Wikipedia:WikiProject Chemistry/Structure drawing

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This page provides guidelines for drawing chemical structures, diagrams, and reaction schemes, as agreed by the structure drawing workgroup.
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WP:CSDG
WP:Chem/Structures

Representations of chemical structural formulae (such as skeletal formulae) form a major part of many chemistry articles. The chemistry community on Wikipedia has developed the following guidelines as part of their overall style guidelines. There is also a special image request page for chemical structure diagrams: structures may also be requested by placing {{Chemical drawing needed}} on the article's talk page (not on the article itself, please).

Contents

[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). If you choose to use regular vector-graphics programs to create your images, be aware that the results rendered by Wikimedia may differ from the output of your program. You therefore do this at your own risk, and may not get support from other editors. Advice on this process is being compiled here.
  • If you are able to generate high quality .SVG images, please feel free to upload them. However, there are certain bugs — view them on Wikipedia before making any changes to pages.
  • If you are not able to upload good SVGs, or if they do not turn out "right", they should be uploaded in the .PNG format. Never upload a non-photographic diagram as .JPG.
  • 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 other than required structural/atom labels. 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 labelling 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 as templates in the chemical drawing programs 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] Drawing in IsisDraw

Note:IsisDraw is available free to educators and students (with registration) from MDLI. Unfortunately, the "Export" commands are unreliable, often producing unreadable image files (TIFF, JPG, WMF). Therefore, to be converted to image files, IsisDraw drawings often need to be printed on a laser printer and scanned (using at least 300dpi), and some loss of quality is inevitable. Alternatively, the image file may be generated by using MS' Copy feature, followed by a Paste into another program. Photoshop Elements or Paint may be used. The image can then be saved as a .PNG file.

  • From the "Options" menu choose "Read Journal or Custom Settings" then "JACS". These ACS settings are as shown above for ChemDraw.
  • From the "Options" setting choose "Settings" then under "Chemical Drawing" select hydrogen labels "On hetero" in place of "None". Under "Line/Fill Arrow" select "Transparent" in place of "Opaque". If necessary "Apply settings".
  • Draw the desired structure/scheme, then (assuming export as TIFF or WMF fails) print using a high quality laser printer.
  • Scan in the image using 300 dpi.
  • Open using an image editor such as The Gimp or Irfan View, then add border and save as described below.
  • It is also possible to use the lasso tool to select your molecule, and then copy and paste it into another program, such as adobe photoshop.

[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).
ChemDraw / ChemBioDraw 11 (2007) cannot save black and white TIFF images. Therefore, save as a 1200 dpi greyscale TIFF image and decrease the color depth to 2 bit (black and white) during image processing.
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: please add {{PD-self}} to release the image into the public domain in addition to the obligate {{GFDL-self-no-disclaimers}}[1] (see GFDL). Images released under "non-commercial use only" licences are not accepted and will be deleted without warning, as will images without a tag.

{{Information
| Description=Chemical structure of [[:en:...|...]]
| Source=Selfmade
| Date= 10 June 2008
| Author=[[:en:User_talk:...|...]]
| Permission= {{GFDL-self-no-disclaimers}} <!-- see [[Wikipedia:GFDL_standardization]] --> {{PD-self}}
| other_versions=
}}

== Comments ==

High-resolution black/white .PNG made with [[:en:ChemDraw|ChemDraw]] and [[:en:IrfanView|IrfanView]] — see [[:en: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]]
  • Replace the "..." with the Wikipedia article name and your username, respectively
  • The date is already set to the current date
  • Browse to your file and select it. Optionally, change the final image name in the box below
  • Do not select a licensing from the upload form — 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

[edit] Templates

The following templates can be used on Wikipedia and the Commons to mark wrong or poor chemical structures:

Wikipedia: {{Template:Disputed diagram|reason}}

Commons: {{Template:Disputed diagram|reason}}
The factual accuracy of this diagram is disputed.
Page last edited 9 days ago
The dispute is about: reason.
Please discuss the issue on this diagram's talk page.
Wikipedia: {{Template:Disputed chem|reason}}

Commons: {{Template:Disputed chem|reason}}
The factual accuracy of this chemical structure is disputed.
Page last edited 9 days ago
The dispute is about: reason.
Please discuss the issue on this diagram's talk page.
See also: Wikipedia structure drawing guide.
Wikipedia: {{Template:Low quality chem|reason}}

Commons: {{Template:Low quality chem|reason}}
The quality of this chemical structure is disputed.
Page last edited 9 days ago
The dispute is about: reason.
Please discuss the issue on this diagram's talk page.
See also: Wikipedia structure drawing guide.

[edit] See also

[edit] External links

[edit] Notes

  1. ^ {{GFDL-self-no-disclaimers}} should be used for a short period until {{GFDL-self}} has been adjusted, see Wikipedia:GFDL_standardization
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