An anti CuO2-type metal hydride square net structure in Ln2M2As2H(x) (Ln=La or Sm, M=Ti, V, Cr, or Mn).
Using a high pressure technique and the strong donating nature of H(-), a new series of tetragonal La2Fe2Se2O3-type layered mixed-anion arsenides, Ln2M2As2H(x), was synthesized (Ln=La or Sm, M=Ti, V, Cr, or Mn; x≈3). In these compounds, an unusual M2H square net, which has anti CuO2 square net structures accompanying two As(3-) ions, is sandwiched by (LaH)2 fluorite layers. Notably, strong metal-metal bonding with a distance of 2.80 Å was confirmed in La2Ti2As2H2.3, which has metallic properties. In fact, these compounds are situated near the boundary between salt-like ionic hydrides and transition-metal hydrides with metallic characters.
Materials Research Center for Element Strategy, Tokyo Institute of Technology, Yokohama 226-8503 (Japan). mizoguchi@lucid.msl.titech.ac.jp.
Hiroshi
H
Mizoguchi
SangWon
S
Park
Haruhiro
H
Hiraka
Kazutaka
K
Ikeda
Toshiya
T
Otomo
Hideo
H
Hosono
high-pressure chemistry; hydrides; metal-metal interactions; mixed anion phases; titanium