My following MWE works in general but it returns a white space after the second column in the light grey head row. I can avoid this if I don't apply the \mcxcommand on the column content ("Copolymer (Versuchsnummer)") but then I can't perform a \linebreakor \par anymore. The \parcommand works within the \mcxcommand but results in producing a white space between the 2nd and the 3rd cell of the first row (see attached picture) since the content in the second column is too wide.
Can help me adjusting the width of the second column to fit the content's width? But it is very important to me that columns 3-6 keep the same width while the table still fits the line width!
Thanks a lot Cheers Benson_G
\usepackage[onehalfspacing]{setspace} %Zeilenabstand
\usepackage[hmargin={3cm,2cm},vmargin=2cm, includehead]{geometry}%Maße für die wissenschaftliche Arbeit
\usepackage[parfill]{parskip} %Bessere Seitenumbrüche
\usepackage[T1]{fontenc} %Silbentrennung
\usepackage[german]{babel} %Sprachanpassungen
% \usepackage[utf8]{inputenc} %Direkte Angabe von Umlauten möglich
\usepackage{csquotes}
\usepackage{graphicx} %Einfügen von Bildern
% \usepackage{tabularx} %Tabellen
% \usepackage{booktabs} %Weitere Möglichkeiten für Tabellen
\usepackage{here} %Lage von Tabellen und Bildern
\usepackage{physics}
\usepackage{amsmath}
\usepackage{mathrsfs}
\usepackage{textgreek}
\usepackage{textcomp}
\usepackage{amssymb}
% \usepackage[labelformat=simple]{subcaption}
\usepackage{float}
\usepackage{pdfpages}
\usepackage{lmodern}
\usepackage{enumitem}
\usepackage{parskip}
\usepackage[hyphens]{url} % be sure to specify the option 'hyphens'
% \usepackage[pdftex,bookmarksnumbered,hidelinks,breaklinks]{hyperref}
% \usepackage[superscript]{cite}
% ======SCHRIFTART=================================
% Schriftart Helvetica
\usepackage[scaled]{helvet}
\renewcommand\familydefault{\sfdefault}
% ===================================================
\usepackage[per-mode = reciprocal, output-decimal-marker={,}, exponent-product = {\cdot}]{siunitx} %Si-Einheiten
\usepackage[headsepline,automark, draft = false]{scrlayer-scrpage} %Für Kopf und Fußzeile und Seitenzahlen
\clearpairofpagestyles
\ihead{\headmark}
\rohead{\pagemark}
% \cfoot{\pagemark}
\addtokomafont{pageheadfoot}{\upshape}
\KOMAoptions{onpsinit={\linespread{1}\selectfont}}
%=======TABELLEN=====================================
\usepackage[column=O]{cellspace} % <-- new
\setlength\cellspacetoplimit{2pt}
\setlength\cellspacebottomlimit{2pt}
\addparagraphcolumntypes{X}
\usepackage{booktabs, tabularx}
\newcommand\mcx[1]{\multicolumn{1}{>{\centering\arraybackslash}X}{#1}}
\usepackage[version=4]{mhchem} % newest version
\usepackage{siunitx}% instead of units, which is deprecate
\usepackage[labelsep = period, skip=1ex, format=plain, font=small, labelfont=bf, justification = justified]{caption} % new
%\usepackage[labelformat=simple]{subcaption}
\usepackage{colortbl} % changed, instead of "color" and "colortbl"
\definecolor{hellgrau}{rgb}{0.90,0.90,0.90}
\definecolor{ExpBlau}{rgb}{0.11,0.19,0.46}
%=====================================================
%=====================================================
\begin{document}
\renewcommand{\tablename}{Tabelle}
\renewcommand{\figurename}{Abbildung}
\captionsetup[table]{justification = raggedright, font=normal, singlelinecheck=false}
\begin{table}[htb!]
\centering
\footnotesize
\setlength\belowcaptionskip{5 pt}
\renewcommand\tabularxcolumn[1]{m{#1}}
\caption{\textbf{Molekulare Eigenschaften der P(EO-\textit{co}-EPB)-Copolymere}}
\begin{tabularx}{\linewidth}{llcccc}
\rowcolor{hellgrau}
\vspace{0.2cm}
Probe
& \mcx{Copolymer \par (Versuchsnummer)}
& \mcx{$\textit{M}\text{n, NMR}$\par (g mol$^{\text{-1}}$)}
& \mcx{mol% EPB$^{\textcolor{ExpBlau}c}$}
& \mcx{$\textit{M}\text{n, GPC}$\par (g mol$^{\text{-1}}$)}
& \mcx{\textit{Đ}} \
\hspace{3mm} 1 & P(EO$_\text{141}$-\textit{co}-EPB$_\text{y}$) & & & & \\
\hspace{3mm} 2 & P(EO$_\text{58}$-\textit{co}-EPB$_\text{y}$) & & & & \\
\hspace{3mm} 3 & P(EO$_\text{x}$-\textit{co}-EPB$_\text{y}$) & & & & \\
\hspace{3mm} 4 & P(EO$_\text{x}$-\textit{co}-EPB$_\text{y}$) & & & & \\
\hspace{3mm} 5 & P(EO$_\text{x}$-\textit{co}-EPB$_\text{y}$) & & & & \\
\hspace{3mm} 6 & P(EO$_\text{x}$-\textit{co}-EPB$_\text{y}$) & & & & \\
\hspace{3mm} 7 & P(EO$_\text{x}$-\textit{co}-EPB$_\text{y}$) & & & & \\
\hspace{3mm} 8 & P(EO$_\text{x}$-\textit{co}-EPB$_\text{y}$) & & & & \\
\end{tabularx}
\vspace{0.6 \baselineskip} \\
\raggedright
$^{\textcolor{ExpBlau}a}$ Molekulargewicht aus $^\text{1}$H-NMR-Spektrum berechnet, $^{\textcolor{ExpBlau}b}$Molekulargewicht aus GPC, .
\label{tab:Copo}%
\vspace{-1.8 \baselineskip}
\end{table}
\end{document}
tabularxwithout a X column, just usetabularhere let the columns be natural width then the second column will be wide enough for its heading. – David Carlisle Nov 26 '20 at 11:58tabularxbecause I want to implement the overhang parameter ofcolumncolorlater as it's explained in the thread with its link attached. Since I've noticed that you have also commented on the thread I am referring to with the same piece of advice I assume you probably cannot help me with my problem.(https://tex.stackexchange.com/a/301036/229635) – Benson_G Nov 26 '20 at 12:36>{\hsize=1.5\hsize}or whatever is needed but really this is my code and I promise you tabularx is not helping you here. – David Carlisle Nov 26 '20 at 12:38