I ran into a problem with “! Misplaced \omit” error. I have searched quite hard to find the relevant problem but only find mine is similar with bigbadpiano's question in which A.Ellett generated a nice table with WME.
However, my personal desire is to put one multicolumn as black background and white text, for instance: 
This is an failed example since the whole first row should be black. I also get an error in Log File:" ! Misplaced \omit. \multispan ->\omit \@multispan l.10 ...multicolumn{8}{|c|}{\BlackCell{Dataset A}} \\hline I expect to see \omit only after tab marks or the \cr of an alignment. Proceed, and I'll ignore this case."
If this question is duplicate, I am really sorry but I couldn't find the correct answer to my specific problem. In this case, please inform me the exact answer and I will delete this question later. Any help is appreciated.
\documentclass{article} \pagestyle{empty} \usepackage[table]{xcolor} \newcommand\BlackCell[1]{% \multicolumn{1}{c}{\cellcolor{black}\textcolor{white}{#1}} } \begin{document} \begin{table}[h] \begin{tabular}{|c|c|c|c|c|c|c|c|}\hline \multicolumn{8}{|c|}{\BlackCell{Dataset A}} \\\hline L (m) & T (s) & T$^2$ (s$^2$) & L$^{1/2}$ (m$^{1/2}$) & $\Delta$T$^2$ (s$^2$) & $\Delta$T (s) & Fitted T$^2$ (s$^2$) & Fitted T (s) \\ \hline 0.2 & 0.626 & 0.392 & 0.447 & 0.006 & 0.005 & 0.394 & 0.662 \\ 0.3 & 0.889 & 0.790 & 0.548 & 0.009 & 0.005 & 0.797 & 0.889 \\ 0.4 & 1.105 & 1.221 & 0.632 & 0.011 & 0.005 & 1.201 & 1.081 \\ 0.5 & 1.261 & 1.590 & 0.707 & 0.013 & 0.005 & 1.604 & 1.250 \\ 0.6 & 1.420 & 2.016 & 0.775 & 0.014 & 0.005 & 2.008 & 1.403 \\ 0.7 & 1.555 & 2.418 & 0.837 & 0.016 & 0.005 & 2.411 & 1.543 \\ 0.8 & 1.679 & 2.819 & 0.894 & 0.017 & 0.005 & 2.814 & 1.674 \\ 0.9 & 1.798 & 3.233 & 0.949 & 0.018 & 0.005 & 3.218 & 1.797 \\ 1.0 & 1.901 & 3.614 & 1.000 & 0.019 & 0.005 & 3.621 & 1.913 \\ 1.1 & 2.000 & 4.000 & 1.049 & 0.020 & 0.005 & 4.025 & 2.023 \\\hline \end{tabular} \end{table} \end{document} 
