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The Long‐Periodic Loop‐Branched Chain Structure of the Oxonitridophosphate La 21 P 40 O 46 N 57 , Elucidated by a Combination of TEM and Microfocused Synchrotron Radiation
Author(s) -
Nentwig Markus,
Kloß Simon D.,
Neudert Lukas,
Eisenburger Lucien,
Schnick Wolfgang,
Oeckler Oliver
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201902873
Subject(s) - monoclinic crystal system , crystallography , crystal structure , transmission electron microscopy , diffraction , single crystal , lanthanum , materials science , chemistry , nanotechnology , physics , inorganic chemistry , optics
Abstract The lanthanum oxonitridophosphate La 21 P 40 O 46 N 57 was synthesized by high‐pressure metathesis from partially hydrolysed LiPN 2 and LaCl 3 at 750–950 °C and 7–9 GPa. The combination of transmission electron microscopy (TEM) and diffraction using microfocused synchrotron radiation revealed a monoclinic crystal structure (space group P 2 1 / n , a= 14.042(4), b= 7.084(3), c= 41.404(10) Å, β =97.73(3)° and Z =2), which is characterized by loop‐branched 21 member single chains of P(O,N) 4 tetrahedra that extend along [2 0 1]. These chains are related to the loop‐branched dreier single chains with dreier ‐ring loops in stillwellite (CeBSiO 5 ). In La 21 P 40 O 46 N 57 , these chains are characterized by a complex long‐periodic conformation and exhibit disorder that involves La/N and P split positions. This is an extraordinarily long periodicity with respect to branched single chains of tetrahedra. La 21 P 40 O 46 N 57 constitutes the first rare‐earth oxonitridophosphate exhibiting a chain structure. Single‐crystal data are consistent with electron and powder X‐ray diffraction.