Direct and indirect preparation of layered quaternary manganese tellurides; AMn xM yTe 2 (A=Li, Na; M=Cu, Ag; x+ y≤2)

Abstract

A series of layered quaternary tellurides with AMn x M y Te 2 (A=Li, Na; M=Cu, Ag; x+ y≤2) compositions were prepared in two different ways; direct synthesis from elemental starting materials and reaction of coinage metals (Cu or Ag) with ternary tellurides, AMnTe 2 (A=Li, Na) with partially empty tetrahedral sites. Products were characterized by single crystal and powder X-ray diffraction, atomic absorption (AA) measurements, and wavelength dispersive spectrometry (WDS). These compounds adopt the CaAl 2Si 2 structure type (space group Pm 3 1 , No. 164), in which Te atoms are arrayed by hexagonal closed packing with random distribution of Mn and M (Cu or Ag) atoms in the tetrahedral sites. Alkali metals reside in octahedral sites between two layers to complete the structure. Resistivity measurements showed that these compounds are either insulators or semiconductors.