Molar-mass dispersity
= Molar-mass dispersity
{title2=$M_w/M_n$}
The <weight-average molar mass> divided by the <number-average molar mass>. Its conventional written symbol is Đ. With number weighting it equals $1+\operatorname{Var}(M)/\langle M\rangle^2$, so it is at least one and equals one only for a uniform <molar mass>. It measures one aspect of distribution breadth, not the full shape of a <molar mass> distribution.