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Yttrium2
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Elements with interesting properties
What are some elements with interesting properties?
Besides group 1, and red phosphorous--it sparks with friction right?
Do any other elements behave similarly or react in weird, unexpected ways?
Platinum black reacts with methanol vapor, do any other elements do this?
[Edited on 2-3-2015 by Yttrium2]
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j_sum1
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All of them?
With the possible exception of protactinium and Lutetium and a couple of others.
This thread struggled to get much of a following or a consensus because they are all interesting.
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Yttrium2
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I guess for my third question all of them, um I mean but what about my first question? Like sparking, lighting, type reactivity...
[Edited on 2-3-2015 by Yttrium2]
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Brain&Force
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Cerium sparks like crazy when sandpapered.
At the end of the day, simulating atoms doesn't beat working with the real things...
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Molecular Manipulations
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Helium is the strangest I think, especially for a atom that forms no stable compounds.
Helium is one of only two natural elements that has never been observed bonding to another element in a compound. The other element is neon. Helium
plasma can, however, form temporary excimer molecules with elements including sodium, fluorine and sulfur.
At temperatures close to absolute zero, helium condenses to a liquid with amazing properties – the properties of a superfluid, flowing with zero
friction up and over the walls of containers.
At normal atmospheric pressure, helium does not solidify. At 25 atmospheres of pressure, helium is a solid at 0.95 K. As the pressure rises, the
temperature at which solid helium exists also rises. Helium can be made solid at room temperature if the pressure rises to about 114 thousand
atmospheres: that is a pressure of 1.67 million psi, or 834 tons per square inch. This is over 100 times greater than the pressure at the oceans’
deepest point, the Challenger Deep, which is almost seven miles deep (10 916 meters).
Helium exists in Earth’s atmosphere only because it is constantly resupplied from two sources – decay of radioactive elements on Earth, and
cosmic rays, about 9% of which are high energy helium nuclei.
The helium we buy in cylinders is produced by the natural radioactive decay of radioactive elements in the earth’s crust – principally thorium and
uranium.
Radioactive decay of uranium and thorium produces about 3000 metric tons of helium a year.
Current world production of helium is over 30 000 metric tons a year. (Helium has been accumulating for many millions of years in a few natural gas
fields, therefore we can currently extract more each year than is being created by uranium and thorium decay.)
Helium was discovered in the Sun’s atmosphere before it was found on Earth.
Liquid 3He floats on top of liquid 4He in separate layers. Which makes perfect sense if you think about it.
-The manipulator
We are all here on earth to help others; what on earth the others are here for I don't know. -W. H. Auden
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Oscilllator
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Why's that? Surely they would be soluble in each other. Is 3He so much less dense that 4He that it overcomes the dispersion
forces that normally allow one non-polar substance to dissolve in another?
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Molecular Manipulations
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It's because yes liquid 3 helium is 75% as heavy as liquid 4 helium. Since helium doesn't bond to itself there's no reason for the two to mix. There's
nearly zero friction at that temperature and none of the attraction forces present in solution are present in helium. There's no Van der Waals, no
hydrogen bonding nothing polar at all. Each individual helium atom had is floating around bumping into other "stuff" to which it has zero attraction.
The only deciding factor at play is density, and since 4He is 25% heavier (and probably about 25% more dense, which isn't quite the same), the atom
eventually fall into their rightful place depending on their density. Just like 235 uranium hexafluoride can be separated from 238 because of it's
difference in density. Of course with this the difference is about 1.2% instead of 25%, which makes the latter separate spontaneous rather then have
to go through hundreds of centerfuges.
Quote: Originally posted by Oscilllator  |
Is 3He so much less dense that 4He that it overcomes the dispersion forces that normally allow one non-polar substance to
dissolve in another? |
There is almost no London dispersion force in helium or any noble gas. This is why helium's boiling point is so low, it has no attraction to it self
(practically).
See this
| Quote: |
All molecules experience intermolecular attractions, although in some cases those attractions are very weak. Even in a gas like hydrogen, H2, if you
slow the molecules down by cooling the gas, the attractions are large enough for the molecules to stick together eventually to form a liquid and then
a solid.
In hydrogen's case the attractions are so weak that the molecules have to be cooled to 21 K (-252°C) before the attractions are enough to condense
the hydrogen as a liquid. Helium's intermolecular attractions are even weaker - the molecules won't stick together to form a liquid until the
temperature drops to 4 K (-269°C).
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[Edited on 2-3-2015 by Molecular Manipulations]
-The manipulator
We are all here on earth to help others; what on earth the others are here for I don't know. -W. H. Auden
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blogfast25
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Correctomundo.
Pa: in 1961, the UK Atomic Energy Authority extracted 125 g of 99.9 % pure protactinium from 60 tonnes of spent uranium fuel elements. ('Nature's
Building Blocks', John Emsley, ISBN 0-19-850340-7) Not interesting, you say? 
[Edited on 2-3-2015 by blogfast25]
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Molecular Manipulations
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Some better exceptions are berkelium and einsteinium:
| Quote: |
There is currently no use for any isotope of berkelium outside of basic scientific research. |
| Quote: |
There is no use for any isotope of einsteinium outside of basic scientific research aiming at production of higher transuranic elements and
transactinides
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[Edited on 2-3-2015 by Molecular Manipulations]
-The manipulator
We are all here on earth to help others; what on earth the others are here for I don't know. -W. H. Auden
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careysub
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Another interesting fact about protactinium is that it is one rare actinide that can be obtained in visible quantity by a motivated hobbyist, who
knows how to safely handle uranium ore. In equilibrium, for each 3 grams of natural uranium, there is 1 microgram of protactinium. So if you collected
and processed 2 kg of 15% ore, you could obtain 100 micrograms: not a lot, but enough to make a visible speck in an ampoule.
Its emissions are similar to Am-241, an alpha emitter with weak gammas that are largely attenuated by a glass tube wall.
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blogfast25
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MM:
Hmmm... these superheavies are 'close' to the 'beach' of the Island of Stability:
http://en.wikipedia.org/wiki/Island_of_stability
Careysub:
You may be stretching the definition of hobbyist here. Just think about the mountain of low level radioactive waste one would be generating.
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blogfast25
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Definitely an interesting element: Flerovium
http://en.wikipedia.org/wiki/Flerovium
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DraconicAcid
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There's enough of London dispersion forces to get the gas to liquify at that temperature. There is a very good reason for them to mix- entropy. it's
surprising that the difference in density is high enough to compensate for that.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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careysub
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Perhaps, but we have some very motivated hobbyists here that have accomplished some quite remarkable things.
Developing safe and responsible procedure for processing and disposing is part of the challenge.
But extracting Pa from 2 kg of ore may not be as bad as you imagine.
Pa is stably soluble in strong HCl (7N or greater), without an oxidizer uranium will not be extracted, and radium (present as insoluble sulfates) will
not be extracted. Pa at trace levels can be 100% removed from the HCl by tributyl phosphate. After that point you are dealing with microchemistry.
So with a simple muriatic acid leach of finely powdered ore, you may produce as the principal waste the original ore and some liters of HCl, which
can be evaporated to dryness. Not exactly a mountain, and not sure that it presents more of a problem than just having the ore in the first place.
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Molecular Manipulations
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Which means what
exactly? "That temperature" is only 4K, which implies there's barely any London dispersion forces. Did you think that it is possible for something to
not liquefy?
| Quote: Originally posted by DraconicAcid | | There is a very good reason for them to mix- entropy. it's surprising that the difference in density is high enough to compensate for that.
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How is entropy a good reason for them to mix? Water and gasoline have more attraction for each other than any given liquid helium atom to another, and
gasoline's density is closer to water than 3 helium is to 4 helium. (gasoline = 80.3% water's density vs. 3 helium's 75% of 4 helium). Yet gas floats
on water.
-The manipulator
We are all here on earth to help others; what on earth the others are here for I don't know. -W. H. Auden
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DraconicAcid
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| Quote: | | Which means what exactly? "That temperature" is only 4K, which implies there's barely any London dispersion forces. Did you think that it is possible
for something to not liquefy? |
If there were no London forces, it wouldn't liquify at all. Period.
| Quote: | | How is entropy a good reason for them to mix? Water and gasoline have more attraction for each other than any given liquid helium atom to another, and
gasoline's density is closer to water than 3 helium is to 4 helium. (gasoline = 80.3% water's density vs. 3 helium's 75% of 4 helium). Yet gas floats
on water. |
That's because water has a much greater attraction to other water molecules than they do to alkane molecules.
The attraction between a molecule of carbon tetrachloride and a molecule of benzene is much weaker than the attraction between a water molecule and a
benzene molecule, but carbon tetrachloride and benzene are miscible, despite the greater difference in density.
London forces will not cause two substances to mix. Entropy will cause them to mix; London forces (and other such attractions) can prevent mixing
from happening.
[Edited on 2-3-2015 by DraconicAcid]
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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mayko
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The premise of this thread reminds me of an old joke about mathematical logic:
Theorem: All natural numbers are interesting.
Proof: Zero is interesting - so interesting, in fact, that it was a heretical notion in Western Europe for a while! One is interesting: it's the only
number that's neither prime nor composite. Two is interesting; it's the only even prime.
Suppose that there were numbers which were not interesting. Then, in particular, there would be a smallest non-interesting number. And that, in
itself, would be pretty interesting! QED
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blogfast25
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| Quote: Originally posted by careysub |
Perhaps, but we have some very motivated hobbyists here that have accomplished some quite remarkable things.
|
No one has actually done it here though. Or at VersuchsChemie.
Extracting Pa from uranium ore with 7 N HCl would require the ore to be very finely crushed, no sinecure if you want to avoid radioactive dust. 2 kg
is quite a bit for a bench hobbyist.
At such low levels radiological identification would be needed during extraction and purification (Pa being hardly the only element present in such
ores and soluble in strong HCl), requiring radiometrical equipment and know how.
'Nothing is impossible', of course but I can't see any hobbyist do this anytime soon.
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Cou
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All of the lanthanides are boring to me... they are all the same, grey metals with very similar chemical properties. No wonder people used to think
all the lanthanides were one element.
I like chlorine because it reacts with so many things. Fill a flask with chlorine, and any metal you heat up with a bunsen burner and stick in there,
will have some kind of interesting reaction to watch. It forms compounds with every elements except noble gases.
[Edited on 3-3-2015 by Cou]
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careysub
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| Quote: Originally posted by blogfast25 | | Quote: Originally posted by careysub |
Perhaps, but we have some very motivated hobbyists here that have accomplished some quite remarkable things.
|
No one has actually done it here though. Or at VersuchsChemie.
Extracting Pa from uranium ore with 7 N HCl would require the ore to be very finely crushed, no sinecure if you want to avoid radioactive dust. 2 kg
is quite a bit for a bench hobbyist. |
True, but that part at least has been done by a hobbyist:
https://carlwillis.wordpress.com/2008/02/20/uranium-chemistr...
He works with more than 2 kg at a time.
Extended ball milling in a closed mill will powder quite finely, and wetting the product keeps dust from aerosolizing pretty well (but wear a
respirator, for sure).
He was not extracting Pa specifically, but was going after the uranium.
| Quote: |
At such low levels radiological identification would be needed during extraction and purification (Pa being hardly the only element present in such
ores and soluble in strong HCl), requiring radiometrical equipment and know how.
'Nothing is impossible', of course but I can't see any hobbyist do this anytime soon. |
Right, this is one of the hardest parts in being successful - an alpha spectrometer would be handy. And this is not the first project you would
undertake in radiochemistry.
Still, it was identified by Fajans and Gohring in 1913 with very primitive equipment, and without the advantage of any knowledge of its chemistry. The
techniques used to isolate by them, and Grosse (who prepared a pure compound in 1927), and by Mound Laboratory and the UK AEA to produce gram
quantities are public information.
No amateur has ever done this, for sure. But it is at least in the realm of the possible. It is the rarest natural actinide for which recovery of in
any visible amount can be contemplated.
[Edited on 3-3-2015 by careysub]
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j_sum1
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| Quote: Originally posted by Cou | | All of the lanthanides are boring to me... they are all the same, grey metals with very similar chemical properties. |
What's not to like about lanthanides?
Pick any physical property and plot it against atomic mass and you have a remarkably linear low gradient line. So yes, they are hard to separate.
But that is interesting in itself and has given rise to some remarkably clever ideas attempting to extract them. Witness the efforts in these boards
to isolate neodymium and other lanthanides.
But if you look beyond physical properties you really have some fun. For a start you get a large number of stable oxidation states and some really
pretty-coloured salts.
But if pastel hues are not your thing then there are other intriguing optical properties. Use in lenses and other optical devices. Eu as phosphors
in old tv screens and other weirdities.
If that is not enough for you, the La series demonstrates some bizarre magnetic properties. Ho is for example the strongest paramagnetic element.
That has got to count for something.
So if interesting to you means not a grey metal then fair enough. Strike off most of the table. But if interesting means something else then the La
series is pretty much the jackpot.
(Disclaimer – Lutetium is probably the lanthanide equivalent of zinc in terms of boringness. Stuck on the end of the series and missing out on all
of the fun. Damn full subshell. But then I have never actually seen it and haven't heard of any applications so what do I know. For all I know it
might form a salt that is superconductive to light and has zero opacity.)
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diddi
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Lu is not boring cos it is hard to purify and is expensive and looks might nice in my weighing bottle 
Beginning construction of periodic table display
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neptunium
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| Quote: Originally posted by blogfast25 |
At such low levels radiological identification would be needed during extraction and purification (Pa being hardly the only element present in such
ores and soluble in strong HCl), requiring radiometrical equipment and know how.
'Nothing is impossible', of course but I can't see any hobbyist do this anytime soon. |
half way there...
http://www.sciencemadness.org/talk/viewthread.php?tid=27963&...
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blogfast25
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Very interesting thread. But 'half way there'?
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neptunium
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radiological identification ...
oh and
http://www.sciencemadness.org/talk/viewthread.php?tid=32374&...
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