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LiM 2 (NCN)Br 3 (M = Sr, Eu): Synthesis and Crystal Structures of Solid‐State Carbodiimides with Empty Tetrahedral Metal Entities
Author(s) -
Liao Wuping,
Dronskowski Richard
Publication year - 2005
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200500181
Subject(s) - tetrahedron , carbodiimide , octahedron , crystallography , chemistry , solid state , crystal structure , metal , materials science , polymer chemistry , organic chemistry
Two solid‐state carbodiimide compounds, LiM 2 (NCN)Br 3 (M = Sr, Eu), with characteristic empty tetrahedral M 4 entities have been synthesized using a flux route, and their structures were determined by single‐crystal X‐ray diffraction. The new phases LiSr 2 (NCN)Br 3 and LiEu 2 (NCN)Br 3 are isotypical with the corresponding iodides and crystallize in the cubic system (( $Fd{\bar 3}m$ , Z = 16) but with smaller unit cells ( a = 14.641(1) Å for LiSr 2 (NCN)Br 3 and 14.572(1) Å for LiEu 2 (NCN)Br 3 ). The extended structures comprise two interpenetrating three‐dimensional networks: the first one is built from isolated M 4 tetrahedra capped by NCN 2− anions on their triangular faces while the second is made from vertex‐sharing LiBr 6 octahedra. The linear NCN 2− anions exhibit the symmetrical carbodiimide shape and serve as linkers between the tetrahedral entities.