2D networks

 Synchrotron
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2D networks
Hi,
is anyone familiar with the Wells notation of networks? The attached scan is from the textbook 'Structural Inorganic Chemistry'.
I know that in the middle in the AX case is the usual (4,4) square grid type. But what is the notation of the AX2 one at the right hand?
is anyone familiar with the Wells notation of networks? The attached scan is from the textbook 'Structural Inorganic Chemistry'.
I know that in the middle in the AX case is the usual (4,4) square grid type. But what is the notation of the AX2 one at the right hand?
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 Synchrotron
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Re: 2D networks
Hi Rudi
Do you mean how to convert the in to an alternative notation?
Do you mean how to convert the in to an alternative notation?

 Synchrotron
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 Joined: 12 Dec 2008, 15:56
 Location: Saxony
Re: 2D networks
Hi John,
I mean the Wells notation of nets, something like (4,4) as depicted in the middle. Or SiO2 has a (4,2) net for example. There should be also a Wells notation for the net depicted at the right hand?
I mean the Wells notation of nets, something like (4,4) as depicted in the middle. Or SiO2 has a (4,2) net for example. There should be also a Wells notation for the net depicted at the right hand?

 Synchrotron
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 Joined: 13 May 2006, 14:25
 Location: UK
Re: 2D networks
Cheers Rudi
I'd missed the words Wells I think I need some new glasses.
I'd missed the words Wells I think I need some new glasses.

 Olex2 Boffin
 Posts: 694
 Joined: 24 Nov 2008, 21:34
Re: 2D networks
Hi Rudi,
the Wells notation for the net on the right is the same  (4,4) or 4^{4} or 4^{4}6^{2} (??????). The spacers are normally excluded from the notation,
Cheers,
o
the Wells notation for the net on the right is the same  (4,4) or 4^{4} or 4^{4}6^{2} (??????). The spacers are normally excluded from the notation,
Cheers,
o
Last edited by johnewarren on 15 Jan 2010, 16:33, edited 2 times in total.
Reason: Tex with <sup> = superscript added. Forum now supports native sup/sub with correct braces  changed <> braces []
Reason: Tex with <sup> = superscript added. Forum now supports native sup/sub with correct braces  changed <> braces []

 Synchrotron
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 Joined: 12 Dec 2008, 15:56
 Location: Saxony
Re: 2D networks
Really?oleg wrote: the Wells notation for the net on the right is the same  (4,4)
I guess this is Schläfli notation, isn't it?or 4<sup>4</sup> or 4<sup>4</sup>6<sup>2</sup>.
And in the case of a (4,2) net in SiO2? Does the 2 not describe the oxygen spacers between the tetrahedral silicium?The spacers are normally excluded from the notation,

 Olex2 Boffin
 Posts: 694
 Joined: 24 Nov 2008, 21:34
Re: 2D networks
Hmm, I though that quartz has 6<sup>4</sup>8<sup>2</sup> network (it is the Schläfli notation indeed).
Considering the symbol you provided  (4,2), I would think of 1D array, though in this case without the connectivity it would make either a 'ladder' of rectangles sharing edges for three connected node or a chain of rectangles sharing vertexes for 4connected node...
May be I am confusing something regarding inorganic and organometallic frameworks... But if 2connected atoms (nodes) were included into the topological symbols for organometallic frameworks they would become useless (because they would describe chemical connectivity, preventing comparing and classifying the topologies) and unmanageable.
But in the case you really wanted to include the 2connected entities into the network description, the symbol would be
(8,2)<sub>2</sub>(8,4)  for the 2 and 4 connected nodes respectively
Considering the symbol you provided  (4,2), I would think of 1D array, though in this case without the connectivity it would make either a 'ladder' of rectangles sharing edges for three connected node or a chain of rectangles sharing vertexes for 4connected node...
May be I am confusing something regarding inorganic and organometallic frameworks... But if 2connected atoms (nodes) were included into the topological symbols for organometallic frameworks they would become useless (because they would describe chemical connectivity, preventing comparing and classifying the topologies) and unmanageable.
But in the case you really wanted to include the 2connected entities into the network description, the symbol would be
(8,2)<sub>2</sub>(8,4)  for the 2 and 4 connected nodes respectively

 Synchrotron
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 Joined: 12 Dec 2008, 15:56
 Location: Saxony
Re: 2D networks
For certain reasons I'm dealing with terminology of networks again. So, I would like to bring this thread into the focus.
In the attached figure (taken from Steed/Atwood  Supramolecular Chemistry), the corresponding Wells notation of the plane net with the SchläfliSymbol (4.8^{2}) is (4,8^{2}), according to the figure caption. This is not clear to me.
In the (n,p) notation of Wells, n is the size of the smallest circuit (i. e. number of nodes in the shortest path) and p is the connectivity of the nodes.
For the mentioned net, the nodes are certainly not 8connected but rather 3connected. The size of the smallest circuit should be 4. Is it a mistake in the figure caption?
Yes, you're right, Oleg. Twoconnected points are not included, since they do not alter the basic system. Therefore, a Wells notation (4,2) should not exist. My fault.oleg wrote:Hmm, I though that quartz has 6<sup>4</sup>8<sup>2</sup> network (it is the Schläfli notation indeed).
Considering the symbol you provided  (4,2), I would think of 1D array, though in this case without the connectivity it would make either a 'ladder' of rectangles sharing edges for three connected node or a chain of rectangles sharing vertexes for 4connected node...
In the attached figure (taken from Steed/Atwood  Supramolecular Chemistry), the corresponding Wells notation of the plane net with the SchläfliSymbol (4.8^{2}) is (4,8^{2}), according to the figure caption. This is not clear to me.
In the (n,p) notation of Wells, n is the size of the smallest circuit (i. e. number of nodes in the shortest path) and p is the connectivity of the nodes.
For the mentioned net, the nodes are certainly not 8connected but rather 3connected. The size of the smallest circuit should be 4. Is it a mistake in the figure caption?
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 Olex2 Boffin
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Re: 2D networks
Hi Rudi,
yes it must be a typo... or misunderstanding , please refer to this recent paper to find out why :
CrystEngComm, 2010, 12, 44  48
This paper explains the difference between different notations and names/symbols and their missuses.
So for nonuniform nets the point symbols should be used (as by Wells) and that would be 4.8^{2} (page 46 of that paper),
Cheers,
Oleg
yes it must be a typo... or misunderstanding , please refer to this recent paper to find out why :
CrystEngComm, 2010, 12, 44  48
This paper explains the difference between different notations and names/symbols and their missuses.
So for nonuniform nets the point symbols should be used (as by Wells) and that would be 4.8^{2} (page 46 of that paper),
Cheers,
Oleg

 Synchrotron
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 Joined: 12 Dec 2008, 15:56
 Location: Saxony
Re: 2D networks
Hi Oleg,
I know this recent paper by Blatov et al. but it's rather confusing in my opinion.oleg wrote: yes it must be a typo... or misunderstanding , please refer to this recent paper to find out why :
CrystEngComm, 2010, 12, 44  48
This paper explains the difference between different notations and names/symbols and their missuses.
What is the typo now? Is 4.8^{2} not a Schläfli but a point symbol? What about 6^{3}? Schläfli or point symbol? Blatov et al. stated that point symbol have often been misused as Schläfli symbols.So for nonuniform nets the point symbols should be used (as by Wells) and that would be 4.8^{2} (page 46 of that paper),

 Olex2 Boffin
 Posts: 694
 Joined: 24 Nov 2008, 21:34
Re: 2D networks
According to the paper the (p,q) notations can only be used for the uniform nets and for nonuniform nets a combination of point symbols should be used, so 4.8^{2} is the Wells (point???) symbol for this nonregular net and (4,8^{2}) makes no sense... I do also find the paper a bit confusing but it makes the point  many people call same things differently and different things the same... For example Olex evaluates and prints short and long topological terms, which are as I suspect called point symbols and vertex symbols in this paper...

 Synchrotron
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 Joined: 12 Dec 2008, 15:56
 Location: Saxony
Re: 2D networks
I guess uniform or regular net means that all nodes exhibit the same connectivity (uninodal) and all circuits have the same size. Correct?oleg wrote:According to the paper the (p,q) notations can only be used for the uniform nets and for nonuniform nets a combination of point symbols should be used, so 4.8^{2} is the Wells (point???) symbol for this nonregular net
According to Blatov's paper Schläfli symbols are those in braces, e.g. {p,q} for a 2D net in which q p's meet at each knot. For instances in the common honeycomb pattern, three hexagons meet at each knot and the Schläfli symbol is hence {6,3}. However, I always thought that Schläfli symbols are noted with the supscript (e. g. 6^{3}) according to the figure from the textbook. In Blatov's paper those symbols are called point symbols and the symbols in the textbook would be another example for misuse of the term Schläfli symbol? Quite confusing.
Ok, maybe I should drop Jon Steed a short line. If you meet him in the hall, you may ask him, too.and (4,8^{2}) makes no sense...
This phenomenon seems to be quite universal in chemistry but this is another thing.many people call same things differently and different things the same...
Interesting. I was not aware that Olex2 is able to evaluate network topologies.For example Olex evaluates and prints short and long topological terms, which are as I suspect called point symbols and vertex symbols in this paper...

 Olex2 Boffin
 Posts: 694
 Joined: 24 Nov 2008, 21:34
Re: 2D networks
exactlyI guess uniform or regular net means that all nodes exhibit the same connectivity (uninodal) and all circuits have the same size. Correct?
In the stack order... Olex is not Olex2 and is actually developed for that particular case to get those topological terms (I must have been very clever those days not call them anything  but just topological terms ). And if anybody still thinks that Olex is a predecessor to Olex2 (http://en.wikipedia.org/wiki/Olex2), that is wrong... The only seams are the OpenGL and me... Also please take a look at this newsletter: http://iucrcomputing.ccp14.ac.uk/iucrt ... index.html, where I do describe how those various things are calculated or rather enumerated.
Then whatever you call a misuse could be a simple misunderstanding... And most things are really confusing
Last edited by oleg on 18 Jan 2010, 10:31, edited 1 time in total.

 Synchrotron
 Posts: 708
 Joined: 12 Dec 2008, 15:56
 Location: Saxony
Re: 2D networks
Oh, I see. But you have to admit that the name Olex likely implies that it's a predecessor to Olex2. Anyway, is Olex still an active project?oleg wrote: And if anybody still thinks that Olex is a predecessor to Olex2 (http://en.wikipedia.org/wiki/Olex2), that is wrong, wrong aim, wrong audience...
It's not grown on my dung. Blatov et al. speak of misuse in more than 300 RSC and ACS publications.Then whatever you call a misuse could be a simple misunderstanding... And most things are really confusing

 Olex2 Boffin
 Posts: 694
 Joined: 24 Nov 2008, 21:34
Re: 2D networks
No Olex is not being actively developed, however if any bugs are found or assistance is required  I would be glad to help.