Rhenium & Iridium
Two amazing elements that really exist.
You might think these are imaginary elements, like lathium or dilithium crystals, but rhenium and iridium are real. You can find them on the periodic table. Rhenium is extremely dense and very heavy. Only platinum, iridium and osmium are denser. It is so rare it costs $11,000 per kilo, and makes up no more than four parts per billion of the Earth’s crust. Rhenium was the last naturally occurring stable element to be discovered and is among the ten most expensive metals on earth.
Rhenium diboride (ReB2) is an extremely hard compound. It can actually scratch diamond, giving it a higher than 10 rank in the Mohs scale of mineral hardness and making it one of the three hardest substances known to man – the other two being ultrahard fullerite and aggregated diamond nanorods.
Rhenium was first identified in 1925 in Platinum ore and the mineral columbite. However, it was so expensive to extract, it was abandoned and ignored until 1950 when it was alloyed with molybdenum and tungsten.
In appearance it is a silvery-white metal. Mixed with other alloys it is used in jet engines as it can withstand the heat and pressure and is the most efficient material. About 35 kilograms are needed to construct one Jet engine. Obviously, with this usage, one would not be surprised to learn it has one of the highest melting points, exceeded only by tungsten and carbon. It has the widest range of oxidation states of any known element.
It’s usual commercial form is a powder, but it can be pressed in a vacuum or hydrogen atmosphere into a shape. Besides it’s use in jet engines it is also used in platinum-rhenium catalysts which make lead free high octane gasoline. Chile has the largest reserves of this mineral. However, the total world production is just about fifty tons a year.
Another very important and barely known element is Iridium which resembles Rhenium. It is a high-strength alloy that can withstand high temperatures and occurs in natural alloys with platinum or osmium. It’s claim to fame is that it is the most corrosion-resistant element known.
Further, Iridium has a particular place in history; it is believed the asteroid which hit the Earth about sixty five million years ago was made of Iridium.
The temporal border between the Cretaceous and Tertiary periods of geological time, was identified by a thin stratum of iridium-rich clay. This is believed to be of extraterrestrial origin. Iridium is used in high-temperature apparatuses, electrical contacts, and as a hardening agent for platinum. One of its actual uses is in supercolliders in the production of antimatter, specifically antiprotons.
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9 Responses to “Rhenium & Iridium”
On June 20, 2008 at 11:59 am
WOW, anyone who reads this article just forget what you just read, i couldn’t get past the first paragraph because it was all… wrong. Here are a few examples dilithium = 2-lithium! rhenium’s density if 21.02 g per mL, a human tooth is less than a mL in volume!!! WHO WROTE THIS?!?!?!
On June 20, 2008 at 2:51 pm
1) there are no such things as dilithium crystals…they exist
in the Star Trek universe.
2) Rhenium is extremely dense. You may check out the ‘weight’
of a tooth sized piece of pure Rhenium on any site you google.
As to the actual ‘weight’ you might have to translate kilograms
into pounds to understand.
On June 25, 2008 at 12:18 pm
Wow, it platinum is heavier than Rhenium, I must be much stonger than I think I am. I have a wedding ring made of platinum and I seem to have no trouble carrying it around (and it’s about tooth-sized). Oh no, wait, you are wrong, but your name is appropriate.
On June 25, 2008 at 5:44 pm
I hate to break it you, Just Me, but your ring is not pure platinum. Alas. You could go to wikipedia if you like, and
read more about rhenium, if you want. It’s free.
On August 19, 2008 at 4:11 pm
My God, use your brain
Density (used Matweb.com)
Silver 10.491 g/cm^3
Gold 19.32 g/cm^3
Rhenium 21.03 g/cm^3
Platinum 21.45 g/cm^3
Iridium 22.65 g/cm^3
First you could answer this by ratio, a silver ring of the same volume would wt. ~ half of a ring made of pure Rhenium. If someone states a ring of rhenium wt in at 10 lbs, that would imply a ring of silver must wt in at 5 lbs.
Second, A normal wedding band has about the same volume of material as a US Quarter. Diameter = 24.26 mm Thickness = 1.75 mm , as stated on wikipedia. Calculating volume Pi*R^2*H give 808.93 mm^3 or .809 cm^3. For the argument sake round up to 1 cm^3 then we can look at the density given above as our wt of we ring respectivly.
~Wt of an avg ring
Silver 10.491 g or 0.023 lbs
Gold 19.32 g or 0.04259 lbs
Rhenium 21.03 g or 0.04636 lbs
Platinum 21.45 g or 0.047289 lbs
Iridium 22.65 g or 0.049935 lbs
Keeping with our selected volume of a US quarter (@ ~ 1cm^3) a 10 lbs ring would have the same volume as (10lbs / 0.04636 lbs) = 215.7 Quarters. Well that’s just my 2 cents, or I guess my 5392.5 cents worth.
On August 20, 2008 at 1:52 pm
Remember we are dealing with a pure substance…
i.e. the diff. between one of those gold bars
at Fort Knox and the chain around your neck.
On August 21, 2008 at 6:44 pm
The only ring that is really effects is the gold ring. Which must have more additives to strengthen it. Platinum normally has Iridium added for strength but that is only about 10%, thus a real Platinum (and Iridium) ring would have a density of ~ 21.57 g/cm^3 rather then a pure platinum ring which would have the stated 21.45 g/cm^3, not much of a difference. So to very close approximations everything above still holds.
On October 7, 2008 at 10:37 pm
I cant carry my ring, its too heavy
On September 12, 2009 at 3:07 pm
I feel so sorry for people who don’t understand that their jewelry is not 100% whatever. This stuff is heavier than lead.
Try picking up a Lead battery from out of your car, and realise it isn’t 100% lead. Just part of it. A wedding band
doesn’t even have a full ounce of gold in it…a few grams
mixed. I’ve been to expos where these metals are displayed
and their weight astounds
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