Synthesis, crystal structure and some physical properties of RuZn3.

The crystal structure, phase relations and some physical properties of the binary zinc-rich phase RuZn3 are reported. The title compound is accessible via high-temperature reaction from the elements in the appropriate substance amount ratio. Its crystal structure was determined from a Rietveld profile fit to an X-ray diffractogram of pristine RuZn3 and confirmed by single-crystal X-ray structure analysis. The title compound adopts a tetragonal Al3Zr-type structure corresponding to an A2B2 anti-phase domain structure of the cubic AuCu3-type: a=376.82(3) pm, c=1554.78(13) pm, I4/mmm, Z=4, R(F)(all data)=0.0197, 153 unique reflections, 12 variables. The structure is discussed in the light of the Hume-Rothery concept. RuZn3 melts at 1373(2) K, is a moderate metallic conductor (rho(293 K)=6.2 mOmega cm) and exhibits basically temperature-independent paramagnetic properties. It coexists with Ru1-xZnx and RuZn6.