The first recorded occurrence of a cenosite sample in Italy is that from Baveno, Novara. The space group is Pmnb and the cell parameters are: a = 13.011(1); b -14.310(1); c = 6.757(1)À; Z = 4. The crystal structure was refined up to an R factor of 0.022 for 1580 reflections, the latter being measured on an automatic single-crystal X-ray diffractometer. In connection with the methods used for chemical analysis, the following formula was found: Ca2(Yi.53REEo.47) [(SÌ3.87Alo.i3)Oi2]C03H20 within the rare-earths Dy > Yb > Er > Gd. In the crystal structure, the Ca and (Y, REE) polyhedra form large, alternating sheets along the b direction. The connection by shared edges and corners of the polyhedra, form large “hexagonal” holes in which the SÌ4O12 rings and CO3 groups are accommodated in the (001) plane across the (010) sheets
Cenosite(Y) from Baveno,Novara (Italy): crystal structure
ODDONE, MASSIMO
1989-01-01
Abstract
The first recorded occurrence of a cenosite sample in Italy is that from Baveno, Novara. The space group is Pmnb and the cell parameters are: a = 13.011(1); b -14.310(1); c = 6.757(1)À; Z = 4. The crystal structure was refined up to an R factor of 0.022 for 1580 reflections, the latter being measured on an automatic single-crystal X-ray diffractometer. In connection with the methods used for chemical analysis, the following formula was found: Ca2(Yi.53REEo.47) [(SÌ3.87Alo.i3)Oi2]C03H20 within the rare-earths Dy > Yb > Er > Gd. In the crystal structure, the Ca and (Y, REE) polyhedra form large, alternating sheets along the b direction. The connection by shared edges and corners of the polyhedra, form large “hexagonal” holes in which the SÌ4O12 rings and CO3 groups are accommodated in the (001) plane across the (010) sheetsI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
