Talk:Cubic crystal system

message: I've made some large changes to this article. Most important is that there seemed to be some confusion as to the difference between a cubic lattice and a cubic crystal. This article should be about the cubic lattice with the somewhat confusing name cubic crystal system. For example, the figures show lattice points not atoms, and the pure metal examples mentioned are crystals with a one-atom basis centered on each lattice point. I've also introduced a new table giving the cubic point and space groups. O. Prytz 17:26, 5 June 2006 (UTC)
thread_title: Large changes

message: I've begun to change the article.  I'll write it on the level of a college freshman level texbook.  I'll try to keep it as straightforward as possible.  It's better to convey less information understandably than talk like a professor and have no one understand you.  If they want complete information, they can go to the nearest college's library.
:You assume they live near enough to a college with books in English.  Not that I dissagree with keeping the article straightfoward but I see nothing wrong with linking to more in-depth articles. JIMp talk·cont 13:43, 7 July 2009 (UTC)
thread_title: Beginning to Change

message: The pictures of the FCC and BCC both contain som diagonal lines? That ins't right, is it? At least not if the lines are interpreted as covalent bonds...
:The diagonals clarify the positions of the lattice points, regardless of covalent bonds.--Patrick 12:42, 13 January 2006 (UTC)
thread_title: Covalent Bonds?

message: This writing style of this article belongs in a scientific journal, not an encyclopedia. Having taken two semesters of chemistry - and thus having at least a vague idea of lattice structures - was no help to me in trying to decipher this technically-written article. Perhaps a summary or clarification of the article would help us less educated folk understand it. Thanks
I agree ;).
I agree too. :)
Not bad, but could do with some more information on the various crystal structures eg. volumes of the interstitial sites in each lattice, examples of materials with each lattice (eg. fcc copper, bcc iron), a reference to the hexagonal packing system from fcc (which is not really intuitive!) ..and perhaps some explanation/avoidance of more "technical" terms eg."Galenal type" - not everybody needs passing references to complicated concepts. Could be good - you obviously know your stuff!
--
I'm terrible at writing stuff in wiki format, so here's some info that was being asked about above (figured I'd post it after just having to rederive this stuff for a solution set I'm making).
FCC: 8 tetrahedral sites. Size: 0.414r_a
FCC: 4 octahedral sites. Size: 0.225r_a
BCC: 12 tetrahedral sites. Size: 0.291r_a
BCC: 6 octahedral sites. Size: 0.154r_a
Where r_a is the radius of the "A" atom on the actual lattice sites of the crystal.  — Preceding unsigned comment added by 131.215.30.166 (talk) 21:44, 30 November 2011 (UTC)
thread_title:  Writing Style/Level 

message: Article says that cuprite belongs into gyroidal class but webmineral.com puts it into hexoctahedral class. Siim 18:48, 5 February 2006 (UTC)
thread_title:  Gyroidal class 

message: I read in a paper that J Chem Phys 14:569 proves that Po crystallizes in a simple cubic form, but I'm too lazy to check it out at the library.  Anybody wanna help out and look it up?
:Not right now.  Maybe later.  Is that J. Chem. Phys. A, B, or C? Crystal whacker (talk) 03:00, 20 November 2008 (UTC)
replies: text: I put the direct web link into the article. In 1946, there was just one J. Chem Phys. (Ah, simpler times.) --Steve (talk) 07:12, 20 November 2008 (UTC)
thread_title:  Polonium as simple cubic reference? 

message: I've found Tetartoidal when translating this article to my catalan language and bein in a "cubic" environement I've thought by a common sense deduction it should be Tetratoidal, but maybe I have opened a pandora box
Here are the google books results
*Tetartoidal
*Tetratoidal
Cheers--Mcapdevila (talk) 05:40, 16 July 2011 (UTC)
replies: text: Tetartoidal is correct, see tetartoidal class on Webmineral. Vsmith (talk) 16:06, 16 July 2011 (UTC)
replies: text: There are 8 google book results for tetratoidal (only 4 of which are in English). There are hundreds of results for tetartoidal. Therefore I think we have to assume that 4 people misspelled the word in their books, and tetartoidal is correct. :-) --Steve (talk) 22:23, 16 July 2011 (UTC)

text: The term comes from Ancient Greek τέταρτος (tetartos), meaning "fourth" (as an ordinal) or "quarter" (one fourth), + the suffix -oid(al).  --Lambiam 01:16, 21 October 2012 (UTC)
thread_title: Tetartoidal vs. Tetratoidal

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thread_title:  External links modified 

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thread_title:  External links modified 

message: I believe this is a fundamental misunderstanding of the differences between a crystal system and a lattice. The lattice is the array of infinitesimal points in space. The crystal system is the way in which the motif(s) decorate this lattice. The rocksalt structure is not two interpenetrating face-centred cubic lattices. There is one lattice with two interpenetrating nets of face centred cubic systems of Na+ and Cl- 
This misunderstanding is laid out in Appx. 12 of Burns and Glazer if anyone wants to look at it.
Sgssmlpl (talk) 02:53, 6 May 2019 (UTC)
thread_title:  Description of rocksalt structure as interpenetrating lattices 

message: ===Alternative A: Explain more===
The section  begins with the following:
The isometric crystal system class names, point groups (in Schönflies notation, Hermann–Mauguin notation, orbifold, and Coxeter notation), type, examples, International Tables for Crystallography space group number,[2] and space groups are listed in the table below.
Before this complex sentence, I think it would be good to
#state that each crystal class has a name, identical to that of its (crystallographic) point group;
#state that there are several "Notation systems for crystal classes"; 
#state that crystal class notation systems include Schönflies notation, Hermann–Mauguin notation, orbifold notation, Coxeter notation and that of Conway;
#give the appropriate wikilinks for each notation system, just once, here;
#remove duplicate wikilinks to these notation systems from later in the article;
#state (if known!) the fields that commonly use each notation system.
This information would give a better introduction to the welter of information in the table.  Perhaps it should be a separate, introductory section "Notation systems for crystal classes".  Or maybe an article of its own, which could be linked here in the intro to the table.  In this direction, note that
#the (start-class) article crystallographic point group contains a basic discussion of three notation systems, their correspondences and their users, but little else;
#the (C-class) article crystal system also invokes the different notation systems, without describing or comparing them;
#and even the (B-class) article crystal structure uses the different notation systems, without describing or comparing them. 
Perhaps the first of these three, (crystallographic point group), is the best place to offer a fuller description and discussion of the various notation systems?
===Alternative B: Say less===
An alternative:  reduce the amount of information in this table, making it simpler to understand.  For a first reading, nobody will need all the information given in this section.  We could, for example, entirely remove any reference to the orbifold or Coxeter notations.  (Though somebody would protest, most likely.)
===Class number is unclear===
Note that the "International Tables for Crystallography" space group numbers given in the first column of the table each corresponds to exactly one of the space group codes ("names") given in the last three columns; however the table doesn't make clear which one.  Consider combining the number and its corresponding code in the last three columns e.g. "195: P23" in the first cell of column "Primitive".  yoyo (talk) 05:20, 27 August 2019 (UTC)
replies: text: Yes, this section is completely unclear. The relationship to cubic crystal systems is not given. Geoffrey.landis (talk) 22:12, 11 February 2022 (UTC)
thread_title:  Notation systems for crystal classes 

message: Note that the "International Tables for Crystallography" space group numbers given in the first column of the table each corresponds to exactly one of the space group codes ("names") given in the last three columns; however the table doesn't make clear which one.  Consider combining the number and its corresponding code in the last three columns e.g. "195: P23" in the first cell of column "Primitive".  yoyo (talk) 05:20, 27 August 2019 (UTC)
replies: text: Yes, this section is completely unclear. The relationship to cubic crystal systems is not given. Geoffrey.landis (talk) 22:12, 11 February 2022 (UTC)
thread_title: Class number is unclear

message: The phrase
 These tetrahedral voids are not local maxima and are not technically voids, but they do occasionally appear in multi-atom unit cells.
is unclear because it is not stated what should be maximum in them nor what the word technically exactly means. This statement for the bcc holds for the following fcc? Does "appear" mean "contain atoms"?
It is possible to give the relative radii of the octahedral and tetrahedral holes? This is interesting because the article steel says that the fcc structure is "more open" than the bcc, in spite of its higher packing factor (this is why I arrived here).
pietro151.29.1.146 (talk) 13:01, 24 January 2020 (UTC)
thread_title:  unclear