Synthesis and crystal structure of Ca₂Ag^1.83Al _0-67Ge_1-50 - A solid solution with the NbCoB-type structure

The crystal structure of the new phase, Ca₂Ag _1.83Al_0.67Ge_1.50(1) (1) was determined by single-crystal X-ray diffraction, after the compound was obtained by high temperature synthesis technique. 1 crystallizes with the NbCoB type structure in the orthorhombic space group Pmmn (no. 59) with unit cell parameters: a = 20.505(1) Â, b = 4.3807(2) Å c = 7.2211(3) Å, V= 648.65 ų (Z = 5). The structure of the title compound represent a rare intergrowth of the well known KHg₂ (or CeCu₂) and Fe₂P type structures.