Dedicated to Daniel Alpay on the occasion of his 60th birthdayThe paper treats several aspects of the truncated matricial [α, β]-Hausdorff type moment problems. It is shown that each [α, β]-Hausdorff moment sequence has a particular intrinsic structure. More precisely, each element of this sequence varies within a closed bounded matricial interval. The case that the corresponding moment coincides with one of the endpoints of the interval plays a particular important role. This leads to distinguished molecular solutions of the truncated matricial [α, β]-Hausdorff moment problem, which satisfy some extremality properties. The proofs are mainly of algebraic character. The use of the parallel sum of matrices is an essential tool in the proofs.Mathematics Subject Classification (2010): 44A60, 47A57.