# Talk:Fractional coordinates

WikiProject Chemistry (Rated Start-class, Low-importance)
This article is within the scope of WikiProject Chemistry, a collaborative effort to improve the coverage of chemistry on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
Start  This article has been rated as Start-Class on the project's quality scale.
Low  This article has been rated as Low-importance on the project's importance scale.

## Inaccurate transformation matrix in "Conversion to cartesian coordinates" section

Serious errors - the matrix that is provided is not correct, it should be the transpose of given matrix. I think this should be pointed out. — Preceding unsigned comment added by 18.82.7.55 (talk) 22:26, 19 June 2012 (UTC)

Hi, 18.82.7.55, and thanks for your suggestion! Everyone is welcome to help improve Wikipedia (please see WP:BEBOLD). I've left more information on your talk page, but please feel free to drop a note on my talk page if I can help you with any editing questions. Cheers! -- Bgpaulus (talk) 22:34, 19 June 2012 (UTC)
In an attempt to direct discussion here, I've replaced 18.82.7.55's comments from this edit with the {{Expert-subject}} template at the top of the article. Cheers! -- Bgpaulus (talk) 23:29, 19 June 2012 (UTC)
I think the matrix is correct - I used it for my program and it works. I just don't like notations. I would write it
$\mathbf{\begin{bmatrix} x \\ y \\ z \\ \end{bmatrix} = \begin{bmatrix} a & b\cos(\gamma) & c\cos(\beta) \\ 0 & b\sin(\gamma) & c\frac {\cos(\alpha)-\cos(\beta)\cos(\gamma)} {\sin(\gamma)} \\ 0 & 0 & c\frac {v} {\sin(\gamma)} \\ \end{bmatrix}} \begin{bmatrix} x_{frac} \\ y_{frac} \\ z_{frac} \\ \end{bmatrix}$
Bor75 (talk) 22:12, 19 September 2012 (UTC)
There is nothing wrong with either of the matrices. I wrote a program using those matrices, and the results match the cif file coordinates and the coordinates output by the chemistry program Avogadro. — Preceding unsigned comment added by 146.186.25.18 (talk) 20:43, 29 January 2013 (UTC)

The matrices are correct; but not the matrix that is given on the cited angelfire.com page even though the way of derivation that is given there is correct. there only the ab prefactor of one term of c3 has to be removed. possible citation for the correct matrix: Mathematical techniques in crystallography and material science / Edward Prince / Springer 1994 (see chapter "metric tensor"). the definitions of the cited angelfire page are equal to the definitions here, there is just one error in calculus.

by the way: no chemist is needed here. every scientist can proof these matrices to be correct.

129.69.120.176 (talk) —Preceding undated comment added 08:41, 19 September 2013 (UTC)