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April 25 2012 4 25 /04 /April /2012 15:46

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

 

Terbium is one of the less reactive rare earth metals. It forms trivalent compounds, white and boring. Terbium also forms some divalent and tetravalent compounds, such as terbium (III,IV) oxide, which is black. Terbium compounds fluoresce green brightly. Higher valent terbium compounds are strong oxidizing agents.

 

In element form: Terfenol-D, an alloy used in Soundbug(r) speakers, contains terbium, dysprosium, and iron.

 

In compound form: CFL bulbs and CRT tubes contain green phosphors, most commonly made using terbium doped yttrium oxide or some other terbium doped compound.

 

Here is my sample of terbium. It is a CFL bulb.

 

Fluorescent lamp

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April 24 2012 3 24 /04 /April /2012 13:15

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

 

Gadolinium is one of the more corrosion-resistant rare earth metals. In other words, it does not need to be kept in an ampoule or under oil to prevent rapid corrosion. Its trivalent compounds fluoresce green. Gadolinium compounds themselves, however, are white and boring.

 

In element form: No sources found.

 

In compound form: Some green phosphors contain gadolinium doped compounds.

 

I do not have any gadolinium samples at the time of this writing.

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April 23 2012 2 23 /04 /April /2012 13:13

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

 

Europium is one of the more expensive rare earth metals, because of its high reactivity. For some reason, europium has a reactivity similar to calcium, corroding in moist air and reacting vigorously with water, producing the yellowish hydroxide. Europium is also the lightest rare earth metal. Most europium compounds are whitish but some are yellow; the sulfuric acid solution of europium(III) is reported to be pink.

 

In element form: No sources found.

 

In compound form: Europium-doped yttrium oxide is used to make phosphors in CFL bulbs. Red phosphors contain europium(III), while blue ones contain europium(II). Yttrium vanadata, used as a phosphor in mercury vapor bulbs, also contains a europium dopant.

 

Here is my sample of europium. It is a fluorescent bulb contain europium-doped phosphors.

 

Fluorescent-lamp.jpg

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April 21 2012 7 21 /04 /April /2012 13:17

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

 

Samarium is a rare earth metal that is more corrosion resistant than some of the earlier lanthanides. It is a divalent state, which compounds are strong reducing agents. Samarium(II) iodide is a greenish solid, while most of the trivalent compounds are yellowish or greenish as well. Samarium-cobalt magnets are the second strongest magnets, just behind NdFeB. They have a much greater heat resistance than the neodymium magnets. I tried to extract a pure sample of samarium chloride by dissolving the magnet in acetic acid, but some iron dissolved alongside the rare earths, contaminating the solution.

 

In element form: Samarium-cobalt magnets contain about 15% samarium metal. Mischmetal or ferrocerium contains about 1% samarium.

 

In compound form: No sources found.

 

Here is my sample of samarium metal. It is a complete samarium-cobalt magnet removed from a speaker. The shiny nickel plating is torn off in some areas, exposing the magnetic samarium-cobalt-misc. alloy.

 

Samarium-cobalt-magnet.JPG

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April 20 2012 6 20 /04 /April /2012 13:16

Promethium, being an extremely radioactive and unstable element, is impossible to obtain in pure form. However, some old glow-in-the-dark watches that are radioactive have used promethium as the radioactive element. This is after the radium watches were discontinued and before tritium came into more common use.

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April 19 2012 5 19 /04 /April /2012 18:44

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

 

Neodymium is one of the more reactive rare earth metals. It forms one oxidation state, +3, and has the unique property of color-changing salts. A solution of neodymium chloride, pink in sunlight, may appear light grayish-yellow in fluorescent light. Neodymium oxide ranges from blue to purple to pink.

 

In element form: Neodymium magnets contain about 14% neodymium. Mischmetal has a small amount of neodymium in it.

 

In compound form: "Daylight" incandescent light bulbs often use neodymium oxide to make them bluish (fluorescent) or purplish (incandescent or sunlight) colored. The color change indicates the presence of neodymium.

 

Here is my sample of neodymium. It is a neodymium magnet.

 

Strong-magnet.JPG

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April 18 2012 4 18 /04 /April /2012 20:24

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

 

Praseodymium is one of the more reactive rare earth metals. It forms a trivalent state, like all other lanthanides, that is light yellow-green. Outside of aqueous solution, praseodymium forms some higher oxidation state compounds like the oxide.

 

In element form: Mischmetal contains a small amount of praseodymium. Carbon arc lamps used in film photography contain praseodymium at their cores.

 

In compound form: Some yellow colored glass is colored using praseodymium(III) oxide.

 

Here is my sample of praseodymium. It is a piece of mischmetal.

 

Mischmetal in water

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April 17 2012 3 17 /04 /April /2012 15:37

Magnesium powder or shavings are useful in many experiments in amateur chemistry as a reducing agent. It is also interesting to burn, although repeated burning is discouraged due to the production of harmful UV rays. There are several ways to obtain magnesium in a more finely divided form.

 

Buy it: You can buy magnesium turnings for a relatively low price ($4.50 for 50 grams at AlphaChemicals). However, magnesium powder has some shipping restrictions on it.

 

Knife: When a magnesium bar is scraped, large shavings and flecks of magnesium metal come off. These flecks are useful for reductions and sparkles in pyrotechnic compositions but are less than ideal for thermites or other reactions that need a finely divided form of magnesium.

 

File: I have found a file to be the best way to create small amounts of finely powdered magnesium. Rubbing the magnesium against the file over a piece of paper allows the magnesium to be collected on the paper. It can later be mixed in with any oxidizer and used to create a variety of energetic mixtures.

 

Steel grinder: Electric grinders, though much faster than hand, tend to create air currents that blow most of the superfine magnesium powder away. Powder can be created this way but with a large amount of waste.

 

My first thermite reaction burnt relatively quietly as it used magnesium shavings. The last one, which used a similar oxidizer with magnesium powder, burnt much more rapidly, noisily, and quickly, showing the benefit gained by using powder (generated by a file) instead of shavings.

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April 17 2012 3 17 /04 /April /2012 15:31

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

 

Note: Since the rare earth metals are so similar to each other, I will only include the differences in the description to avoid constant repetition.

 

Cerium is one of the rare earth metals that is more susceptible to aerial oxidation, so it is normally kept under oil or in an ampoule. Cerium forms two oxidation states, a trivalent state which is stable in acidic aqueous solution and colorless under normal circumstances, and a tetravalent state. This state is more stable as a compound, not an ion, and so it is found in basic solution. Cerium dioxide is light yellowish, while other cerium compounds like the sulfate are very bright orange or yellow.

 

In element form: Ferrocerium contains about 50% cerium.

 

In compound form: Cerium dioxide is used as an abrasive and a polish. Some tungsten arc welding electrodes are "Ceriated" with 2% cerium dioxide.

 

Here is my sample of cerium. It is a piece of mischmetal, just like lanthanum.

 

Mischmetal (1)

 

Feel free to view the category "Elements" below for information on obtaining the other elements.

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April 14 2012 7 14 /04 /April /2012 13:19

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

 

Lanthanum is a relatively soft and reactive metal of the rare earth metal group. The first member of its group, it forms white or colorless trivalent compounds, making its aqueous chemistry boring. Lanthanum is found with all the other rare earth elements.

 

In element form: Mischmetal contains about 45% lanthanum, while ferrocerium contains about 30%. Lanthanum alloy is found in the anode of a nickel metal-hydride battery. (Be careful when opening these batteries, risk of fire.)

 

In compound form: No sources found.

 

Here is my sample of lanthanum. It is a piece of mischmetal. The presence of rare earths is indicated by the formation of hydrogen and slimy hydroxides when in contact with warm water.

 

Mischmetal-in-water.JPG

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