Abstract: A new family of rare earth-rhodium-tin intermetallic compounds, with the representative formula (RE)Rh.sub.x Sn.sub.y, has been synthesized in single crystal form. The compounds containing the heavier rare earths are superconducting and those with the lighter rare earths are generally magnetic. The compound ErRh.sub.1.1 Sn.sub.3.6 exhibits reentrant superconductivity with T.sub.c =0.97 K and T.sub.m =0.57 K as determined from ac magnetic susceptibility measurements. The synthesis and X-ray characterization of the series are described and the results of electrical resistivity, upper critical magnetic field, magnetic susceptibility, specific heat and neutron scattering measurements on the Er compound are given.

Abstract: Disclosed is an electro-optical device in which color changes are electrically induced in an electrochromic material which is a single or polycrystalline niobium tungstate represented approximately by the formula W.sub.9 Nb.sub.8 O.sub.47. The device comprises an ion source and a source of an electrical field which may be reversible so as to produce coloring and bleaching of the electrochromic material. Due to high corrosion resistance of such material, the ion source may conveniently be a hydrous electrolyte.