Need help finding atomic structure images

[hypervalent_iodine]

Well, I appreciate the ego boost, but I'm sure you would have managed to learn at least something without me. If you have any more questions following discussion with your professor and/or during your break, feel free to come back and ask them.

[ben1793]

I have done some more research and also talked to my lecturer before the holidays and found that like you said in the past, some of the materials I have listed are without shape (no crystal structure), did some research and found these were called amorphous, he said from the top of his head he could tell me that polyethelene has no shape, I asked him about the others and he said if he remembers right tungsten does (which was BCC) and quartz crystal does, that is all he knew off the top of his head but he said all he wants is the structure like tungsten which was BCC, he says just show the type of structure for example (BCC, FCC, close packed hexagonal, http://www.askiitians.com/onlinetest/studymaterial_images/1980_Crystal%20system.JPG), I am a bit confused now, I know tungsten and quartz crystal definatly have crystal structure but I cant find any for either quartz crystal or the others (GFRP, silicon carbide, shape memory polymer) are some of these also without shape(amorphous)? Also the tungsten, I did some research and found different forms of the crystal, I think the BCC which I found is alpha but there are also two others beta and delta I think, I found that these are different structures because of the tempreture effecting the structure, what would the crystals look like for beta and delta?(this is just extra knowledge for me )

 

Now from what you said tungsten is made from the same atom not a combination of many so it is a element, the other materials are made from a combination of different atoms so this means they are compounds? how would I draw the atoms for the compounds, for example for silicon carbie(SiC) would I get a silicon atom and carbon atom and draw them with a covelant bond? would the bonds for the materials be different because I did some research and found that there are different bonds, covalent, ionic and metalic bonds from what I read the covalant is where the outer shell electrons are shared, the ionic is when one atom gives another its electron making one positivly charged and one negatively and they attratact and the metalic is where the electrons are free and the posotivly charged atoms all atract to the pool of electrons, is this correct or have I been reading wrong?

 

sorry for asking so many questions, hope it does not bother you, thank you for your help

Edited February 13, 2012 by ben1793

[hypervalent_iodine]

I have done some more research and also talked to my lecturer before the holidays and found that like you said in the past, some of the materials I have listed are without shape (no crystal structure), did some research and found these were called amorphous, he said from the top of his head he could tell me that polyethelene has no shape, I asked him about the others and he said if he remembers right tungsten does (which was BCC) and quartz crystal does, that is all he knew off the top of his head but he said all he wants is the structure like tungsten which was BCC, he says just show the type of structure for example (BCC, FCC, close packed hexagonal, http://www.askiitian...al%20system.JPG), I am a bit confused now, I know tungsten and quartz crystal definatly have crystal structure but I cant find any for either quartz crystal or the others (GFRP, silicon carbide, shape memory polymer) are some of these also without shape(amorphous)? Also the tungsten, I did some research and found different forms of the crystal, I think the BCC which I found is alpha but there are also two others beta and delta I think, I found that these are different structures because of the tempreture effecting the structure, what would the crystals look like for beta and delta?(this is just extra knowledge for me )

 

I think most of this was already mentioned/answered in this thread if you look through it. Did you find out which polymer he wanted for the memory shape and fibre glass? Chances are they are amorphous as well. Whether or not polyethylene is amorpous depends on what type it is, as I said already. LDPE is amorphous, HDPE is not.

 

Yes, there are different forms of tungsten, but I am not too familiar with the crystal structure. You should be able to look it up by searching beta crystal structure of tungsten, etc.. In any case, I went over all that on a previous post.

 

The quartz crystal structure you already had. Form memory, the image you had linked was the alpha form.

 

 

Now from what you said tungsten is made from the same atom not a combination of many so it is a element, the other materials are made from a combination of different atoms so this means they are compounds?

 

Yes.

 

how would I draw the atoms for the compounds, for example for silicon carbie(SiC) would I get a silicon atom and carbon atom and draw them with a covelant bond?

 

Have a look how it is drawn on wikipedia or have a look at how I drew the polyethylene a few posts back. If you were to draw it, you would simply draw a line between the Si and the C. Bear in mind that you can't isolate a single SiC molecule. The crystal structure is a continuous network of SiC units, all bound to one another.

 

would the bonds for the materials be different because I did some research and found that there are different bonds, covalent, ionic and metalic bonds from what I read the covalant is where the outer shell electrons are shared, the ionic is when one atom gives another its electron making one positivly charged and one negatively and they attratact and the metalic is where the electrons are free and the posotivly charged atoms all atract to the pool of electrons, is this correct or have I been reading wrong?

 

sorry for asking so many questions, hope it does not bother you, thank you for your help

 

Yeah, that's the crux of it. Ionic bonds occur between a metal and a non-metal. Si and C are both non-metals, so do not form ionic bonds but rather covalent bonds.

[ben1793]

Thank you for the help

 

The quartz crystals:

Alpha: http://cst-www.nrl.navy.mil/lattice/struk.picts/sio2a.s.png

Is the alpha a Face Centered Cubic structure? EDIT: Done some more research, is this a Dimond Cubic Structure?

or a trigonal crystal?

Beta: http://cst-www.nrl.navy.mil/lattice/struk.picts/sio2b.png

Is this the correct structure for Beta-Quartz? Also, what type of structure is this (FCC,BCC,SC)? I have been trying to compare with the chart I have but I cant find a resembalance. EDIT: DID SOME MORE SESEARCH AND FOUND THE BETA I HAVE SHOWN IS INCORECT, IT IS SUPPOSED TO BE HEXAGONAL, IS THIS CORRECT?

 

What I read was that alpha beta and delta are crystal structures at different tempratures, will the tempreure range be the same for all the materials or for something like tungsten would the tempreture be different compared to beta-quartz?

 

 

 

For the Silicon Carbide is it possible to create a covalant bond with the atoms conected as images rather than text? I mean the images I had seen had two atoms conected by there electrons in the outer shell, would this be possible to do rather that the polyethelene example you had give because I need to draw them with the atoms and nucleus, I will give an example of the method you explained also but I am not sure if it is possible or not to do it directly with the atom diagram.

 

Also, like you said the silicon carbide crystal structure has about 250 different crystal structures, I did some research and found the 2 most common ones, the alpha and the beta structures.

alpha: Hexagonal

Beta: Cubic

Alpha is formed at temperatures above 1700 C and the beta is under 1700 C

 

Is this correct?

 

Thank you so much for your help.

Edited February 14, 2012 by ben1793

[ben1793]

This is an example of what I meant about drawing the covalent bonds:

 

[hypervalent_iodine]

Thank you for the help

 

The quartz crystals:

Alpha: http://cst-www.nrl.navy.mil/lattice/struk.picts/sio2a.s.png

Is the alpha a Face Centered Cubic structure? EDIT: Done some more research, is this a Dimond Cubic Structure?

or a trigonal crystal?

Beta: http://cst-www.nrl.navy.mil/lattice/struk.picts/sio2b.png

Is this the correct structure for Beta-Quartz? Also, what type of structure is this (FCC,BCC,SC)? I have been trying to compare with the chart I have but I cant find a resembalance. EDIT: DID SOME MORE SESEARCH AND FOUND THE BETA I HAVE SHOWN IS INCORECT, IT IS SUPPOSED TO BE HEXAGONAL, IS THIS CORRECT?

 

Alpha is trigonal, beta is hexagonal.

 

What I read was that alpha beta and delta are crystal structures at different tempratures, will the tempreure range be the same for all the materials or for something like tungsten would the tempreture be different compared to beta-quartz?

 

I don't really know, sorry. In truth, I'm an organic chemist, so this is a little out of my depth.

 

 

For the Silicon Carbide is it possible to create a covalant bond with the atoms conected as images rather than text? I mean the images I had seen had two atoms conected by there electrons in the outer shell, would this be possible to do rather that the polyethelene example you had give because I need to draw them with the atoms and nucleus, I will give an example of the method you explained also but I am not sure if it is possible or not to do it directly with the atom diagram.

 

If you want them the same as in your last post, then yes, but it would be difficult and convoluted.

 

Also, like you said the silicon carbide crystal structure has about 250 different crystal structures, I did some research and found the 2 most common ones, the alpha and the beta structures.

alpha: Hexagonal

Beta: Cubic

Alpha is formed at temperatures above 1700 C and the beta is under 1700 C

 

Is this correct?

 

Thank you so much for your help.

 

Alpha is correct. The beta one is cubic; more specifically, it has a crystal crystal structure similar to diamond, called zincblende.

 

This is an example of what I meant about drawing the covalent bonds:

 

 

 

You could draw them like that, but I would only do it if you absolutely had to.

[ben1793]

THANK YOU THANK YOU THANK YOU, YOU ARE A GENIUS!

 

I was wondering about the covalent bonds, from looking at what you said and doing some more research I found that all atoms want to become NOBEL so does this mean when I am doing silicon carbide I will have to add more than one carbon atom to the silicon to make 8 electrons on the outer shell of the silicon atom or do I only have to add one atom to the silicon for the example?

 

Also the quartz crystal, I tried the link you gave me to find the atomic structure image (the one with the nucleus and electrons) but I could not find any, do you know any websites I could try or do you know anywhere where I could find one, I think the dificulty may be because it is a compound (I think) and that means I will be needing to do the same thing I am doing with silicon (find all the atoms and create a covalent bond).

 

Also, fibre glass, I have come to a conclusion after doing a great deal of research that this is also amorphous (without shape) so I will not find any crystal structure for this, is this correct? I have also realised that this is a compound and in your last post you said this consists of many materials, is there a way I could draw just fibre glass in a atomic structure with a combination of atoms combined with covalent bonding?

 

AGAIN...just want to say thank you, I have a week off and can not contact my teachers for help, you have been so much help

Edited February 17, 2012 by ben1793

[hypervalent_iodine]

I was wondering about the covalent bonds, from looking at what you said and doing some more research I found that all atoms want to become NOBEL so does this mean when I am doing silicon carbide I will have to add more than one carbon atom to the silicon to make 8 electrons on the outer shell of the silicon atom or do I only have to add one atom to the silicon for the example?

 

What you are referring to is called the octet rule. And yes, that is exactly what it means. If you look at the crystal structure you had of it, you'll see all of the SiC molecules are all joined together; each C is bound to 4 Si atoms and each Si atom is bound to 4 C atoms.

 

Also the quartz crystal, I tried the link you gave me to find the atomic structure image (the one with the nucleus and electrons) but I could not find any, do you know any websites I could try or do you know anywhere where I could find one, I think the dificulty may be because it is a compound (I think) and that means I will be needing to do the same thing I am doing with silicon (find all the atoms and create a covalent bond).

 

Wikipedia has some good images. I think I linked it a few posts back, but if not, you can find them here.

 

Also, fibre glass, I have come to a conclusion after doing a great deal of research that this is also amorphous (without shape) so I will not find any crystal structure for this, is this correct? I have also realised that this is a compound and in your last post you said this consists of many materials, is there a way I could draw just fibre glass in a atomic structure with a combination of atoms combined with covalent bonding?

 

Yeah, most likely. As I said on the last page somewhere, you can make fibreglass from a number of different polymers - either a thermoplastic or a thermosetting plastic (eg. epoxys, polyesters or polyvinyl esters). It is usually a combination of a couple of different polymers, so my recommendation would be to find an example of just one polymer and draw that.

 

AGAIN...just want to say thank you, I have a week off and can not contact my teachers for help, you have been so much help

 

That's alright, I enjoy helping where I can. I'm sorry I haven't been more attentive, I've been quite sick the past four or so days and haven't been very active.

Edited February 18, 2012 by hypervalent_iodine

[ben1793]

That's alright, I enjoy helping where I can. I'm sorry I haven't been more attentive, I've been quite sick the past four or so days and haven't been very active.

 

Thank you for your help, dont worry about it your health is much more important than my questions

Hope you get better soon

Edited February 18, 2012 by ben1793

[hypervalent_iodine]

Oh, feel free to keep asking more. I'm bored as anything stuck here in bed.

[mississippichem]

Oh, feel free to keep asking more. I'm bored as anything stuck here in bed.

 

What is the square root of 17? Preferably to at least 26 decimal places.

[hypervalent_iodine]

Geez, off-topic much?

 

Wolfram to the rescue! The square root of 17 to 26 decimal places: 4.12310562561766054982140986

[ben1793]

haha, never knew about wolfram till you told me, its AMAZING.

 

So you said for quartz crystal the atomic structure is SiO₄ in an earlier post, so does this mean 1 silicon atom and 4 oxygens? So I am able to draw this just like I did for SiC by doing 1 silicon atom combined with 4 oxygens?

[hypervalent_iodine]

Have a look at the crystal structure. It just occurred to me that you might not have realised this, but the crystal structures show ball-and-stick models of your compound. Each ball represents an atom and each stick is a bond. They are usually colour coded; carbon is usually grey, oxygen is red, nitrogen blue, etc. In the quartz crystal structures shown on the wiki page, the Si atoms are represented in grey and the oxygen in red.

[ben1793]

Have a look at the crystal structure. It just occurred to me that you might not have realised this, but the crystal structures show ball-and-stick models of your compound. Each ball represents an atom and each stick is a bond. They are usually colour coded; carbon is usually grey, oxygen is red, nitrogen blue, etc. In the quartz crystal structures shown on the wiki page, the Si atoms are represented in grey and the oxygen in red.

 

Ahhh, thank you, never realised that

I will use the link you sent me for the images of the alpha, beta crystal stuctures.

After looking at what you said about the crystal structure being related to atomic structure, would this mean just like crystal structures change at different tempratures the atomic structure would also change?

I am also wondering, how would the sturcture effect the strength of the material for example I mean like the alpha and beta crystal structures for quartz, how would the different structures effect the strength and other properties of the material?

[hypervalent_iodine]

Ahhh, thank you, never realised that

I will use the link you sent me for the images of the alpha, beta crystal stuctures.

After looking at what you said about the crystal structure being related to atomic structure, would this mean just like crystal structures change at different tempratures the atomic structure would also change?

 

The atomic structure would not change, it would still be SiO₄, but the way they arrange them selves (i.e. the crystal structure) might.

 

I am also wondering, how would the sturcture effect the strength of the material for example I mean like the alpha and beta crystal structures for quartz, how would the different structures effect the strength and other properties of the material?

 

It can change it quite a lot. The best example of this is carbon. In one arrangement you get graphite, which consists of layers of carbon sheets and which is flakey and easy to break. In another arrangement, you get diamond. As for the quartz, I don't really know. I would say not very much. The only difference between the two is that one part of the crystal structure is twisted; they way they are linked is exactly the same. In diamond vs. graphite, they way they are linked/bonded together is very different, giving rise to the huge differences in their physical properties.

[ben1793]

I just had a look at the diamond and graphite structures and it amazes me that they both are made of carbon atoms and just because the structure is different one is the hardest material known to man and the other is the weak material used in pencils...WOW

 

Thank you for the help

 

So would it be possible to draw polyethylene as an atomic structure:

I mean I could draw two carbon atoms with four hydrogen atoms but how would I draw the ( )n

[hypervalent_iodine]

Yes, but be aware that the structure actually looks like this:

 

 

Image drawn myself.

 

 

Drawing conventions in organic chemistry are designed so we don't have to spend our lives writing out the letters C and H over and over again (also to reduce clutter). You'll often see images that are literally just a bunch of zig-zag lines. They might not look like much, but believe it or not, these do actually hold quite a lot of chemical information in them. In you above image, the ends of the lines coming out of the parentheses represent CH₃ groups.

[ben1793]

I was looking at the trigonal structure for the quartz crystal, do you know of any advantages or disadvantages of the structure?

 

Also you said the atomic structure never changes only the crystal structure will change, would this be the same for fibre glass? Is there no way to get pure fibre glass without any added atoms? What would be the most common structure for fibre glass?

 

Thank you

 

 

[hypervalent_iodine]

I was looking at the trigonal structure for the quartz crystal, do you know of any advantages or disadvantages of the structure?

 

This is where it starts to get to the limit of my knowledge. I don't know of any advantages, per say. They are chiral, which means that their mirror images are non-superimposable onto on another the same way that your hands are (i.e. your hands are mirror images of each other and if you try to place one hand on top of the other, it won't be superimposable). This means that they can rotate the plane of polarised light to some degree and are in that sense, optically active. That's my best guess, though it doesn't answer your question very well.

 

Also you said the atomic structure never changes only the crystal structure will change, would this be the same for fibre glass? Is there no way to get pure fibre glass without any added atoms? What would be the most common structure for fibre glass?

 

Thank you

 

 

 

Nope. Fibre glass consists polymer reinforced glass fibres; usually they use co-polymers like the epoxy one I linked you.

[ben1793]

 

I went on the epoxy link and found this, how would I draw it, what are the hexagons, what is the OH, does the O stand for oxygen or somethin else?

Is there any crystal structures for the fibre glass epoxy?

 

Also, would you not know of any advantages for the trigonal strucure such as the structure would make the material brittle, like you said in the past graphite is a layered crystal structure so it is very brittle and breaks easy.

Edited February 19, 2012 by ben1793

[hypervalent_iodine]

 

I went on the epoxy link and found this, how would I draw it, what are the hexagons, what is the OH, does the O stand for oxygen or somethin else?

Is there any crystal structures for the fibre glass epoxy?

 

Each point is a carbon with a certain number of hydrogens attached to them (each carbon will have four bonds, so you should be able to work out how many hydrogens are attached to each carbon). The hexagons with the double bonds are called phenyl rings and yes, the O is for oxygen. The OH group is called a hydroxyl group (a hydrogen bound to an oxygen). How to read the above structure properly is a lot for me to write up. Lucky for us, other people have already taken the liberty to writing it. Have a read of this website.

 

Also, would you not know of any advantages for the trigonal strucure such as the structure would make the material brittle, like you said in the past graphite is a layered crystal structure so it is very brittle and breaks easy.

 

I'm sorry, I don't really know. As I said, I'm an organic chemist and this is all very much outside of my area. I suppose a prudent question would be, compared to what?

[ben1793]

Thank you for your help.

 

Does the Epoxy Fibre glass have any crystal structures or is it amorphous?

 

Also what is a commonly used polymer for shape memory polymers that would be suitable for my research?

Edited February 20, 2012 by ben1793

[hypervalent_iodine]

Thank you for your help.

 

Does the Epoxy Fibre glass have any crystal structures or is it amorphous?

 

You won't find a crystal structure for it.

 

 

Also what is a commonly used polymer for shape memory polymers that would be suitable for my research?

 

I already gave you a list. Please read back on the thread.

[hypervalent_iodine]

I have read the wikipedia you sent me on shape memory polymers and found this:

http://upload.wikime..._norbornene.jpg

 

From what I read that is polynorbornene, and it says it is amorphous, this means like you said in the past it has no constant crystal structure but what I was wondering is would this have no structure at all because I mean is it not possible to take the structure at certian points like at when the material is at its ordionary form, also would using the example on the left hand side be ok for a atomic structure image for shape memory polymer?

 

Thank you.

 

Definitely amorphous. If it were crystalline, the material would be a lot more brittle and rigid, which is probably not so good for something marketed as foam. The picture you linked there looks a little odd and might be a bit confusing for you. You'll notice that there are diagonal lines that cut through the structure in between each monomer unit (i.e. between each repeat of the basic chemical unit). If you have a look at the first image, it cuts between two monomer units and each of them is slightly different - the double bond geometry has changed circled in my picture below).

 

 

What this means is that the polymer consists of repeating units of either the first or second type and they occur at random intervals throughout the polymer structure. To illustrate this better, if we say the first type of unit is called A and the second one is B, the polymer might look like this:

 

 

 

 

You can draw it how they have in the image if you'd like (avoid the second one, those silsesquioxane things are a pain to draw) or you could simply draw this:

 

Edited February 22, 2012 by hypervalent_iodine