Structure–Function Relationships in Molecular Crystals ─ A Festschrift to Celebrate Mark A. Spackman

RecommendationsW ith careful modeling, molecular crystals are ideal systems to study how molecules interact with each other as a foundation for understanding their collective properties.Such knowledge is used in crystal engineering, and it forms the basis for developing specific functions or applications of molecular crystals.During his career, Professor Mark Spackman has made a substantial and very impactful journey through exactly those aspects of crystallography.He started from work on the multipole formalism to determine Xray electron density distributions (Valray software 1 ), and emphasis on the corresponding electrostatic properties of molecules led to models for atom-atom potentials 2 and for chemical properties based on the promolecule.3 He used that understanding to estimate electric moments of molecules in crystals, 4 as well as polarizabilities and refractive indices, 5 model interaction energies, 6 elastic tensors, 7 and many other properties of molecular crystals.Mark introduced a novel way to define molecular surfaces in crystals, along with their associated shapes and interactions, using electron density partitioning based on Hirshfeld's weight function.These are now widely known as Hirshfeld surfaces 8 �although they could just as well be called Spackman surfaces.Hirshfeld surface analysis 9 implemented in the software CrystalExplorer 10 has by now become a key tool in crystal engineering.Mark's outstanding career shows how diverse and versatile work with crystals can be, so Mark's 70th birthday is a perfect opportunity to showcase related work from around the globe under the theme "Structure-Function Relationships in Molecular Crystals".Mark Arthur Spackman was born in Tasmania, Australia, and after some time in Victoria and New Zealand, he came to Perth in Western Australia to study and complete his PhD under the supervision of Graham Chandler in 1979.A trip to Israel in 1977