Add to ORKGAuthor Institution: Department of Astronomy, University of Michigan, 500 Church; Street, Ann Arbor, MI 48109-1042Prestellar cores are unique laboratories to study the initial conditions of star formation. Over the past decade, extinction maps and millimeter emission observations have expended our knowledge of the physical structure (density, dust temperature), while millimeter line observations have increased our understanding of the chemistry in these cores. B68 is a representative example of these studies. In the past years, we have mapped extensively this core in different molecular lines. In this contribution, we will present new observations and modeling of the chemistry the cloud. We will show how, using a chemistry model coupled wi...