Wikipedia:WikiProject Chemistry/Structure drawing

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This page represents guidelines for drawing chemical structures, diagrams, and reaction schemes, as agreed by the structure drawing workgroup.

1 Chemical structures and reaction schemes
2 See also

[edit] Chemical structures and reaction schemes

[edit] General

Please do not scan diagrams from books or other paper sources. Such scanned images are usually of low quality, and are in violation of the original copyright. Images should be prepared with a molecule editor (there are freeware molecule editors available for download). Please do not use regular vector-graphics programs for chemical images.
Currently, the images should be uploaded in the .PNG format. Never upload a non-photograpic diagram as .JPG. In the future, the images should be uploaded as scalable .SVG files, however, the recommended structure editors do not yet support this.
Please prepare your images much larger than the final size in order to avoid visible pixelation if printed or displayed. Chemical structures and reaction schemes compress to very small files compared with photos. Widths of ~ 1000 pixels (or around 720 dpi) are a good compromise, however, images wider than about 2000 pixels will cause heavy server load and might not be displayed at all.
Please save diagrams with a transparent background. That way the background can be defined by the page element that holds the image.
Please do not include text in your images. Text tends to reproduce very badly in the resizing of images, and images with English language text could not be used by other Wikipedia languages. Please do not use the abbreviation Me for CH₃: no space is saved, and there is a risk of ambiguity with the German abbreviation for Metall (metal).
Please ensure that your images are legible at either 250 pixel width (half page width in article) or 600 pixel width (full page width in article). Images that can be reduced to 250 pixel width (or lower) are preferred, as this simplifies the page formatting.
Indexes used for numbering must be superscript: R¹-CH₂-R² (not R₁-CH₂-R₂)

[edit] Suggested molecule editor settings

ACS settings should be used for both structures and reaction schemes. These settings are all available in templates in ChemDraw, Isis/Draw and ChemSketch. Please use sans-serif fonts like Arial.

[edit] Drawing in ChemDraw

From the "File" menu, choose "Apply document settings from -> ACS Document 1996".
Draw the structure, and save it as a ChemDraw file.
If you drew the structure before applying any settings, then you need to select the object, open the "Object" menu and choose "Apply document settings from -> ACS Document 1996".
Then save it as a TIFF file, to be read by an image editor such as The Gimp or Irfan View (see below for details).

The ACS settings are as follows:

Chain angle: 120 degrees
Bond spacing: 18% of length
Bond length: 0.508 cm (14.4 pt)
Bold width: 0.071 cm (2 pt)
Line width: 0.021 cm (0.6 pt)
Margin width: 0.056 cm (1.6 pt)
Hash spacing: 0.088 cm (2.5 pt)
Captions: Arial 10 pt
Atom labels: Arial 10 pt
Bond angles and length: "fixed" is recommended

Also recommended: For minus symbols on atoms, change the font for the minus symbol to "Symbol" for clarity.

[edit] Image processing

Most molecule editors cannot produce .PNG images directly with the requirements outlined above. The image processing step also allows a canvas (margin) to be added (this is usually absent from the molecule editor output).

Save as: TIFF black/white bitmap with a resolution of 720 dpi (small molecules) to 240 dpi (large molecules) (in ChemDraw under the Options button in the Save as TIFF dialog).

Image processing (Photoshop or Irfan view):

Add canvas of about 5% to each side (test it, usually around 30 pixels) (Photoshop: Image:Canvas Size, relative, 10% width, 10% height)
Save as a PNG black/white bitmap (color depth: 2) with transparent background.

[edit] Uploading and copyright

WikiProject Chemicals strongly encourages users to upload their images to the Wikimedia Commons and not to the English Wikipedia. This enables images to be used in other Wikipedia languages and other Wikimedia projects and makes updating images much easier. It is also simpler to find images in the Commons category structure compared to Wikipedia. To upload images to the Commons, you must be a registered user there. Please use the same username as on the English Wikipedia.

Images of chemical structures and reaction schemes are assumed to be copyrighted and uploaded images must have a correct copyright tag: either {{PD-self}} if you release the image into the public domain or {{GFDL-self}} if you release it under the GFDL. Images released under "non-commercial use only" licences are no accepted and will be deleted without warning, as will images without a tag.

Go to the upload page: http://commons.wikimedia.org/wiki/Special:Upload (you may want to bookmark this)
Paste this text to the summary template:

{{Information
| Description=Chemical structure of [[en:...|...]]
| Source=Selfmade
| Date= 31 March 2007
| Author=[[w:User_talk:...|...]]
| Permission=[[w:GNU Free Documentation License|GNU Free Documentation License]] (''GFDL''), [[w:Public domain|Public domain]]  (''PD'')
| other_versions=
}}

== Comments ==

High-resolution black/white .PNG made with [[w:ChemDraw|ChemDraw]] and [[w:IrfanView|IrfanView]] — see [[w:Wikipedia:WikiProject_Chemistry/Structure_drawing|WikiProject Chemistry - structure drawing]] for detailed instructions. Please drop me a note if you need the source file.

[[Category:Chemical structures]]

{{GFDL-self}}
{{PD-self}}

Replace the "..." with the Wikipedia article name and your username, respectively
Browse to your file and select it. Optionally, change the final image name in the box below
Do not select a licensing — the tags are already in the pasted text
Upload the file
Change your structure to the most specific subcategory (or subcategories) of Category:Chemical compounds