title: Experimental charge density evidence for pnicogen bonding in a crystal of ammonium chloride.
abstract: Chemical binding in crystalline ammonium chloride, a simple inorganic salt with an unexpectedly complex bonding pattern, was studied by using a topological analysis of electron density function derived from high-resolution X-ray diffraction. Supported by periodic quantum chemical calculations, it provided experimental evidence for weak σ-hole bonds (1.5 kcal mol(-1) ) that involve ammonium cations in a crystal. Our results show this type of supramolecular interaction to be more numerous than has been found to date by using gas-phase calculations or statistical analysis of CSD.
authors.affiliation: X-ray Diffraction Centre and Quantum Chemistry Department, A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, 119991, Vavilova Str. 28, Moscow (Russia). unelya@xrlab.ineos.ac.ru.
authors.forename: Yulia V
authors.initials: YV
authors.lastname: Nelyubina
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Korlyukov
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Lyssenko
keywords: X-ray diffraction; electron density distribution; pnicogens; sigma-hole interactions; topological analysis