CRYSTAL-STRUCTURE OF SODIUM DICHLOROBIS(ACETYLACETONATO)RHODIATE(III)MONOHYDRATE NA[RH(C5H7O2)(2)CL-2]CENTER-DOT-H2O - PSEUDOPERIODICITY AS THE CONSEQUENCE OF THE PACKING LAW OF COMPLEXES IN CRYSTALS

The crystal structure of Na[Rh(acac)(2)Cl-2]. H2O (acac = C5H(7)O(2)(- )) is determined. The crystals are triclinic, space group P (1) over b ar with unit cell dimensions a = 12.616(2), b = 8.411(4), c = 8.499(4) Angstrom, alpha = 108.37(4), beta = 95.47(4), gamma = 110.45(4)degree s, V = 780.3(6) Angstrom(3), Z = 2, d(calc) = 1.758 g/cm(3), R = 0.046 1. The strong pseudoperiodicity observed experimentally (no reflection s with odd indices h) led to a set of experimental data obtained in th e unit cell that is reduced along the a axis (''Syntex P2(1)'' automat ic diffractometer, lambda MoKalpha, graphite monochromator), 1466 meas ured and 1302 observed I-hkl included in the calculation. This is due to the alternation of the central atoms of octahedral complex anions a t intervals of 1/2a. The Rh-O and Rh-Cl distances are, on the average, 2.001(3) and 2.325(2), respectively. The cis-angles of ClRhO type are close to 90 degrees, and the average value of the ORhO chelate angle is 95.1 degrees (within 3 sigma with sigma congruent to 0.1 degrees). The average interatomic distances and bond angles (according to types) in the acac ligand are as follows: O-C 1.274, (C-C)(ring) 1.397, C-ri ng-C-sub 1.506 Angstrom with sigma not higher than 0.006 Angstrom, RhO C 122.2 degrees, (OCC)(ring) 126.4 degrees, (OCC)(tem) 114.2 degrees, (CCC)(ring) 127.3 degrees, (CC)(ring)C-sub 119.3 degrees (sigma within 0.2-0.6 degrees). The distorted octahedron around the Na ion consists of five O atoms (of the H2O molecule and the neighboring acac ligands , distances within 2.364-2.409 Angstrom) and one Cl ion lying at a dis tance of 2.970 Angstrom. The structure in general is of ribbon type: R h-1,Rh-2 and Na octahedra are linked by a common edge O(2')O(1) and co mmon face O(3)O(4')O(2') into infinite ribbons, which are extended alo ng the [100] axis and which are translationally identical in the [010] and [001] directions. The H2O molecule forms two Cl(1)... H2O ... Cl( 2') hydrogen bonds: 3.116 and 3.179 Angstrom, respectively, which link the Rh octahedra into infinite chains in the [120] direction.