Can I read The crystal structure of piergorite-(Ce), Ca8Ce2(Al0.5 Fe0.53+) 1( ,Li,Be)2Si6B8O36(OH,F)2: A new borosilicate from Vetralla, Italy, with a modified hellandite-type chain on EtoBox?

The crystal structure of piergorite-(Ce), Ca8Ce2(Al0.5 Fe0.53+) 1( ,Li,Be)2Si6B8O36(OH,F)2: A new borosilicate from Vetralla, Italy, with a modified hellandite-type chain by M. Boiocchi is a Earth and Planetary Sciences article available to read on EtoBox.

What is The crystal structure of piergorite-(Ce), Ca8Ce2(Al0.5 Fe0.53+) 1( ,Li,Be)2Si6B8O36(OH,F)2: A new borosilicate from Vetralla, Italy, with a modified hellandite-type chain about?

Piergorite-(Ce) is a new mineral found at Tre Croci, Vetralla, Italy with simpliÞ ed formula Ca 8 Ce 2 (Al 0.5 Fe 3+ 0.5 ) Σ1 (■ ■,Li,Be) 2 Si 6 B 8 O 36 (OH,F) 2 . It occurs as strong intergrowths of small crystals, colorless to pale yellow, associated with sanidine, mica, magnetite, rutile, titanite, and other Th-U-REE bearing minerals, in miarolitic cavities of a syenitic ejectum. Piergorite-(Ce) is biaxial negative, n α = 1.717 ( 1), n β = 1.728 (1), and n γ = 1.735 (1), 2V meas = 68(2)°, X = b, and Z ^ c = 7(1)°. Crystals show tabular habit and a very good {010} cleavage; twinning along the (301 -) plane produces "L" forms. The three strongest lines in the simulated powder diffraction pattern (d obs , I, hkl) are: 2.65 Å, 100.0, (213, 4 -13); 1.91 Å, 48.3, (223, 4 -23, 821); 2.90 Å, 44.9, (6 -03, 6 -12). The structure was solved by Patterson synthesis from X-ray diffraction data [monoclinic, space group P2/a, a = 28.097(3) Å, b = 4.777(1) Å, c = 10.236(2) Å, β = 96.81(1)°, V = 1364.2(7) Å 3 , Z = 2] and was reÞ ned to a Þ nal R obs = 0.059 for 6480 Fo with I o > 3σ(I o ). The structure shows similarities with the hellandite group because Si and B tetrahedra form chains along c

Who reads The crystal structure of piergorite-(Ce), Ca8Ce2(Al0.5 Fe0.53+) 1( ,Li,Be)2Si6B8O36(OH,F)2: A new borosilicate from Vetralla, Italy, with a modified hellandite-type chain?

Author

M. Boiocchi

Publisher

Mineralogical Society of America

Published

2006

Language

EN

Field

Earth and Planetary Sciences (Physical Sciences)