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The crystal structure of Hiortdahlite II

Research paper by S. Merlino, N. Perchiazzi

Indexed on: 01 Aug '87Published on: 01 Aug '87Published in: Mineralogy and Petrology



Abstract

The crystal structure of Hiortdahlite II [triclinic P1,a = 11.012(6),b = 10.342(3),c = 7.359 (3) Å,a = 89.92(2)°, β = 109.21(5)°,y = 90.06(3)°], was determined and refined using 1793 reflections toR1 = 0.069 and R2 = 0.066. The results of the structural study indicated that hiortdahlite II presents the modules which characterize the whole family of minerals related to cuspidine and låvenite, namely “octahedral walls”, four columns large and running alongc, and Si2O7 groups. In hiortdahlite II the modules are connected according to the same topology realized in låvenite. The peculiar octahedral cations distribution, which is determined and discussed in this work, is responsible for the descent in symmetry to P1.[▭