Ln2Al3Si2 (Ln = Ho, Er, Tm): New silicides from molten aluminum - Determination of the Al/Si distribution with neutron crystallography and metamagnetic transitions

: Highly metallic compounds with a quasi-one-dimensional structure, the new ternary compounds Ln2 Al3 Si2 (Ln=Ho, Er, Tm) are synthesized in molten aluminum from lanthanoid and silicon as reagents. Their structures show a formally [Al3 Si2 ]6- framework that contains infinite Al zigzag chains and Si-Si dimers and accommodates rows of Ln3+ ions in parallel tunnels. The compounds exhibit metamagnetic transitions at high magnetic fields.