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A Molecular Octafluoridoneptunate(IV) Anion in (NH 4 ) 4 [NpF 8 ] and Theoretical Investigations of the [ M F 8 ] 4 – System ( M = Th – Bk)
Author(s) -
Scheibe Benjamin,
Patzschke Michael,
März Juliane,
Conrad Matthias,
Kraus Florian
Publication year - 2020
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.202000565
Subject(s) - chemistry , square antiprism , hydrofluoric acid , crystallography , lattice energy , neptunium , ammonium fluoride , crystal structure , hydrogen bond , aqueous solution , ion , hydrate , inorganic chemistry , actinide , molecule , organic chemistry , lanthanide
Olive‐green single crystals of ammonium octafluoridoneptunate(IV), (NH 4 ) 4 [NpF 8 ], were obtained by converting NpO 2 to a green neptunium tetrafluoride hydrate with hydrofluoric acid and subsequent treatment of the fluoride with an aqueous NH 4 F solution. The crystal structure of the compound was determined by single‐crystal X‐ray diffraction and observed to be isotypic to the uranium analogue. In (NH 4 ) 4 [NpF 8 ], molecular [NpF 8 ] 4– anions, which can either be described as a distorted square‐antiprism or a bicapped trigonal prism, are present which are bound to the NH 4 + ions via N–H ··· F hydrogen bonds. Quantum‐chemical calculations of [ M F 8 ] 4– anions show that the M –F bonds are highly ionic and the energy differences between different ligand arrangements likely can be overcome by lattice energies of different crystal structures in the solid state.