  The palladium-iron-arsenides Ca10(Fe1-xPdxAs)10(Pd3As8) were synthesized by
solid state methods and characterized by X-ray powder and single crystal
diffraction. The triclinic crystal structure (space group P-1) is isotypic to
the homologue platinum 1038 type superconductors with alternating FeAs4/4- and
Pd3As8-layers, each separated by layers of calcium atoms. Iron is tetrahedral
and palladium is planar coordinated by four arsenic atoms. As2-dimers (dAs-As =
250 pm) are present in the Pd3As8-layer. Even though each layer itself has a
fourfold rotational symmetry, the shifted layer stacking causes the triclinic
space group. Resistivity measurements of La-doped samples show the onset of
superconductivity at 17 K and zero resistivity below 10 K. The magnetic
shielding fraction is about 20 % at 3.5 K. 57Fe-M\"ossbauer spectra exhibit one
absorption line and show no hint to magnetic ordering. The electronic structure
is very similar to the known iron-arsenides with cylinder-like Fermi surfaces
and partial nesting between hole- and electron-like sheets. Our results show
that superconductivity in the palladium-iron-compounds is present but
complicated by too high substitution of iron by palladium in the active
FeAs-layers. Since the electronic preconditions are satisfied, we expect higher
critical temperatures in Pd1038-compounds with lower or even without Pd-doping
in the FeAs-layer.
