Centrosymmetric Modular Structure of a Labyrinthite Analogue

摘要

Among minerals of the eudialyte group,minerals with a doubled c lattice parameter(60-61 A)and symmetry R3m or with the more rare space groups R3(labyrinthite)or R3 m(alluaivite)are of particular interest.Such structures are commonly considered as modular because they are composed of fragments of different minerals(in the case under consideration,of minerals belonging to the same group).In the present study,we established the crystal structure of a new representative of the eudialyte group with a doubled unit cell and the centrosymmetric space group R3 m.