SYNTHESES AND CRYSTAL-STRUCTURES OF SOME NEW RARE-EARTH BASIC NITRATES .2. [LN(6)O(OH)(8)(H2O)(12)(NO3)(6)](NO3)(2).XH(2)O, LN=SM, DY, ER X(SM)=6, X(DY)=5, X(ER)=4

The title compounds were synthesized and their structures determined. The samarium compound crystallizes with a new structure type: P (1) ov er bar, a=11.595(2), b=11.697(2). c=16.720(3)Angstrom, alpha=91.05(2), beta=90.00(1); gamma=112.97(2)degrees, V=2087.5(6) Angstrom(3) Z=2. T he dysprosium compound is isotypic with the previously reported struct ure of the gadolinium compound: C2/c, a=12.623(3), b=18,798(4), c=17.4 65(4)Angstrom, p=106.70(2)degrees, V=3969.4(16)Angstrom(3), Z=4. The e rbium compound has the same structure as the earlier reported structur e of the ytterbium compound: P (1) over bar, a=10.056(2), b=10.064(2), c=11.397(2)Angstrom, alpha=96.49(1), beta=108.81(1), gamma=110.90(2)d egrees, V=985.5(3) Angstrom(3), Z=1. The structures, which are closely related, are built up of [Ln(6)O(OH)(8)(H2O)(12)(NO3)(6)](2+) cluster s with additional (NO;)L-and H2O groups in between. (C) 1997 Elsevier Science S.A.