Caroline's weblog
Friday July 21, 2006
Solid State Modeling
Have you ever used a gameboy, a cell phone, a computer? Have you ever admired a diamond ring? These things are made possible by the concepts you will be studying about in this lab. The technology is made possible by the use of semiconductors - this is a atomic material that has properties between a conductor (like iron) and a insulator (like styrofoam). Here is a cool website where you can look at the the unit cell of common semiconductors - such as Silicon (Si), Gallium Arsenide (GaAs), and Zinc Sulfide (ZnS).
Diamonds are also an example of a crystalline solid.
This is a website where you can see the structure of diamond.Diamonds are very hard substances - people can even cut things with them, such as bone!
Speaking of biology now, protein structures are also determined by x-ray crystallography, which is a technique that uses the same theories (bond angles and lengths) as this lab does.
For this lab, it would be wise of you to FOLLOW THE DIRECTIONS CAREFULLY!
The problem that I have seen in the past people having with this lab is that they can not "see" inside their unit cell to determine how many of each type of atom there are inside. If you have this problem, take a layer off, or build another layer so that you can answer the questions properly.
For the post lab one equation that is good to know is for the packing efficiency.
Packing efficiency = (Volume of atoms in one unit cell / Volume of one unit cell) * 100%.
Posted at 12:26PM Jul 21, 2006 by CHRISTIAN, CAROLINE in General | Comments[7]
This is a personal weblog, I do not speak for my employer.
Thats really interesting how closely related are the structures of semi-conductors and diamonds. It makes me wonder what sort of electrical properties diamonds have.
Are diamonds a unique gem in this regard or are precious stones such as rubies, emeralds, and sapphires also in this crystalline sold group?
Also do you know what atoms make up a diamond? Is it made up entirely of Carbon?
I found another cool article about the suspected largest diamond in the universe :)
http://en.wikipedia.org/wiki/BPM_37093
Posted by Wes on July 23, 2006 at 02:20 PM EDT #
I found it interesting that there are that many atoms in a diamond molecule. No suprise that they're so hard after seeing their dense, stable structure. The versatility of diamonds is facinating as well.
Wes's post from wikipedia was quite neat (and actually clicking on diamond from that point has a lot info as well)! A little reminder that our elements aren't Earth bound...
Posted by Kathryn on July 23, 2006 at 06:38 PM EDT #
To answer Wes's questions - Diamonds are actually insulators - they have no electrical properties whatsoever.
I did not actually tell the truth about semiconductors - pure Silicon is actually also an insulator, but to make semiconductors they dope it with elements that have either less or more electrons. This way the electrons can be moving around, and can generate electricity.
Actually other precious gems are also crystalline materials - but they have much more complicated chemical formulas, and more complicated crystalline structures than the ones we will be building today in class.
The reason I think diamond is so cool is because it is made entirely of Carbon.
That was a cool article about the worlds biggest diamond Wes, thanks!
To respond to Kathryn's post - yes Diamonds are supposedly the hardest substance on earth, but your pencil lead is also made entirely of Carbon. Why do they have such different properties? It is because of how the Carbon is put together.
You are correct, diamonds do have a very dense, stable structure!
As too, whether elements are Earth bound or not - think about it, the rest of our galaxy has to be made out of the same stuff as here on Earth! If there was a completely new element out there on some other planet - we would have detected it, or it may have come to earth by now!
Posted by Caroline on July 24, 2006 at 09:32 AM EDT #
most interesting
Posted by Kyle on July 24, 2006 at 10:43 AM EDT #
The whole concept of conductivity is really interesting. I remember Professor Levine in class said that gold of all this is a really good conductor of electricity. I am also wondering if the hardness of diamond comes from the fact that its particles are so tightly packed together. If this is so then why isn't ice which is also a cyrstalline structure not as hard as diamond is. I am pretty sure ice can't cut through bone but diamonds can. I was also wondering about how do diamonds form in nature. I am guessing the formation of diamonds must be a very rare thing because they are so expensive
Posted by Afshin on July 24, 2006 at 11:47 AM EDT #
You are correct - gold is a good conductor of electricity. Most metals are!
The hardness of diamond comes from the way the atoms of Carbon are packed together. They are packed in a specific way together. Ice is not as hard because it melts at a lower temperature, and its molecules are not packed together in such a way.
Diamonds in nature form from Carbon - or coal! It takes high pressure and high temperature to form a diamond. (Remember in Superman, when he makes the diamond from coal in his hand!) Yes, you are correct also that diamonds in nature are rare, and they are expensive.
They also make synthetic diamonds these days, but I am not quite sure how it is done!
Posted by Caroline on July 24, 2006 at 12:17 PM EDT #
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