Chemical 'standard conditions' symbol

[Saajan Singh Chana]

Hi,

I need to use the 'standard conditions' symbol in a chemistry report.
This looks rather like a 'London Underground' sign (a circle with a
horizontal line through the middle extending slightly beyond the edge
of the circle).

_______
/ \
/ \
| |
--+----------+--
| |
\ /
\_______/

(please excuse my dismal attempt at ASCII art!)

I have tried to do this using the following LaTeX command:

\newcommand{\stdcond}{\ensuremath{\mathbin{\settowidth{\dimen7}
{\mbox{\textthreequartersemdash}}
\makebox[\dimen7][c]{$\circ$}
\makebox[0pt][r]{\textthreequartersemdash}}}}

This works fine in normal text; however when I try to put it into a
heading like this:

\section{Finding $\Delta E^{\stdcond}$}

LaTeX produces hundreds of errors, for example 'Missing \endcsname
inserted', 'Use of \@makepicbox doesn't match its definition',
'Argument of \@sect has an extra }', 'Paragraph ended before \@sect
was complete'.

These errors recur many times, and no output is produced. I don't
know enough about LaTeX to see what's going on! I would be grateful
if anyone could suggest a better way to do what I want.

Saajan

[Donald Arseneau]

saa...@saajmin.f9.co.uk (Saajan Singh Chana) writes:

> I need to use the 'standard conditions' symbol in a chemistry report.

Ha. Whan I was posting \moverlay just a little while ago, I thought
of posting this as well. Can you remind me: what are the differences
between the three standard-state notations?

^0
^\circ
^\barcirc

Given \moverlay (which is fragile)

%------------------------------------------------------------------------------
% Generic math-overlay macro: \moverlay{\backslash \cr /\cr \hbox{---}}
% (Yes, use \cr to separate items; this is for use in defining composite
% symbols, not for direct use in a document.)

\def\moverlay{\mathpalette\mov@rlay}
\def\mov@rlay#1#2{\leavevmode\vtop{%
\baselineskip\z@skip \lineskiplimit-\maxdimen
\ialign{\hfil$#1##$\hfil\cr#2\crcr}}}

Define:

\newcommand\barcirc{\protect\moverlay{\circ\cr-}}

I had actually been using a fragile version of \barcirc, which
needed explicit \protect when used in captions or titles, but
better to define it with \protect included.

Donald Arseneau as...@triumf.ca

[Saajan Singh Chana]

Donald Arseneau wrote:
> saa...@saajmin.f9.co.uk (Saajan Singh Chana) writes:
>
>
>>I need to use the 'standard conditions' symbol in a chemistry report.
>
>
> Ha. Whan I was posting \moverlay just a little while ago, I thought
> of posting this as well. Can you remind me: what are the differences
> between the three standard-state notations?

Thank you for both replies. Donald: I'm afraid that I don't know what
the difference is, as I am just an 'A' level chemistry student and the
only symbol used in my course is the 'underground' one.

Thanks again for the replies,

Saajan