What element is denser?

[Blown_Injected]

I thought I could figure what type of shot is heavier by just looking at the PT of Elements. But after reading this thread:
http://boards.straightdope.com/sdmb/showthread.php?threadid=226877
I see my chemistry classes are fading fast after 15 years.

No more lead shot. Steel is what replaced it, but to try to get the performance of lead with a nontoxic material, there is now Bismuth and tungsten shot.

How does the weight/density of lead, bismuth, and tungsten measure up? Looks like Bi is it???

TIA

[Desmostylus]

Steel 7.9 g/cm[sup]-3[/sup]
Bismuth 9.8 g/cm[sup]-3[/sup]
Lead 11.4 g/cm[sup]-3[/sup]
Tungsten 19.3 g/cm[sup]-3[/sup]

[Desmostylus]

Oh, and depleted Uranium only has a density of 18.9 g/cm[sup]-3[/sup].

So Tungsten is not only more dense than Bismuth, it’s more dense than the DU that some are fond of firing.

[Blown_Injected]

Thank you!

I hope there is some good reason for using it - seems like tungsten would be much safer for the guys on the back side of the gun - don’t believe it maters much for the guys on the other end.

[Blown_Injected]

Thank you!

I hope there is some good reason for using it - seems like tungsten would be much safer for the guys on the back side of the gun - don’t believe it maters much for the guys on the other end.

[Q.E.D]

The king of density os osmium at 22.4 g/cm[sup]3[/sup].

Desmostylus, what is up with writing g/cm[sup]-3[/sup]? You either write g[sup].[/sup]cm[sup]-3[/sup], or g/cm[sup]3[/sup].

[DreadCthulhu]

According to this site: http://www.nato.int/du/docu/d000500e.htm
they use depleated uranium instead of tungsten because it holds its shape better, and tends to “self sharpen” when it hits a target, unlike tungsten, which mushrooms. Also DU(being a waste product from other manufactoring) is much cheaper than tungsten, and the DOE can practically give it away to weapons makers, though the handling cost are greater than with tungsten.

[Q.E.D]

*Originally posted by Q.E.D. *
The king of density is osmium at 22.4 g/cm[sup]3[/sup].

Further research seems to show that iridium, at 22.65 g/cm[sup]3[/sup], is now considered the most dense element. Somehow, I think iridium shot would be prohibitively expensive.

[Blown_Injected]

Man, I wish I could remember everything I read on TSDMB!

[Desmostylus]

*Originally posted by Q.E.D. *
**Desmostylus, what is up with writing g/cm[sup]-3[/sup]? You either write g[sup].[/sup]cm[sup]-3[/sup], or g/cm[sup]3[/sup]. **

It’s what happens if you hit the return key when the cursor isn’t where it’s supposed to be.

*Originally posted by Q.E.D. *
The king of density os osmium at 22.4 g/cm[sup]3[/sup].

*Originally posted by Q.E.D. *
Further research seems to show that iridium, at 22.65 g/cm3, is now considered the most dense element.

It’s more complicated than that.

http://www.theodoregray.com/PeriodicTable/Elements/077/index.s7.html

Which is the most dense element, osmium or iridium? That honor has changed hands a couple of times over the years. How, you might ask? Because measuring the density of a pure element isn’t nearly as straightforward as you might think. For one thing, it can be different for different crystalline forms (allotropes) of the same element. For example, diamond is much denser than graphite: Which is the true density of carbon? Both. In the case of metals, it may be impossible to grow single crystals, so you’re measuring the density of a polycrystalline mixture, and the density may depend on details of how the material cooled. Minute impurities can also have a big impact on the density.

So, as measurements and purities were refined over the years, the current best values of osmium and iridium kept changing, and that’s how they traded places as most dense of all. I solved this dilemma by only having room to engrave three decimals places of the density, and to three decimal places their density is identical, so I didn’t have to pick sides.

[Q.E.D]

*Originally posted by Desmostylus *
**It’s what happens if you hit the return key when the cursor isn’t where it’s supposed to be. **

Uh huh. Well, that’s as good an excuse as any.

*Originally posted by Desmostylus *
**It’s more complicated than that.

http://www.theodoregray.com/Periodi...7/index.s7.html**

Apparently so. One of them must be the most dense, though. They cannot both have precisely the same density.

[Desmostylus]

*Originally posted by Q.E.D. *
**One of them must be the most dense, though. They cannot both have precisely the same density. **

Why can’t they?

In any case, they have different thermal expansion coefficients.

Osmium: 4.57x10[sup]-6[/sup] K[sup]-1[/sup]
Iridium: 6.40x10[sup]-6[/sup] K[sup]-1[/sup]

Iridium expands and contracts more with temperature than Osmium does.

Lets say you do a density measurement at 25 [sup]o[/sup]C and get the following results:

Iridium: 22.41 g/cm[sup]3[/sup]
Osmium: 22.40 g/cm[sup]3[/sup]

If you heated them both by about 80 K, their densities would match, at about 22.375 g/cm[sup]3[/sup].

If the initial results were reversed, then their densities would match if you cooled them by about 80 K, at which point the density of both would be 22.434 g/cm[sup]3[/sup].