h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: Melting Points of Common Metals - A2260063
Author: FordsTowel - U227087

Not quite ready for Peer Review, but suggestions are still welcome.

Hmm, a bit bare of content for the moment... whilst the info could be useful I think the entry as a whole is missing reading matter...

How about a brief explanation of what a metal actually is for a start?


Whisky

Just the sort of intro idea I was searching for!

Thanks

Hey there, Whisky,

I hadn't really considered this material for a full-blown text bit, but I think it did add something.

Thanks again for the push,

Nice intro.

I would remove Phosphorus, Silicon and Carbon from the table as they are not usually considered to be metals.

Plus. Alloys can have melting points way below the melting points of the two original metals. This phenomenon is widely used in metallurgy and the ratio with which to mix the two metals to give the lowest melting point is called "eutecticum" or something similar (I am a non-English chemist, and don't have my dictionaries at hand, sorry.)

May I contribute with some more (the remaining) melting points, so this list is complete?

Tomorrow, OK?

HELL

Fascinating! And quite welcome.

I'd be glad to include other materials, though I am loathe to delete the other substances for which one might reasonably looking for melting points.

I was not thinking of this as exclusively a metalurgical table, but I'd be more than happy to include you as a contributor if you choose to offer additional data; and particularly if you can come up with that word and an outline of the process.

Completion is a good thing

The magic word is 'eutectic', which is both a noun and an adjective, connoting as easy as possible to melt. There is a property of being easy to melt, called eutexia. All this from greek 'eu'=well and 'tekein'=to melt.

The constituents of an alloy are a eutectic(adjective) mixture when the melting point is as low as possible, and a solder may be called a tin/lead eutectic(noun) when the proportions of tin and lead give the lowest melting point.

It may also be of interest to FordsTowel in jewellery work that most tin/lead solders available in fine wire form are NOT eutectics, but formulated with other properties in mind. The solder known as HMP has a deliberately High Melting Point, and is typically used in electrical equipment where components which have high dissipation, and normally run hot, have soldered connections.

Yes, Hairy, it's a word all right!

All I have to do is say it to a coworker and it causes their faces to contort into a confused look! Magic!

I'm glad that you reminded me that solders all have their individual traits, such as the strength and conductance of silver-solder over lead. This whole concept may mean yet another, separate, article.

Meanwhile, would you mind my adding you to the contributors'/researchers' list?

[. . . Speaking of HMP solders, GM produced a new design for a automotive engine generator some years back, and decided to save production costs by moving a controlling circuit board to a position inside the unit. Guess what happened to these hot-running engines, when they were left running and parked up against a fence or wall, when air could no longer pass easily through the radiator?

Surprise! Softened solder and failing circuit boards! Give that release engineer a prize! . . . ]

Well you could go in two ways:

1. Concentrate on metals, adding specific metallurgic aspects (like 'eutectic' mixtures, formation of alloys, and also add some brief stuff like why is it important to know melting points (as Old Hairy noted this is important for electric devices, jewellers etc.)

or

2. Add all other materials and have there a more general list of melting points of elements.

I'd rather vote for 1, because metals are easier to compare among each other, at least as far as melting points are concerned. I think that a comparison between iron and diamond, for example, is a bit more difficult to interpret.

In any case here goes the list of metal melting points (check spelling in periodic table Entry):

Lithium Li 180.54
Sodium Na 97.82
Potassium K 63.60
Rubidium Rb 38.89
Caesium Cs 28.25
Francium Fr 27
Calcium Ca 839
Strontium Sr 768
Barium Ba 710
Radium Ra 700
Scandium Sc 1539
Titanium Ti 1667
Vanadium V 1915
Technetium Tc 2172
Mercury Hg -38.84
Yttrium Y 1523
Lanthanum La 920
Zirconium Zr 1857
Hafnium Hf 2227
Niobium Nb 2468
Tantalum Ta 3000
Tungsten W 3410 (that's the reason it's used in light bulbs)
Rhenium Re 3180
Actinium Ac 1050
Gallium Ga 29.78
Indium In 156.61
Tellurium Tl 303.5
Polonium Po 254
Astatinium At -300

Cerium Ce 798
Praseodymium Pr 931
Neodymium Nd 1010
Promethium Pm 1080
Samarium Sm 1072
Europium Eu 822
Gadolinium Gd 1311
Terbium Tb 1360
Dysprosium Dy 1409
Holmium Ho 1470
Erbium Er 1522
Thullium Tm 1545
Ytterbium Yb 824
Luthetium Lu 1656

Thorium Th 1750
Protactinium Pa 1572
Uranium U 1133
Neptunium Np 639
Plutonium Pu 640
Americium Am 1173
Curium Cm 1345
Berkelium Bk 1050
Californium Cf 900
Einsteinium Es 860

The remaining elements (the heavier trans-urans and synthetic elements) have not been characterised as to the melting point.

They are

Fermium Fm
Mendelevium Md
Nobelium No
Laurentium Lr
and the elements 104-117

Tungsten has the highest melting point and is therefore used in many high temperature electric or electronic devices.

Mercury is famous for being liquid, right and among the common metals (let's exclude the radioactive Astatinium) it's the one with the lowest melting point. Also there is a number of metals that would melt if you place them on your hand, like Gallium (I wouldn't put the remaining metals with a melting point below 35°C on my hand, because they are quite reactive and dangerous)

OK,

later,

HELL

No need to make me a co-author, just trying to help.

Hey there H-e-double toothpicks.

You've got a fine list there!

I could look up the abbreviations easily enough, and could probably throw together a spreadsheet to calculate the conversion of temperatures; but where am I gonna pick up their Specific Gravity numbers and appropriate weights?

There may be some here that you consider more important and common than others. Certainly we cannot go down to the local chemists or hardware store and ask for Einsteinium.

Which elements do you figure to be common enough to warrant inclusion? I want this to be of potential use, and am not too interested in being a pure completeist about it.

I look forward to your picks.

It looks much more like an entry now, FordsTowel.

I have two minor comments only - the bulk of this post is for information only.

You have retained phosphorus, which is dangerous, being both poisonous and highly flammable, and not a metal. Are you thinking of phosphor bronze, which is a metal, an alloy in fact, often used in bearings?

I do not know how much of what follows you would want in the entry, perhaps none, but it slightly disagrees with what you have there now.

Plumbers invariably use what everyone else calls soft solder, but among themselves, that may vary. I think they refer to the solder used for copper piping as hard solder, and the solder used for lead piping as soft solder. This soft solder is the one that solidifies gradually, enabling it to be 'wiped' to mould it into shape. Unless very hot, it does not 'run' when it melts. Soldering lead pipes is quite difficult, and a dying art. In the UK, lead is now illegal for new pipe work and in the solders, which used to be tin/lead, used on copper pipe work. The tin/lead solder melts quickly, and runs well. Some copper pipe joints get the solder to where it is supposed to be by capillary action, which only works with runny solder. To non-plumbers, soft solder covers all the tin/lead compounds (and their modern, lead-free replacments), and hard soldering is brazing or silver soldering. At least, that's my understanding of it all. For most non-plumbing work, plumbing solders are to be avoided. The wire solders tend to be self fluxing, but have very aggressive (acidic) fluxes, and plumbers often use bars of solder, which are are non-fluxed. The fine wire solders commonly used in electronics are usually 'multicore', that is, have built in cores of flux. This flux is designed to be non-corrosive, but is usually washed off anyway in electrical equipment. (Some of what I have said about solder may be out of date, or even plain wrong. I really did not keep up with this when lead was banned from pipe work, and deprecated in general.)

I hope that helps to explain a confusing subject.

It does help clear things up, although it means a bit more research.

Anything that contains lead, that could conceivably come in contact with humans or their food supply, is considered a danger worth avoiding.

It just leaches too easily, and the effects are so cummulative that lead poisoning is hard to spot. And it isn't always entirely reversible.

Thanks for the fodder.

Hello, me again.

First, Correcting Astatine melting point !!!
It's 302 degrees C positive!!!

Second: Ok, you want densities? Here they go (in g/ml, at 20°C)

Lithium Li 0.534
Sodium Na 0.971
Potassium K 0.862
Rubidium Rb 1.53
Cesium Cs 1.83
Francium Fr --
Calcium Ca 1.55
Strontium Sr 2.54
Barium Ba 3.5
Radium Ra 5
Scandium Sc 2.99
Titanium Ti 4.54
Vanadium V 6.11
Technetium Tc 11.5
Mercury Hg 13.546
Yttrium Y 4.469
Lanthanum La 6.15
Zirconium Zr 6.506
Hafnium Hf 13.31
Niobium Nb 8.57
Tantalum Ta 16.65
Tungsten W 19.3
Rhenium Re 21.02
Actinium Ac 10.07
Gallium Ga 5.904
Indium In 7.31
Tellurium Tl 6.24
Polonium Po 9.32 (alpha Po)


Cerium Ce 6.77
Praseodymium Pr 6.77
Neodymium Nd 7.01
Promethium Pm 7.26
Samarium Sm 7.52 (alpha Sm)
Europium Eu 5.24
Gadolinium Gd 7.9
Terbium Tb 8.23
Dysprosium Dy 8.55
Holmium Ho 8.80
Erbium Er 9.07
Thullium Tm 9.32
Ytterbium Yb 6.9 (alpha)
Lutetium Lu 9.84

Thorium Th 11.72
Protactinium Pa 15.37
Uranium U 18.95
Neptunium Np 20.25
Plutonium Pu 19.84 (alpha, 25°C)
Americium Am 13.67
Curium Cm 13.51
Berkelium Bk 14 (est.)
Californium Cf --
Einsteinium Es --

All the best,

HELL

I've just read this entry and I think it's very informative. I am not sure about this, but perhaps a conclusion at the end would be a good idea?

A quick Google search seems to suggest that 'Harry Callahan' said that quote at the beginning.

Great work.

Hi FT. I think your list ought to be in alphabetical order. Typically, it will be used by someone not knowing a melting point and wishing to find it out. Therefore that value is the one thing they cannot search on! Also, it is usual to have the indexed term at the left hand side of the table, not in a distant column. This can be partucularly confusing when the column headers have scrolled up off the screen.

Your description of melting point confuses it with the latent heat required for the process.

Your example of pressure dependence is, confusingly, for a boiling point. Melting point is much less pressure sensitive. Your text is potentially misleading here.

You might include a link to http://en.wikipedia.org/w/wiki.phtml?title=Special:Whatlinkshere&target=Melting_point

If your final version has, as well it might, something to add to the Wikipedia, why not consider offering it to them before giving the BBC the copyright?

toxx

Hiya BB and Toxxin,

Wow, I had nearly forgotten about this piece. I'd meant to get back to it.

I'm temporarily cut off from my usual connection times, so it will be a bit before I can do the proper re-research and re-constructing.

I do, however, appreciate both comments. Good points there. Thanks!