S. Busche et K. Bluhm, SYNTHESIS AND CRYSTAL-STRUCTURE OF ZINC B ORATE OXIDES CONTAINING ISOLATED TRIGONAL PLANAR BO3 UNITS - ZN5MN(BO3)(2)O-4 AND ZNFE(BO3)O, Zeitschrift fur Naturforschung. B, A journal of chemical sciences, 50(10), 1995, pp. 1450-1454
Single crystals of the new compounds Zn5Mn(BO3)(2)O-4 (A) and ZnFe(BO3
)O (B) were prepared by using a B2O3 flux technique. Zn5Mn(BO3)(2)O-4
is isostructural with Ni5Ti(BO3)(2)O-4 and ZnFe(BO3)O is isotypic with
the mineral warwickite. X-ray investigations on single crystals led t
o (A) space group D-2h(9)-Pbam, a = 926.41(10), b = 1236.67(8), c = 30
4.55(3) pm, Z = 2, and (B) space group D-2h(16)-Pnma, a = 924.62(4), b
= 314.1(10), c = 935.3(2) pm, Z = 4. The structure of Zn5Mn(BO3)(2)O-
4 (A) contains four octahedrally coordinated metal sites, one of these
statistically occupied by Zn2+ and Mn4+. In the structure of ZnFe(BO3
)O the ions Zn2+ and Fe3+ occupy statistically both distorted octahedr
al sites. Both structures contain isolated BO3 units and oxygen that i
s not coordinated to boron.