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The phases R3I3Ru (R = La, Pr, Gd, Y, Er) and R3I3Ir (R = Gd, Y) are obtained from the reactions of R, RI3, and Ru or Ir for 3-4 weeks in sealed Ta tubing at 850-975 C, depending on the system. The title phases have been characterized by single-crystal X-ray means at room temperature, with space group P21/m and Z = 2 (Pr3I3Ru, Y3I3Ru, Y3I3Ir, respectively: a = 9.194 (1), 8.7001 (4), 8.6929 (7) ; b = 4.2814 (5), 4.1845 (2), 4.2388 (4) ; c = 12.282 (2), 12.1326 (6), 12.092 (2) ; / = 93.46 (1), 94.769 (5), 94.73 (1); R/Rw = 3.7/3.4, 3.2/5.5, 4.4/4.0%). The first phase contains quasi-infinite double chains of edge-sharing Pr6(Ru) octahedra that are sheathed and interbridged by iodine. An evidently continuous distortion of these chains parallels the a/b axial ratio (in the order listed in the first sentence) such that metal octahedra are no longer obvious in Y3I3Ir; rather chains of trans-edge-sharing square pyramidal Y4Ir units bonded base-to-base are more apt. Increased R-R, R-interstitial, and interstitial-interstitial bonding appears to parallel the degree of distortion. Magnetic data for La3I3Ru and Pr3I3Ru and the results of extended Hiickel band calculations on Pr3I3Ru are reported. Polar covalent Pr-Ru interactions and at least a quasi-closed shell configuration are emphasized by the latter. 1992, American Chemical Society. All rights reserved.
author list (cited authors)
Payne, M. W., Dorhout, P. K., Kim, S. J., Hughbanks, T. R., & Corbett, J. D.