This is the table
\documentclass{article}
\usepackage{array}
\newcolumntype{C}{>{$}c<{$}}
\usepackage[skip=0.333\baselineskip]{caption}
\usepackage{booktabs,
amsmath,
siunitx}
\usepackage{txfonts}
\begin{document}
\begin{table}
\caption{Estimated mass of the three Itokawa particles with taking into account their porosity}
\label{Tab3}
\centering
\begin{tabular}{@{} l CCCCC @{}}
\toprule
Sample & Silicate density (g/ (\mu m^3)) & Volume (\mu m^3) & Estimated mass (g) & Porosity (%) & Estimated mass with considering the porosity (g) \\
\midrule
RA-QD02-0014 & 2.196 \times 10^(-12) & 125921 &2.7652 \times10^(-7) & 0.7 & 2.7458 \times 10^(-7) \\
RA-QD02-0023 & 2.196 \times 10^(-12) & 781081 & 1.7153 \times10^(-6) & 0.0 & 1.7153 \times 10^(-6) \\
RA-QD02-0047 & 2.196 \times 10^(-12) & 148570 & 3.2626\times 10^(-7) & 0.0 & 3.2626 \times 10^(-7) \\
\bottomrule
\end{tabular}
\end{table}
\end{document}
and the error
! Misplaced \noalign. \midrule ->\noalign {\ifnum 0=`}\fi \@aboverulesep =\aboverulesep \global \@... l.283 \midrule ?
Best Answer
You should use
siunitx
facilities. I suggest a legend for the table columns, instead of those long headers.