DONOR LAYER-ACCEPTOR CHAIN FORMATION IN THE LANIGE2 STRUCTURE - A CRYSTALLOGRAPHIC AND COMPUTATIONAL STUDY

Synthesis, and single-crystal X-ray diffraction and computational stud ies were carried out for the title compound. LaNiGe2 crystallizes in t he orthorhombic lattice Cmcm (a = 4.3040(6) Angstrom, b = 16.892(10) A ngstrom, c = 4.2367(5) Angstrom, Z = 4). It consists of a Ni-capped Ge square lattice and Ge zigzag chains. A unique structural feature is t he formation of the square lattice by the more electronegative Ge inst ead of by Ni atoms as in several other phases such as La3Ni4Ge4. Compu tational analysis indicates that the Ge square lattice acts as an elec tron donor while the Ge zigzag chain acts as electron acceptor. A dono r-acceptor interaction similar to that in the CaBe2Ge2 phase stabilize s the Ge square lattice.