STRUCTURE OF CRYSTALLINE (C(5)ME(5))REO3 AND IMPLIED NONEXISTENCE OF (C(5)ME(5))TC2O3

The crystal structure of (C(5)Me(5))ReO3 has been solved and refined, despite the fact that the crystals exhibit both twinning and disorder phenomena. The-crystals are monoclinic pseudomerohedral twins, made possible because the unique angle congruent to 90 degrees in space group P2(1)/m (c-axis unique). The metal atom is disordered over two positions, and the crystals are twinned about the [100] plane. The unit cell has the dimensions a = 5.9330(5) Angstrom, b = 8.672(1) Angstrom,c = 10.590(2) Angstrom, gamma = 90.01(1)degrees, V = 544.9(1) Angstrom(3), and Z = 2. The individual molecules of (C-5-Me(5))ReO3 are effectively identical to those previously reported for (C(5)Me(4)Et)ReO3 except for the replacement of one Me by Et. All hydrogen atoms were located, and those not disordered about the mirror plane were refined independently. The final residuals are R1 (on F-0) = 0.0257 and wR2 (on F-0(2)) = 0.0616, using all data. It is clear that the previously reported compound (C(5)Me(5))Tc2O3 does not exist. The reported structure, which contains several patently unbelievable features, is shown to be an artifact. It will also be shown that it is extremely unlikely that (C(5)Me(5))TcO3 exists either.