Talk:Bravais lattice

Deleted redirect

I've removed the redirect and started a new article. This needs a bit of more work, please feel free to edit (although I think the mathematical formalism should be kept to a minimum).O. Prytz 22:16, 9 January 2006 (UTC)

Errors in diagrams

The "sub-captions" within the 2D figure are misleading in their use of the ≠ symbol. In 2 and 3 (rect and centred rect) |a1|≠|a2| indicates |a1| is unequal to |a2|. In 1 (oblique) |a1|≠|a2| instead indicates that there is not necessarily equality. /toen — Preceding unsigned comment added by 50.191.182.83 (talk) 19:12, 6 May 2015 (UTC)

Unfortunately all of the diagrams showing three angles here are wrong. The angle gamma as shown can be calculated from the angle alpha since they are both part of the same quadrilateral, whose angles must sum to 180 degrees. New diagrams with the angles in the correct places are needed. --Chymicus 19:33, 24 July 2006 (UTC)

Another error of note: in the pictures representing the 5 different 2-d lattices the lattice vectors shown for the "centered rectangular" lattice appear to be in error.--adam 02:40ish, May 26, 2008. —Preceding unsigned comment added by 76.121.52.100 (talk) 09:43, 26 May 2008 (UTC)

I can spot diagram error for Monoclinic, its gamma angle that should be different. I am comparing this to Ashcroft-Merbin Solid state physics book, page 118. Spiralciric (talk) 13:12, 15 November 2012 (UTC)

Is anyone planning to DEFINE Bravais lattices???

This article has one of the most deficient definitions among all mathematics articles. There are 14 Bravais lattices in what sense? In other words, what makes two Bravais lattices equivalent? Without this information, the article may as well be chicken scratchings.Daqu 15:52, 28 November 2006 (UTC)

Furthermore, the description of the different kinds of Bravais lattices makes great use of the word cell without once mentioning what cell is being discussed.

Lastly, please note the the expression "a ≠ b ≠ c", used repeatedly in describing various diagrams, does not exclude the possibility a = c.Daqu 16:00, 28 November 2006 (UTC)

I believe that wikipedia articles are by definition "works in progress". If you are knowledgeable in this area, perhaps you can pitch in and do the necessary? --Rifleman 82 16:12, 28 November 2006 (UTC)

Six Bravais types in 2d

The monoclonic lattices have different symmetry groups depending on whether a and b are equal or not: in the former case the symmetry group contains a reflection permuting the two lattice basis vectors, therefore, there are really six types. — Preceding unsigned comment added by 83.236.109.227 (talk) 11:37, 16 April 2024 (UTC)

Monoclinic lattice images

I've replaced images for Monoclinic lattices from Monoclinic.svg to Monoclinic.png / Monoclinic-base-centered.svg to Monoclinic-base-centered.png. Maybe the png version of these are more correct in the description of their angles. -- Anonymous

I'm an idiot. Images have now been corrected, and will go back to the SVG versions. Thanks for pointing this out. Stannered 14:33, 18 March 2007 (UTC)

Actually, all the monoclinic crystal diagrams are incorrect, since they should show beta ≠ 90°, rather than alpha. See talk page for Crystal system. Wolf.aarons (talk) 17:26, 20 April 2010 (UTC)

The Figure of HEXAGONAL

I think the figure shown for hexagonal is incomplete( and even wrong) as there are 3 lattice positions which are not shown. They are actually at the midway joining the centres of triangles formed by the base diagonals. There are only 3 such positions at 120^o to each other. --Swagat konchada 15:56, 2 August 2007 (UTC)

The hexagonal lattice shown is correct. If i understand you correcty, you are thinking of a Hexagonally Close packed lattice is not a bravais lattice (see Glaser, Group theory for Solid State Scientists) 129.78.220.7 01:58, 3 August 2007 (UTC)

HCP is a Bravais lattice- but it's face centered cubic. (Rotate it, and you'll see it.) —Preceding unsigned comment added by 129.2.217.75 (talk) 06:13, 16 September 2008 (UTC)

The only thing you can say here is that the displayed hexagonal unit cell is not a primitive cell, since it contains more than one atom. At least that's true for a lattice with only one type of atoms <- TUU (The Unregistered User)

about calculating lattice point

`wat are the proceedure to take wen calc the lattice point of an atom . —Preceding unsigned comment added by 80.78.17.114 (talk) 14:53, 13 April 2009 (UTC)

incorrect definition

I know Ashcroft and Mermin use this definition, but really it is not right. Bravais refers to lattice *types*. What is defined here is simply a lattice. —Preceding unsigned comment added by 129.67.66.134 (talk) 20:18, 11 February 2011 (UTC)

why there are only 14 bravais lattices???

Can someone explain to a physics student, why there are only 14 bravai lattices? I dont understand what constrains the number of possible lattice types? I have seen pictures that explained to me, why no pentagons or heptagons can fill the 2D space... It must have something to do with that. But then I don't understand why there are face-centered or body-centered lattice types. What is the difference of a sc lattice and a bcc lattice. I could use the sc lattice and 2 atomic basis or not? --85.178.145.181 (talk) 17:33, 11 August 2011 (UTC)

Read Ashcroft-Mermin book, it explains this in the Bravais latice chapter. Pentagons are reserved for quasi-crystals. Spiralciric (talk) 13:15, 15 November 2012 (UTC)

Zero-dimensional space

"In zero-dimensional and one-dimensional space, there is only one type of Bravais lattice."

Is it helpful or meaningful to mention zero-dimensional space in this sentence at all? The intended meaning appears to be that the single point is the only possible "lattice" in zero dimensions, but I'm not entirely convinced that that qualifies as a lattice. --SoledadKabocha (talk) 04:12, 24 October 2015 (UTC)

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Reference, please

In the secton 'Unit cell, this sentence appears:

" (A crystal is a lattice and a basis at every lattice point.)"

without a reference, not even to the Wikipedia article on crystals.

I hope someone call fix this omission.

(I am not a crystallographer, but I have never seen a definition of crystal that includes this "basis at every lattice point".

Are there any further restrictions on the type of basis at each point, or on the way they vary point to point?

I hope someone knowledgeable on this subject can clarify this issue.