Kozulite, an Mn-rich alkali amphibole.

ABSTRACT: The crystal structure of kôzulite, an Mn-rich alkali amphibole with the ideal formula NaNa(2)[Mn(4) (2+)(Fe(3+),Al)]Si(8)O(22)(OH)(2), tris-odium tetra-manganese iron/aluminium octa-silicate dihydroxide, was refined from a natural specimen with composition (K(0.20)Na(0.80))(Na(1.60)Ca(0.18)Mn(2+) (0.22))(Mn(2+) (2.14)Mn(3+) (0.25)Mg(2.20)Fe(3+) (0.27)Al(0.14))(Si(7.92)Al(0.06)Ti(0.02))O(22)[(OH)(1.86)F(0.14)]. The site occupancies determined from the refinements are M1 = 0.453 (1) Mn + 0.547 (1) Mg, M2 = 0.766 (1) Mn + 0.234 (1) Mg, and M3 = 0.257 (1) Mn + 0.743 (1) Mg, where Mn and Mg represent (Mn+Fe) and (Mg+Al), respectively. The average M-O bond lengths are 2.064 (1), 2.139 (1), and 2.060 (1) Å for the M1, M2, and M3 sites, respectively, indicating the preference of large Mn(2+) for t

SUBMITTER: Barkley MC 

PROVIDER: S-EPMC3011386 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature