The crystal structure of astrophyllite K2Na(Fe, Mn, Mg, □)7[Ti2(Si 4O12)2|O3](OH, F)4 has been refined. The dimensions of the triclinic unit cell are: a = 0.5359(2) nm, b = 1.1614(4) nm, c = 1.1861(4) nm, a = 113.16(...The crystal structure of astrophyllite K2Na(Fe, Mn, Mg, □)7[Ti2(Si 4O12)2|O3](OH, F)4 has been refined. The dimensions of the triclinic unit cell are: a = 0.5359(2) nm, b = 1.1614(4) nm, c = 1.1861(4) nm, a = 113.16(2)°, b = 103.04(2) °, g = 94.56(2) °, V = 0.6495(5) nm3, Z = 1, space group P1, R=0.057 for 5308 reflections |Fo|>3s|Fo|. According to structural and compositional differences the monoclinic astrophyllite K2NaNa(Fe, Mn)4Mg2Ti2[Si4O12]2(OH)4(OH, F)2 and astrophyllite should be considered as two different mineral species. Astrophyllite, monoclinic astrophyllite, bafertisite and lamprophyllite contain heteropolyhedral sheets which topologically are related with Si, O sheets of mica where one or several SiO4 tetrahedra are replaced by TiOn polyhedra. Therefore this heterophyllotitanosilicate series represents a kind of functional substitution in inorganic crystals.展开更多
基金in part by The National Natural Science Foundation of China (Grant No. 49872019) and Russian Scientific Foundation (Grant No. 99-05-35019).
文摘The crystal structure of astrophyllite K2Na(Fe, Mn, Mg, □)7[Ti2(Si 4O12)2|O3](OH, F)4 has been refined. The dimensions of the triclinic unit cell are: a = 0.5359(2) nm, b = 1.1614(4) nm, c = 1.1861(4) nm, a = 113.16(2)°, b = 103.04(2) °, g = 94.56(2) °, V = 0.6495(5) nm3, Z = 1, space group P1, R=0.057 for 5308 reflections |Fo|>3s|Fo|. According to structural and compositional differences the monoclinic astrophyllite K2NaNa(Fe, Mn)4Mg2Ti2[Si4O12]2(OH)4(OH, F)2 and astrophyllite should be considered as two different mineral species. Astrophyllite, monoclinic astrophyllite, bafertisite and lamprophyllite contain heteropolyhedral sheets which topologically are related with Si, O sheets of mica where one or several SiO4 tetrahedra are replaced by TiOn polyhedra. Therefore this heterophyllotitanosilicate series represents a kind of functional substitution in inorganic crystals.
