# Why does the equation tag moves when using \hspace?

I am using align environment and sometimes can see that there is an unwated space in some parts of the aligned equations. Hence, I use \hspace with negative length to get the desired spacing.

Even though it works well for the equation itself, the tag sometimes moves horizontally with an amount equal to the argument of \hspace.

Here is a sample. Before

After

The tag of some other equations seem to stay where it should be even after using \hspace

This is What is the difference that made one set of equation affect the tags but the other set work well?

Source code

\documentclass{IEEEtran}

\usepackage[T1]{fontenc}
\usepackage[no-math]{fontspec}
\usepackage{amsmath,amsfonts}
\usepackage{mathtools}
\usepackage[symbolmisc]{mathastext}
\usepackage{blindtext}

\begin{document}
\blindtext
\begin{align}
&& \frac{X_{th, kp} - X_{b}} {\chi} > \frac{X_{th, kp}} {\chi} & \implies & \frac{1}{\Theta} &> \frac{1}{\Xi} &&
\notag
\\
&& &
\implies & \Theta &< \Xi &&
\end{align}
\blindtext
\begin{align}
&& \frac{X_{th, kp} - X_{b}} {\chi} > \frac{X_{th, kp}} {\chi} & \implies \hspace{-10mm} & \frac{1}{\Theta} &> \frac{1}{\Xi}
\notag
\\
&& &
\implies \hspace{-10mm} &  \Theta &< \Xi
\end{align}
\blindtext
\begin{align}
I_{sc} & = I_{sc, ref} & \hspace{-11mm} \bigg[  1 + \frac{\alpha}{100} (T_{op}-T_{ref}) \biggl]
\vspace{2 mm}
\\
V_{oc} & = V_{oc,ref} & \hspace{-11mm} \bigg[  1 + \frac{\beta}{100} (T_{op}-T_{ref}) \biggl]
\vspace{2 mm}
\\
P_{mp} & = P_{mp,ref} & \hspace{-11mm} \bigg[  1 + \frac{\gamma}{100} (T_{op}-T_{ref}) \biggl]
\end{align}
\end{document}

• off topic: instead of using \vspace{2 mm}\\  you can use \\[.5em] for example, to increase space between lines. – Sigur Aug 23 '18 at 20:22
• why are you starting each row with && ? – David Carlisle Aug 23 '18 at 20:28
• unrelated but \bigg[ ...\biggl] should be \biggl[ ...\biggr] – David Carlisle Aug 23 '18 at 20:30
• also your packages seem inconsistent you have \usepackage[T1]{fontenc} \usepackage[no-math]{fontspec} but T1 encoding should only be used with (pdf)latex but fontspec requires xetex or luatex, which tex engine are you using? – David Carlisle Aug 23 '18 at 20:33
• Since you have some responses below that seem to answer your question, please consider marking one of them as ‘Accepted’ by clicking on the tickmark below their vote count (see How do you accept an answer?). This shows which answer helped you most, and it assigns reputation points to the author of the answer (and to you!). It's part of this site's idea to identify good questions and answers through upvotes and acceptance of answers. – user36296 Mar 12 at 10:00

The negative spacing was only being used to correct for space forced by the extra &, if the alignment is marked with a single & as usual then a far more natural spacing is used

I removed fontspec here so the example can be used with pdflatex

\documentclass{IEEEtran}

\usepackage{amsmath,amsfonts}

\usepackage{blindtext}

\begin{document}
\blindtext
\begin{align}
\frac{X_{th, kp} - X_{b}} {\chi} > \frac{X_{th, kp}} {\chi} & \implies \frac{1}{\Theta} > \frac{1}{\Xi}
\notag
\\
&\implies  \Theta < \Xi
\end{align}

\end{document}

• Thanks for the answer, but I still want to align the inequality signs precisely with each other and I think I knew how – Al-Motasem Aldaoudeyeh Aug 23 '18 at 20:55
• @Al-MotasemAldaoudeyeh if you really want that you could use alignat (but still you don't need && at the start of every row, and do not need negative s[ace) – David Carlisle Aug 23 '18 at 20:57