The Yb-Ru-Sn ternary system was investigated and a new material, Yb0.24Sn0.76Ru, with a simple cubic crystal structure, was discovered. Yb0.24Sn0.76Ru has a smaller lattice parameter a = 3.217(4) angstrom, than its isostructural YbRu analogue (a = 3.360 angstrom). Both X-ray diffraction and electron microscopy techniques were used to refine the crystal structure of Yb0.24Sn0.76Ru. It was found that a new compound forms in the CsCl structure, with Ru on the la site and a (Yb,Sn) mixture on site 1b. The XRD Rietveld analysis provides the occupation of Yb equal to 0.24, in agreement with the single crystal nano-electron diffraction refinement, which gives the occupation 0.21. (C) 2010 Elsevier B.V. All rights reserved.