SYNTHESIS AND CRYSTAL-STRUCTURE OF SR2ZN( OH)(6) AND BA2ZN(OH)(6)

Crystallization from supersaturated sodium hydroxozincate solutions by adding solutions of alkali earth metal hydroxides yields crystals of Sr2Zn(OH)(6) and Ba2Zn(OH)(6). The X-ray structure determination on th ese crystals was successful including all hydrogen positions: Sr2Zn(OH )(6): P2(1)/n, Z = 2, a = 5.794(1)Angstrom, b = 6.160(1)Angstrom, c = 8.141(1) Angstrom, beta = 91.23(1)degrees, N(F-0(2) greater than or eq ual to 2 sigma F-0(2)) = 1127, N(Var.) = 53, R-1/wR(2) = 0.047/0.081 B a2Zn(OH)(6): P2(1)/n, Z=2, a = 6.043(1)Angstrom, b = 6.336(1)Angstrom, c = 8.451(2) Angstrom, beta = 91.23(2)degrees, N(F-0)(2) greater than or equal to 2 sigma, F-0(2)) = 1669, N(Var.)= 54, R-1/wR(2) = 0.029/0 .067. Sr2Zn(OH)(6) and Ba2Zn(OH)(6) crystallize isotypic in a distorte d Li2O structure type. Si2+ resp. Ba2+ form a cubic primitive arrangem ent. Distorted octahedra of OH-around Zn2+ fill therein alternating cu bic gaps in an ordered way.