[ben1793]

I cant find any images of an atomic structure and molecules or lattice structures for the following:
Tugsten
Polyethelene
Silicon Carbide
Quartz Crystal
Glass Fibre Reinforced Plastic
Shape Memory Polymer

If you have any links to where I could find a suitable image for any of these please tell me.
Thank you.

PS. sorry I am not very good with chemistry I am a mechanical engineering student and am studying materials so thats why I need to know.

Done some research more and found these, can you correct me if I am wrong please, I am not very good at chemistry.

Tungsten
Bohr Diagram: http://www.chemicale.../bohr/b0074.gif
Lattice Structure: http://cst-www.nrl.n....picts/bh.s.png

Polyethylene:
Bohr Diagram: http://www.chelation...mages/b0030.gif not sure about this one
Lattice Structure: http://www.ndt-ed.or...hyleneChain.jpg

Silicon Carbide:
Bohr Diagram: http://mrsljones.wik..._bohr_model.jpg this had many different bohr diagrams so I am not sure about this one to, it says silicon, is silicon carbide different?
Lattice Structure:http://www.iucr.org/__data/assets/image/0018/13239/img43.gif Not to sure about this one either.

Glass fibre reinforced plastic:
Bohr Diagram: cant find anything
Lattice Structue: cant find anything

Quartz Crystal:
Bohr Diagram: cant find anything
Lattice Structure:http://cst-www.nrl.navy.mil/lattice/struk.picts/sio2a.s.png

Shape Memory Polymer:
Bohr Diagram:cant find anything
Lattice Structure:cant find anything

That is all I could find but I am not sure even if the stuf I have found is correct or not, please look at it and tell me.

Thank you.

This post has been edited by ben1793: 3 February 2012 - 05:13 PM

[ben1793]

need to find a tugsten atom (bohr diagram) and a crystal structure (lattice structure)
I cant find any anywhere, I have asked for help but know one knows....I have found these but I dont know if they are correct or incorrect:

Bohr diagram:
http://www.chemicale.../bohr/b0074.gif

Lattice Structure: I have fund 2 different ones I dont know which is correct:
http://cst-www.nrl.n....picts/a2.s.png
Or
http://cst-www.nrl.n....picts/bh.s.png

[ewmon]

ben1793, on 4 February 2012 - 11:38 AM, said:

need to find a tugsten atom (bohr diagram) and a crystal structure (lattice structure) I cant find any anywhere, I have asked for help but know one knows....I have found these but I dont know if they are correct or incorrect:

Bohr diagram:
http://www.chemicale.../bohr/b0074.gif

Information required to determine the accuracy of the given Bohr diagram for tungsten:

• What is a Bohr diagram?
  
• How do you draw one?
  
• What would a tungsten Bohr diagram look like?

So I searched for the definition of the Bohr diagram.

• The first result defines the Bohr diagram.
  
• The second result instructs on drawing one.
  
• You then determine what a tungsten Bohr diagram would look like.

This post has been edited by ewmon: 4 February 2012 - 02:23 PM

[ben1793]

sorry I am not very good with chemistry, might have said the wrong terminology, I have been given the task to find an atomic structure for various materials one of them is tugsten but I cant seem to find it, I need a atomic structure for tugsten and also what I think is called a lattice structure, which I think is a 3d model of how the atoms combine, at first I thought it was called a molecule but I was corrected when I read an article explaning about metal atoms bonding.
My question really is asking if the links I gave above are correct or incorrect, if incorrect could you please show me what it shoule look like?

Thank you.

[hypervalent_iodine]

ben1793, on 3 February 2012 - 05:40 PM, said:

I cant find any images of an atomic structure and molecules or lattice structures for the following:
Tugsten
Polyethelene
Silicon Carbide
Quartz Crystal
Glass Fibre Reinforced Plastic
Shape Memory Polymer

If you have any links to where I could find a suitable image for any of these please tell me.
Thank you.

PS. sorry I am not very good with chemistry I am a mechanical engineering student and am studying materials so thats why I need to know.

Done some research more and found these, can you correct me if I am wrong please, I am not very good at chemistry.

I'm not too sure what you want when you ask for the atomic structure. More importantly, why do you want it for? If you can explain the purpose, I/we can possibly point you in the right direction. Since the majority of what you have listed are organic polymers or inorganic complexes, the Bohr models you are trying to find aren't going to be of any use. Also, you will need to be more specific with the type of glass.

Quote

Tungsten
Bohr Diagram: http://www.chemicale.../bohr/b0074.gif
Lattice Structure: http://cst-www.nrl.n....picts/bh.s.png

The crystal structure of tungsten is a body centred cubic and, IIRC, can have a number of space groups. The question I have for you is, do you want tungsten by itself or a tungsten containing complex, such as the tungsten carbide in the lattice structure picture that you linked?

Quote

Polyethylene:
Bohr Diagram: http://www.chelation...mages/b0030.gif not sure about this one
Lattice Structure: http://www.ndt-ed.or...hyleneChain.jpg

First one is definitely wrong. Even ignoring the fact that the numbers of protons and neutrons (and electrons, really) are all out of whack, these sorts of images are kind of pointless when you start involving compounds beyond 1 atom. This brings me back to the question of why you need such a thing in the first place? The last image isn't a lattice/crystal structure, it is simply the molecular structure. Polyethylene will have varying crystal structures depending on what type of polyethylene it is (high-density, low-density, high-molecular weight, cross-linked, etc., etc.).

Quote

Silicon Carbide:
Bohr Diagram: http://mrsljones.wik..._bohr_model.jpg this had many different bohr diagrams so I am not sure about this one to, it says silicon, is silicon carbide different?
Lattice Structure:http://www.iucr.org/__data/assets/image/0018/13239/img43.gif Not to sure about this one either.

I looked this one up and found that there are over 250 different types of crystal structure for this compound. Do you only need an example of one? The Bohr diagram you have there is only for the silicon atom. Again, I have to ask why you need this?

Quote

Glass fibre reinforced plastic:
Bohr Diagram: cant find anything
Lattice Structue: cant find anything

This is fibre glass, yes? If so, there are a lot of different materials used for fibre glass, so you again need to be more specific.

Quote

Quartz Crystal:
Bohr Diagram: cant find anything
Lattice Structure:http://cst-www.nrl.navy.mil/lattice/struk.picts/sio2a.s.png

Quartz is made up of a continuous SiO₄ lattice. There are actually two different crystal structures for it, one for alpha quartz and one for beta-quartz. The one you have linked is alpha.

Quote

Shape Memory Polymer:
Bohr Diagram:cant find anything
Lattice Structure:cant find anything

That is all I could find but I am not sure even if the stuf I have found is correct or not, please look at it and tell me.

Thank you.

These are a class of polymers, rather than a specific one. Which one are you talking about?

ben1793, on 4 February 2012 - 02:37 PM, said:

sorry I am not very good with chemistry, might have said the wrong terminology, I have been given the task to find an atomic structure for various materials one of them is tugsten but I cant seem to find it, I need a atomic structure for tugsten and also what I think is called a lattice structure, which I think is a 3d model of how the atoms combine, at first I thought it was called a molecule but I was corrected when I read an article explaning about metal atoms bonding.
My question really is asking if the links I gave above are correct or incorrect, if incorrect could you please show me what it shoule look like?

Thank you.

What you seem to be after is simply the molecular structure, which is what you linked as the lattice structure for the polyethylene in your OP, as well as the crystal structure. The molecular structure will show you what one molecule of your compound looks like, what kind of bonds it has and the molecular geometry. The crystal structure will show how a group of these molecules pack together in 3D space. You have linked a number of these types of pictures, the tungsten carbide you linked being one such example. You are going to find it very difficult to gather this information for some of the materials you have listed. Fibre glass, for instance, is a combination of some kind of polymer (thermopolyers and epoxy resins, etc.) with fine glass fibres embedded within the crystal structure - so you have two different compounds, not just one.

[ben1793]

Wow thank you, very descriptive, just what I needed great help thank you.

I have just started materials at college, I am dong one of the assignments and got stuck on this part of it, it wants me to describ the structure including the atomic structure of the materials I had listed above, I was told that I have to draw an image of the atom itself, the atomic structure (he give us an example of a 3D model and did not explain it much). I would ask the teacher but is the weekend and I have completed the rest of the assignment just this last little bit but I am stuck.

Again thank you for the help, saved me a great deal of time because I was going to start drawing the links I listed and describing them, luckily you saved me from doing the wrong thing, thank you

[hypervalent_iodine]

Ah. So it sounds more like they're asking for you to give a molecular formula, coupled with a drawing of its structure. So for instance, your polyethylene would have an empirical formula of CH₃(CH₂CH₂)_nCH₃ and its structure would be drawn like this:



Or like this:



(images from wikipedia)

I don't think they want you to actually draw a diagram of the atoms, including all the electrons, protons, etc. Similarly, I think that drawing the crystal structures might not be what they are asking of you, as it would be a long and tedious thing to have to do, but I would definitely check that if possible. Even still, you might run into some difficulties with the fibre glass and memory polymers, since they incorporate a lot of different polymers, but I'm sure you can work around it.

[ben1793]

They showed the class and example of what we had to do and they showed an atom (drawn) and a 3D atomic structure, the one they showed was like a cube with some atoms inside and another one where there was atoms sitting ontop of eachother like a chain of atoms, they asked us to do it that way, will it be very hard?

This post has been edited by ben1793: 4 February 2012 - 05:48 PM

[hypervalent_iodine]

It will take you some time, but it won't be hard. That's the crystal structure that they've given you an example of.

[ben1793]

Thanks for the help

The thing that is cnfusing me is when I try typing something like tugsten crystal structure on google images I get about 10 different types of structures on the page, I just dont know what one I am supposed to be doing. Do you have any good images for a tugsten crystal structure and atom please?

This post has been edited by ben1793: 4 February 2012 - 11:03 PM

[ben1793]

I am geting the same problem again, just cant find 1 image, allways 10 or more different ones on one page.
Could somebody help me find some images please?

[hypervalent_iodine]

Unfortunately, since this is an assignment it would be wrong of a member here to do that (speaking of which, I am moving this thread to homework). The task is up to you. I understand your confusion, but perhaps you might be best emailing your professor and asking him for some clarification as he would be more aware of the exact requirements for your work.

[ben1793]

Its research for the assignment, I need to get the images and describe them, how the atoms are conected explain about the structure and the structure, I just need to know what it looks like so I can explain it, drawin the atom is for additional information in describing the structure but describing is the main point of the assignment and that I will do myself.

This post has been edited by ben1793: 6 February 2012 - 11:04 AM

[hypervalent_iodine]

Well, the problem is still that a lot of your materials aren't specific to a particular compound, which is really not something we can help with. You will need to ask your professor what he wants - i.e. if any example is fine or if he wants a particular compound.

[ben1793]

Ok, I will ask him next time I see him, thank you for your help, learnt loads of things from you so far thank you
when you say compound what does that mean, do you mean there are different combintaions of elements for tugsten so there are loads of different types of tugsten? I saw something called "W" when I was looking for tugsten is that not just a tugsten atom on its own?

EDIT: did some more research about compinds, by compunds do you mean things like sc, bcc?

This post has been edited by ben1793: 6 February 2012 - 11:36 AM

[hypervalent_iodine]

To put it simply, a chemical compound is defined as a set number of atoms that are joined together by various chemical bonds in a specific arrangement. CO₂ or water (H₂O) are examples of a compound, which you might also refer to as a molecule of carbon dioxide or a molecule of water.

"W" is the symbol for tungsten, as per the periodic table. Tungsten can form a number of different complexes with other atoms, by which I mean it can bond to various atoms and other compounds to form a rather wide array of molecular archetypes. Assuming you're after metallic tungsten, which is an array of just tungsten atoms, you would be looking for something similar to what was linked to you on chemicalforums. The bcc mentioned stands for body-centred cubic, which is a type of crystal structure and describes the way in which the atoms arrange themselves in space. It gives information on the symmetry of what's called the unit cell, which is useful for a number of reasons. You might like to read this wiki article on it.

For polyethylene, the compound involved is a polymer of repeating ethyl units, as I showed in post #7. However, even though the title of this material links you to a specific compound, what it does not do is tell you what type of polyethylene you are dealing with. You can have things like low-density polyethylene (LDPE) or high-density polyethylene (HDPE) (among others), which is important for you since the major distinction between the two is the way in which they are packed together (I made a post on a similar topic once, which can be found here if you're at all interested in reading it). For the purposes of your assignment, I should think that you are after HDPE rather than LDPE. My reasoning is that the latter exhibits a larger degree of branching and is, IIRC, an amorphous or semi-crystalline solid - it packs together in a fashion similar to a bowl of spaghetti as a result of this. In comparison, HDPE has less branching and will therefore pack very tightly together and be as close to linear as a polymer can get, making it much easier for you to draw. Still, this is something worth checking with your professor.

Fibre glass and memory shape polymers, as I mentioned, encompass a number of different compounds. If you are trying to draw these, you aren't going to be able to draw all the different polymers used, because there are simply too many. This is what I meant when I said you need to ask your professor for clarification - does he want a specific polymer, or is any example fine? In the case of the latter, fibre glass contains anything from epoxy resins to thermopolymers, so if you look up something along the lines of "thermopolymer + fibre glass", you should get some sort of list of the thermopolymers used in fibreglass. Similarly for the memory shape polymers, there is a wiki article that gives examples of the types of polymers used - things like polyurethanes, etc.

The remaining materials are all very well defined compounds and you should have too much of an issue finding things on them. Try looking up the names of the compounds themselves in Wolfram alpha. Quite often Wolfram will give you information on the crystal structure, which is what you seem to be in need of.

Hope that helps.

[ben1793]

Thank you, you have helped me allot with all the information you have given me, I did as you said and asked my teacher today....turns out that we still have another lesson before we start the assignment, last lesson he gave us it and told what he basicly wanted but next lesson he was going to explain how we do it, he has given me a handout from the other group he did the lesson with and I am going to read that now, allready had a quick scan over it but going to spend my time and read it now, he has even made a chart showing what crystal structure the material is under, tungsten is under bcc, now the question becomes, why is there only tungsten, I read that some materials change there crystal structure at different tempratures so it is not possible to get a crystal for such materials, is this the case with most the materials listed above? Also, are the atoms I shown above in the links also incorrect?

Just want to say thank you for helping me so far, I am learning loads of new information.

[hypervalent_iodine]

Quote

now the question becomes, why is there only tungsten

I would assume there is only tungsten simply because that is what the question is asking you for. It can form a number of compounds, but your question only asks for tungsten, so you can assume it is asking for the crystal structure of only those atoms. Tungsten does in fact have allotropes (allotropes are different arrangements of the same molecule; diamond and graphite are allotropes of carbon, for instance), termed alpha, beta and gamma. I don't know terribly much about the last two, except that beta tungsten decomposes to alpha tungsten upon heating.

Quote

I read that some materials change there crystal structure at different tempratures so it is not possible to get a crystal for such materials, is this the case with most the materials listed above?

All of the polymers definitely will, depending on how high the temperature is. I'm not so sure about the rest. Depending on the specific polymer, getting crystal structure might not be able to be achieved because they don't form proper crystals. Crystal structures are obtained using X-ray crystallography, which is a wonderful technique that is incredibly useful, but it does of course depend on the ability for the compound to form crystals. Semi-crystalline polymers such as LDPE wouldn't really work in this as it doesn't have the necessary molecular order.

Quote

Also, are the atoms I shown above in the links also incorrect?

You'll have to tell me which ones you are talking about.

Quote

Just want to say thank you for helping me so far, I am learning loads of new information.

Not a problem, that's what SFN is here for

[ben1793]

Thank you, I am talking about these atoms:
Tugsten:
http://www.chemicale.../bohr/b0074.gif

Polyethelene:
I cant find an atomic structure, the one I showed above was wrong and the structre you showed me was written, I am looking for a structure like the others which is a nucleus with proton/neutorns and electrons obrbiting it.

Silicon Carbide:
http://mrsljones.wik..._bohr_model.jpg
I think you had mentioned this is just silicon, just asking again to confirm because I need silicon carbide.
Also I was just searching and found this: http://www.gold-aqua...ilicaimage3.jpg is this a correct crystal structure for silicon carbide (the one on the top right corner) or like the others does it not have one.

Quartz Crystal
Cant find any atomic structure

Glass Fibre Reinforced Plastic I think you are right about this being fibre glass
Cant find any atomic structure

Shape Memory Polymer Is there not one basic atomic structure for a shape memory polymer?
Cant find any atomic structure

If you know of any websites that I could use to find the missing images please could you give me a link.
Thank you

This post has been edited by ben1793: 7 February 2012 - 10:49 AM

[hypervalent_iodine]

ben1793, on 7 February 2012 - 10:44 AM, said:

Thank you, I am talking about these atoms:
Tugsten:
http://www.chemicale.../bohr/b0074.gif

It's correct for one isotope of Tungsten, that being ¹⁸⁴W. Again, though, I'm very skeptical that you need Bohr diagrams.

Quote

Polyethelene:
I cant find an atomic structure, the one I showed above was wrong and the structre you showed me was written, I am looking for a structure like the others which is a nucleus with proton/neutorns and electrons obrbiting it.

Is that really what your assignment is asking you for? You won't find those sorts of images for anything past one atom, as I have already stated. Those types of images don't really make concessions for chemical bonds, so they are useless for what you want. You can get just as much information about the atomic structure (and then some) by drawing them as per the normal chemical convention (as in my example of the polyethylene); all it requires is for you to know how to read the image.

Quote

Silicon Carbide:
http://mrsljones.wik..._bohr_model.jpg
I think you had mentioned this is just silicon, just asking again to confirm because I need silicon carbide.
Also I was just searching and found this: http://www.gold-aqua...ilicaimage3.jpg is this a correct crystal structure for silicon carbide (the one on the top right corner) or like the others does it not have one.

Yes, that image represents only a single atom and that atom is silicon. Silicon carbide is made up of a continual lattice of SiC. The second image you showed is one of many SiC polymorphs.

Quote

Glass Fibre Reinforced Plastic I think you are right about this being fibre glass
Cant find any atomic structure

I know I am

Quote

Quartz Crystal
Cant find any atomic structure

And:

Quote

Shape Memory Polymer Is there not one basic atomic structure for a shape memory polymer?
Cant find any atomic structure

If you know of any websites that I could use to find the missing images please could you give me a link.
Thank you

No, there isn't one basic structure. There are a number of different polymers you can use. Have a look at the wikipedia page I linked a few posts back.

You need to clarify what your professor wants in terms of atomic structure. I do not think it is the images you seem to be searching for.