chemistryleft-superscripts
I am trying to denote a 28Si isotope. I used
$^{28}Si$. In the output, the chemical symbol is in italics, also there is an unnecessary space between the symbol and the nucleon number.
How do I get the chemical symbol 'Si' in roman, and the superscript and symbol a bit closer? I will use this code to denote a label in a Python code graph.
Bundling my comments into an answer:
I wrote »There is no way to make chemfigs bonds all the same length. Quoting part II section 4 Length of a bond of chemfig's manual:«
Rather than speaking of length of a bond, we should use the term interatomic spacing. If effect, only the interatomic spacing is adjustable with \setatomsep as we have seen on page 6. Once this parameter is set, the length of a bond depends on the content of atoms and, to a lesser extent, the angle the bond makes with the horizontal. It should be obvious that two “slimmer” atoms will have larger edge separations than two which are larger.
While this was true at the time I wrote my comment meanwhile there has been an update to chemfig. Since version 1.1 the following is possible:
When a star follows the macro
\chemfig*, the bonds have a fixed length and therefore, the distance between center to center atoms becomes variable. The macro\enablefixedbondlengthmakes this behavior valid for all macros (starred or not) while\disablefixedbondlengthgoes back to the default behavior. [...] In rings, even with starred\chemfig*, the default behaviour is restored in order to draw regular polygons.
Regarding your second point part III section 4 Vertical alignment has some information. It will not be immediately helpful, though, I guess. Nonetheless it is important information. The solution for the formula in your question is simple, though: write your formula in a different way:
\chemfig{CH_3-C(=[6]O)-CH3}
Keep in mind that the first atom in a formula determines the baseline of the whole formula.
As for your third point I recommend reading the blog post “Exploring ChemFig: Customising appearance” of our own @JosephWright which explains a method of how to use mhchem's \cf inside chemfig's \printatom. The crucial part is a redefinition of \CF@node@content
\makeatletter
\def\CF@node@content{%
\expandafter\expandafter\expandafter
\printatom\expandafter\expandafter\expandafter
{\csname atom@\number\CF@cnt@atomnumber\endcsname}%
\ensuremath{\CF@node@strut}%
}
\makeatother
which then allows \renewcommand*{\printatom}[1]{{\sffamily\cf{#1}}}
for example.
So far I got this
elements.txt.1/30,34/24,66/24,98/14,130/14 and 2,2,6,2,6,2,10,6,2,10,6,2,14,10,6,2,14,10,6,2. Perhaps they are encoded in a most efficient manner.
\documentclass[tikz,border=9]{standalone}
\begin{document}
% Draw the Contour of Groups
\def\DrawGroup;{
\draw[rounded corners=10pt,fill=red!10 ](15in,0)|-+(-1in,1in)|-+(1in,-6in)|-cycle;
\draw[rounded corners=10pt,fill=yellow!50](17in,-2in)rectangle+(10in,-4in);
\draw[rounded corners=10pt,fill=green!10 ](17in,-7in)rectangle+(14in,-2in);
\draw[rounded corners=10pt,fill=blue!10 ](33in,-0in)-|+(-5in,-6in)-|+(1in,1in)-|cycle;
\clip[rounded corners=10pt] (15in,0)|-+(-1in,1in)|-+(1in,-6in)|-cycle
(17in,-2in)rectangle+(10in,-4in)
(17in,-7in)rectangle+(14in,-2in)
(33in,-0in)-|+(-5in,-6in)-|+(1in,1in)-|cycle;
}
% Atomic Number \PNn => Coordinate (\PNx,\PNy)
\def\PositionByNumber;{
\pgfmathtruncatemacro\PNn{\n}
\foreach\PNa/\PNb in{1/30,34/24,66/24,98/14,130/14}{
\ifnum\PNn>\PNa
\pgfmathtruncatemacro\PNn{\PNn+\PNb}\xdef\PNn{\PNn}
\fi
}
}
% Coordinate (\PNx,\PNy) => Move and Group
\def\GroupByPosition;{
\pgfmathtruncatemacro\PNx{mod(\PNn-.5,32)+.5}
\pgfmathtruncatemacro\PNy{(\PNn-\PNx)/32}
\ifnum\PNx>2\ifnum\PNx<17
\pgfmathtruncatemacro\PNy{\PNy+3}
\pgfmathtruncatemacro\PNx{\PNx+14}
\fi\fi
\ifnum\PNx<3
\pgfmathtruncatemacro\PNx{\PNx+13}
\fi
\ifnum\PNx>26\ifnum\PNy<8
\pgfmathtruncatemacro\PNx{\PNx+1}
\fi\fi
\pgftransformreset;\pgftransformxshift{\PNx in};\pgftransformyshift{-\PNy in};
}
% Atomic Number \APn => Electron Configuration \APe1 \APe2 \APe3 ...
\def\AufbauPrinciple;{
\pgfmathtruncatemacro\APn{\n}
\xdef\APi{0}
\foreach\APa in{2,2,6,2,6,2,10,6,2,10,6,2,14,10,6,2,14,10,6,2}{
\pgfmathtruncatemacro\APi{\APi+1}\xdef\APi{\APi}
\ifnum\APn>\APa
\expandafter\xdef\csname APe\APi\endcsname{$\bullet$}
\pgfmathtruncatemacro\APn{\APn-\APa}\xdef\APn{\APn}
\else\ifnum\APn>0
\expandafter\xdef\csname APe\APi\endcsname{\APn}
\pgfmathtruncatemacro\APn{\APn-\APn}\xdef\APn{\APn}
\else
\expandafter\xdef\csname APe\APi\endcsname{}
\fi\fi
}
}
% Print the Configuration
\def\DrawConfiguration;{
\xdef\DCi{0}
\foreach\DCa/\DCb in{1/1,1/2,2/2,1/3,2/3,1/4,3/3,2/4,1/5,3/4,2/5,1/6,4/4,3/5,2/6,1/7,4/5,3/6,2/7,1/8}{
\pgfmathtruncatemacro\DCi{\DCi+1}\xdef\DCi{\DCi}
\path[scale=.2](\DCa,\DCb)node{\csname APe\DCi\endcsname};
}
}
\newread\linereader
\def\foreachline#1#2{\openin\linereader=#1\nextline#2}
\def\nextline#1{\read\linereader to \line\ifeof\linereader\closein\linereader\else\expandafter#1\line\end\expandafter\nextline\expandafter#1\fi}
\def\element#1 #2 #3 #4 #5\end{
\xdef\n{#1}
\PositionByNumber;
\GroupByPosition;
\draw[black](0,0)rectangle(1in,1in)
(0,1in)node[below right]{#1}(1in,1in)node[below left]{#4}(.5in,.5in)node{\Large #2}(.5in,.1in)node{#3};
\AufbauPrinciple;
\DrawConfiguration;
\message{[\n]}
}
\scriptsize
\begin{tikzpicture}
\DrawGroup;
\foreachline{elements.txt}\element
\end{tikzpicture}
\end{document}
Best Answer
I'm not sure how nobody has posted mhchem, the canonical chemistry package! Straight from the manual, section "Isotopes":
(
\cestands for "chemical equation" and can be used in either math or text mode.)If you're doing other stuff with chemistry, this is the package you want. Check out the docs!