemical supply stores, is a good reducing agent. Mix this with sodium carbonate solution to form a basic reducing solution. Chlorine dissolves easily in a basic solution, forming hypochlorite and chloride. The hypochlorite is easily reduced by the sulfite ions. For a beaker, soak a rag in this solution and place it on top of the beaker. Use the bottom of another beaker if needed to hold the rag down, making sure that all of the chlorine contacts the rag. For a test tube or flask, use a scrap piece of hose (chlorine tends to damage hoses) and lead to a beaker with carbonate-sulfite solution. For a vial, wrap a tissue soaked in the solution around the cap to absorb any produced gases.