Talk:Tetragonal crystal system

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Renaming[edit]

I would like to rename this and other articles so that all of the articles describing the seven crystal systems are named the same way. For example, I would like to rename this article Tetragonal crystal system. That way it woun't be confued with the general gemetric shape. Any objections? O. Prytz 17:40, 5 June 2006 (UTC)[reply]

See my response at Talk:Orthorhombic, ditto for here. Vsmith 00:02, 6 June 2006 (UTC)[reply]

Hermann-Mauguin notation[edit]

Truelight: you've made som changes to this and other articles on crystal systems, changing the Hermann-Mauguin notation for some point groups. The original notation wasn't wrong, it was the complete notation, while you have replaced it with the abbreviated notation. We need to find out if this is what we want. The abbreviated form is more commonly used, so that speaks in favour of your changes, but the complete notation should be given somewhere and the relationship between the two should be explained. O. Prytz 14:42, 10 June 2006 (UTC)[reply]

Face centered tetragonal[edit]

I am confused about the lack of face-centered tetragonal on this page.

I have found books that state that indium has a "face-centered tetragonal" crystal structure. However, this article does not show a structure for it, nor does it explicitly state that it exists. The article contradicts itself by stating that tetragonals follow a "centered" crystal structure, from being stretched versions of the body or face-centered crystal structures.

The texts that state this are: 1. "Chemistry of the Elements" by N.N. Greenwood and A. Earnshaw, Pergamon Press 1st Edition 1984 pg. 252. 2. "Physical Metallurgy for Engineers" by Tisza M. ASM International Freund Publishing. pg. 53. (This was from googlebooks so citation information is somewhat truncated, but should still be ample.)

Also, a google scholar search discovered this published paper which states this: 1. Takemura, K., Effect of pressure on the lattice distortion of indium to 56 GPa. Phys. Rev. B 44, 545 - 549 (1991)

I am confused about the lack of face-centered tetragonal on this page.

I have found books that state that indium has a "face-centered tetragonal" crystal structure. However, this article does not show a structure for it, nor does it explicitly state that it exists. The article contradicts itself by stating that tetragonals follow a "centered" crystal structure, from being stretched versions of the body or face-centered crystal structures.

The texts that state this are: 1. "Chemistry of the Elements" by N.N. Greenwood and A. Earnshaw, Pergamon Press 1st Edition 1984 pg. 252. 2. "Physical Metallurgy for Engineers" by Tisza M. ASM International Freund Publishing. pg. 53. (This was from googlebooks so citation information is somewhat truncated, but should still be ample.)

Also, a google scholar search discovered this published paper which states this: 1. Takemura, K., Effect of pressure on the lattice distortion of indium to 56 GPa. Phys. Rev. B 44, 545 - 549 (1991)

Bradridder (talk) 05:26, 30 January 2009 (UTC)[reply]

Hi Bradridder. The reason for this omission is that face-centered tetragonal is the same as body-centered tetragonal. To see this, imagine placing the crystal upright. Then rotate the crystal by 45 degrees around the vertical axis. Then the face-centered atoms in the vertical faces form a tetragonal crystal with edge = a/sqrt(2). The original tetragonal structure atoms are body centered on this new structure, as are the horizontal face-centered atoms. This is considered more fundamental because it's smaller. The same trick doesn't work for orthorhombic because you lose the right angle information. But this point may be worth mentioning in the article. Grj23 (talk) 03:43, 28 October 2009 (UTC)[reply]

History of the name[edit]

I was wondering why it's called tetragonal? In fact all the names of the crystal systems seem a bit odd to me. Does anyone know, and is it worth including either here or in the main article? Grj23 (talk) 03:30, 28 October 2009 (UTC)[reply]

Tetragon means quadralateral in Greek, and "rectangonal" doesn't work because rectangle, from rectangulum, is Latin so you can't pair it with the Greek suffix -gonal. Ginger Conspiracy (talk) 12:02, 11 August 2010 (UTC)[reply]

Impurities[edit]

When this lattice is perturbed by irregularities caused by impurities, is there any way to quantify when it breaks down? E.g., what percentage N% of atoms could be replaced by different atoms with the same bonding characteristics but a M% larger or smaller radius before the coherent lattice would fail to emerge, where N is a function of M (and the ratio extended from cubic cells, if necessary)? Or is that sort of thing only measurable empirically? Ginger Conspiracy (talk) 11:54, 11 August 2010 (UTC)[reply]