Style guide for this Wiki

This page provides some guidance to authors on creating and marking up definitions.

Creating a new definition

The preferred method (to maintain a properly managed index of terms) is to navigate to the appropriate alphabetical index page (accessible through the main page):

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

Edit this page to add the new entry that you wish to work on in the form of a hyperlink, e.g. on the page for 'R' one could add

[[reciprocal space]]

IMPORTANT: use a lowercase initial letter, unless the term is itself a proper noun, e.g.

[[Miller indices]]

Now save the index page (the 'R' page that uou have been working on in this example). The new entry will appear as a hyperlink - if it is to a page that does not yet exist, it will show up in red. Now click on this new (red) hyperlink, and you will bring up an edit page where you can begin to enter the text of your new definition.

While you are editing the page, you can always click on the Show preview button to see what the formatted entry will look like, but remember that your work will not be saved until you click on the Save page button.

Intellectual content and overall structure

Each entry starts with the translation of the term in other languages (at present we are still experimenting with various formats suggested for doing so). The definition is then given, starting with a short statement as to what the object is, followed by a longer development as necessary. If the development is too long, it should be put in a separate page to which a link is given (see for instance the entries arithmetic crystal classes and Miller indices). A historical note can be added if it is useful. In 'See also', appropriate links to other entries or to IUCr resources (articles in the Journals, pamphlets, COMCIFS etc.) are given as well as references to the relevant chapters in International Tables. Generally speaking, one should always ask oneself: is the definition I am writing going to give the reader the answer he is looking for?

Each entry should be self-contained, and at the same time related to the others within a preconceived framework.

There is of course often a question as to whether a full definition of a rather general term should appear in a dictionary of crystallography, or in a dictionary of chemistry or physics. Our objective is to provide the information that a crystallographer would wish to know. 'chiral' may be considered a chemical term, but the reader who wants to know what 'chiral crystal' means ought to find the answer in our dictionary. A model definition might explain that the chirality of a crystal may either come from a structure built with achiral units (e.g. quartz, benzil) or from the chiral molecules that it contains (e.g. saccharose). It should have links to entries such as 'optical activity', 'gyrotropic', etc., and perhaps a historic note on Pasteur's experiment separating the left and right sodium ammonium tartrate crystals and the consequences for our understanding of enantiomers and racemates.

Formatting content

This information is an abbreviated set of tips from the relevant mediawiki help page.

<tr> <td>

• Leading spaces

Leading spaces are another way to preserve formatting. Putting a space at the beginning of each line stops the text from being reformatted. It still interprets Wiki markup and special characters: → </td> <td>

 Putting a space at the beginning of
 each line stops the text   from
 being reformatted. It still interprets
 Wiki markup and special characters: →

</td> </tr>

<tr> <td colspan="2">

Images and tables

</td> </tr>

<tr> <td> A picture, including alternate text:

You can put the image in a frame with a caption:

Darwin's theory

</td> <td>

A picture, including alternate text:

[[Image:Darwin.gif|Darwin's theory]]

You can put the image in a frame with a caption:

[[Image:Darwin.gif|frame|Darwin's theory]]

</td> </tr>

<tr> <td>

Emphasize text with two apostrophes on each side. Three apostrophes emphasize it strongly. Five apostrophes is even stronger.	''Emphasize text'' with two apostrophes on each side. Three apostrophes emphasize it '''strongly'''. Five apostrophes is '''''even stronger'''''.
A single newline has no effect on the layout. But an empty line starts a new paragraph.	A single newline has no effect on the layout. But an empty line starts a new paragraph.
You can break lines without starting a new paragraph.	You can break lines<br> without starting a new paragraph.
You can use HTML tags, too. Some useful ways to use HTML: Put text in a typewriter font. The same font is generally used for computer code. Strike out or underline text, or write it in small caps. Superscripts and subscripts: x2, x2 Invisible comments that only appear while editing the page. Comments should usually go on the talk page, though. HTML markup should be used sparingly, and only if it is difficult or impossible to achieve the desired result otherwise.	You can use <b>HTML tags</b>, too. Some useful ways to use HTML: Put text in a <tt>typewriter font</tt>. The same font is generally used for <code>computer code</code>. <strike>Strike out</strike> or <u>underline</u> text, or write it <span style="font-variant:small-caps"> in small caps</span>. Superscripts and subscripts: x<sup>2</sup>, x<sub>2</sub> Invisible comments that only appear while editing the page. <!-- Note to editors: blah blah. --> Comments should usually go on the talk page,though. HTML markup should be used sparingly, and only if it is difficult or impossible to achieve the desired result otherwise.
Section headings Headings organize your writing into sections. The Wiki software can automatically generate a table of contents from them.
Subsection More equals signs creates a subsection. A smaller subsection Don't skip levels, e.g. from two to four equals signs. Start with two equals signs; don't use single equals signs.	== Section headings == Headings organize your writing into sections. The Wiki software can automatically generate a table of contents from them. === Subsection === More equals signs creates a subsection. ==== A smaller subsection ==== Don't skip levels, (''e.g.'' from two to four equals signs. Start with two equals signs; don't use single equals signs.
Lists
Unordered lists are easy to do: Start every line with a star. More stars indicate a deeper level. A newline in a list marks the end of the list. Of course you can start again.	* ''Unordered lists'' are easy to do: ** Start every line with a star. *** More stars indicate a deeper level. * A newline * in a list marks the end of the list. * Of course you can start again.
Numbered lists are also good: Very organized Easy to follow A newline marks the end of the list. New numbering starts with 1.	# Numbered lists are also good: ## Very organized ## Easy to follow A newline marks the end of the list. # New numbering starts with 1.
You can make horizontal lines to separate text. But you should usually use sections instead, so that they go in the table of contents.	You can make horizontal lines to separate text. ---- But you should usually use sections instead, so that they go in the table of contents.
Links
Here's a link to a page named reciprocal space. You can put formatting around a link. Example: reciprocal space.	Here's a link to a page named [[reciprocal space]]. You can put formatting around a link. Example: ''[[reciprocal space]]''.
Link to a page section by its title: Ewald sphere#Definition Ewald sphere#History If multiple sections have the same title, add a number. #Example section 3 goes to the third section named "Example section".	Link to a page section by its title: * [[Ewald sphere#Definition]] * [[Ewald sphere#History]] If multiple sections have the same title, add a number. [[#Example section 3]] goes to the third section named "Example section".
Make a link point to a different place with a 'piped link'. Put the link target first, then the pipe character "|", then the link text. front page see below	Make a link point to a different place with a 'piped link'. Put the link target first, then the pipe character "|", then the link text. * [[Main_Page|front page]] * [[Ewald sphere#History|see below]]
Make an external link just by typing a URL: http://www.iucr.org Give it a title: IUCr or leave the title blank: [1]	Make an external link just by typing a URL: http://www.iucr.org Give it a title: [http://www.iucr.org IUCr] or leave the title blank: [http://www.iucr.org]
Category links don't show up, but add the page to a category. Add an extra colon to actually link to the category: Category:English documentation	Category links don't show up, but add the page to a category. [[Category:English documentation]] Add an extra colon to actually link to the category: [[:Category:English documentation]]
Just show what I typed A few different kinds of formatting will tell the Wiki to display things as you typed them.
<nowiki> tags The nowiki tag ignores Wiki ''markup''. It reformats text by removing newlines and multiple spaces. It still interprets special characters: →	<nowiki> The nowiki tag ignores Wiki markup. It reformats text by removing newlines and multiple spaces. It still interprets special characters: &rarr; </nowiki>
<pre> tags The pre tag ignores Wiki markup. It also doesn't reformat text. It still interprets special characters: →	<pre> The pre tag ignores Wiki markup. It also doesn't reformat text. It still interprets special characters: &rarr; <nowiki> </nowiki> </pre>

This	is
a	table

</td> <td>

{| border="1" cellspacing="0" cellpadding="5" align="center"
! This
! is
|- 
| a
| table
|}

</td> </tr>

<tr> <td colspan="2">

Mathematical formulas

</td> </tr> <tr> <td>

You can format mathematical formulas with TeX markup.

[math]\sum_{n=0}^\infty \frac{x^n}{n!}[/math]

</td> <td>

<math>\sum_{n=0}^\infty \frac{x^n}{n!}</math>

</td> </tr>

<tr> <td colspan="2">

Special characters

</td> </tr>

<tr> <td> Umlauts and accents:

À Á Â Ã Ä Å Æ Ç È É Ê Ë Ì Í Î Ï Ñ Ò Ó Ô Õ Ö Ø Ù Ú Û Ü ß à á â ã ä å æ ç è é ê ë ì í î ï ñ ò ó ô œ õ ö ø ù ú û ü ÿ </td> <td>

À Á Â Ã Ä Å
Æ Ç È É Ê Ë
Ì Í Î Ï Ñ Ò
Ó Ô Õ Ö Ø Ù
Ú Û Ü ß à á
â ã ä å æ ç
è é ê ë ì í
î ï ñ ò ó ô
œ õ ö ø ù ú
û ü ÿ

</td> </tr>

<tr> <td> Punctuation:

¿ ¡ « » § ¶ † ‡ • - – — </td> <td>

¿ ¡ « » § ¶
† ‡ • – —

</td> </tr>

<tr> <td> Commercial symbols:

™ © ® ¢ € ¥ £ ¤ </td> <td>

™ © ® ¢ € ¥ £ ¤

</td> </tr>

<tr> <td> Greek characters:

α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ σ ς τ υ φ χ ψ ω Γ Δ Θ Λ Ξ Π Σ Φ Ψ Ω </td> <td>

α β γ δ ε ζ
η θ ι κ λ μ ν
ξ ο π ρ σ ς
τ υ φ χ ψ ω
Γ Δ Θ Λ Ξ Π
Σ Φ Ψ Ω

</td> </tr>

<tr> <td> Math characters:

∫ ∑ ∏ √ − ± ∞ ≈ ∝ ≡ ≠ ≤ ≥ × · ÷ ∂ ′ ″ ∇ ‰ ° ∴ ø ∈ ∩ ∪ ⊂ ⊃ ⊆ ⊇ ¬ ∧ ∨ ∃ ∀ ⇒ ⇔ → ↔ ↑ ℵ ∉ </td> <td>

∫ ∑ ∏ √ − ± ∞
≈ ∝ ≡ ≠ ≤ ≥
× · ÷ ∂ ′ ″
∇ ‰ ° ∴ ø
∈ ∩ ∪ ⊂ ⊃ ⊆ ⊇
¬ ∧ ∨ ∃ ∀ ⇒ ⇔
→ ↔ ↑
ℵ ∉

</td> </tr>

</table>