View source for Template:Chem/doc

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==Template instructions==
This template serves to simplify the writing of chemical formulae.  For example,
<pre>
{{chem|H|2|O}}
</pre>
will yield:
: {{chem|H|2|O}}

===Algebraic expression as subscript===
Algebraic expression are rendered as subscripts (but must not contain upper case letters).
<pre>
{{chem|C|''n''|H|2''n''&amp;nbsp;+&amp;nbsp;2}}
</pre>
gives
: {{chem|C|''n''|H|2''n''&nbsp;+&nbsp;2}}

===Charge===
Ion charge superscripts are also supported:
<pre>
{{chem|H|3|O|+}}
</pre>
yields:
: {{chem|H|3|O|+}}

Simultaneous subscripts/superscripts are automatically handled (use a hyphen for the minus sign):
<pre>
{{chem|SO|4|2-}}
</pre>
gives:
: {{chem|SO|4|2-}}

===Atomic number and mass number===
The first parameter can be used for mass number.
<pre>
{{chem|4|He}}
</pre>
gives:
: {{chem|4|He}}

The first two parameters can be used for mass number and atomic number.
<pre>
{{chem|4|2|He}}
</pre>
gives:
: {{chem|4|2|He}}

;Note: 
:Only the first two parameters can handle two consecutive plain numbers (i.e. without a plus sign or a hyphen (<code>+</code> or <code>-</code>) following). Otherwise the template will loop.

===Linking===
The optional parameter <tt>link</tt> changes the formula into a link. For example:
<pre>
{{chem|link=w:water|H|2|O}}
</pre>
will yield:
: {{chem|link=w:water|H|2|O}}

For linking individual elements can be linked in the following manner.
<pre>
{{chem|[[w:Hydrogen|H]]|2|[[w:Oxygen|O]]}} 
</pre>
gives 
: {{chem|[[w:Hydrogen|H]]|2|[[w:Oxygen|O]]}}

==Notes==
*To include "=" in the formula, use "&amp;#61;" For example, "<nowiki>{{chem|CH|2|&amp;#61;CH|2}}</nowiki>" yields {{chem|CH|2|&#61;CH|2}}.

*The template accepts up to twenty parameters in addition to <code>link</code>.
*This template uses {{tl|su}}.

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