...B. Winkler; V. Milman; C. J. Pickard Abstract We have studied the structures of Al/Si disordered leucite and bicchulite with a quantum mechanical version of the virtual crystal approximation, VCA. In leucite, the average tetrahedron has a composition of (AlSi 2 )O 4 , while bicchulite represents...

...A. K. Gupta; N. D. Chatterjee Abstract Single-phase bicchulite has been synthesized and its composition established as 2CaO·Al 2 O 3 ·SiO 2 ·H 2 O. Bicchulite crystallizes in space group I 4 3 m , with a = 8.825 ± 0.001 A. Seven reversal brackets have been obtained experimentally...

...Fig. 13 Spurrite crystals (Spu; highly birefringent) associated with calcite (Cal) and bicchulite (Bch, an isotropic mineral). a. Plane-polarized light; b. crossed nicols. Width of field of view: 1.65 cm. ...

... in hydrothermal fluids containing less than 0.7 mole percent CO 2 and decomposes to calcite and quartz under higher CO 2 pressures. Although the stability relations of hydrogrossular and bicchulite have not yet been studied in fluids containing carbon dioxide, the synthesis results and the texture of skarn seem...

... consist of anion-centered cation tetrahedra, resembling small pieces of the CdS structure type. In materials like bicchulite, |Ca 8 (OH) 8 |[Al 8 Si 4 O 24 ]- SOD (Henmi et al. 1974; Sahl and Chatterjee 1977 ; Gupta and Chatterjee 1978 ; Sahl 1980 ) or |REE 4 (Pb 4 O 4 ) 2 |[Al 12 O 24 ]- SOD...

... to I 4̄ as in the case of tugtupite ( DanØ, 1965 ; Hassan & Grundy, 1991a ). Each unit cell contains two sodalite cages and, with the sole exception of bicchulite ( Sahl, 1980 ; Dann et al. , 1996 ), each cage contains up to four extraframework M cations and up to one X anion or anionic group...

...TABLE 6. SELECTED COMPOSITIONS OF MELILITE AND “BICCHULITE” FROM SKARNS AT CORNET HILL AND UPPER CERBOAIA VALLEY, ROMANIA ...

... of several new minerals: bicchulite ( Henmi et al . 1973 ), clinotobermorite ( Henmi & Kusachi 1992 ), fukalite ( Henmi et al . 1977 ), kusachiite ( Henmi 1995 ), morimotoite ( Henmi et al . 1995 ), oyelite ( Kusachi et al . 1980 ), parasibirskite ( Kusachi et al . 1998 ), and takedaite ( Kusachi...

... structures for space group $I{\overline 4} 3m$ . A mineralogical example of the SOD framework within this space group is afforded by the phase bicchulite (Ca 8 Al 8 Si 4 O 24 (OH) 8 ) (Sahl, 1980 ). The symmetry lowering in space group $P{\overline 4} 3n$ from space group $I{\overline...

... cristobalite structure type); there are numerous aluminate sodalities exemplified in the mineral world by bicchulite Ca 2 [Al 2 SiO 6 ](OH) 2 ( Sahl 1980 ); mayenite Ca 12 Al 14 O 33 ( Büssem and Eitel 1936 ) or its Cl-bearing natural variety ( Galuskin et al. 2012 ) have a cubic tetrahedral framework...

... □ □ • thaumasite ⋄ ⋄ ⋄ clinochlore ♦ ⋄ ⋄ chrysotile ♦ ⋄ ⋄ hibschite • • • kamaishilite □ ? □ bicchulite □ ? ? xonotlite ⋄ • ♦ thomsonite • • • gismondine □ □ • mountainite □ □ ? foshagite □ □ ? plombièrite ⋄ ◘ ♦ tobermorite ⋄ ⋄ ♦...

....1959.112.1-6.60 . Dann , S.E. , Mead , P.J. , and Weller , M.T. ( 1996 ) Löwenstein’s rule extended to an aluminium rich framework. The structure of bicchulite, Ca 8 (Al 2 SiO 6 ) 4 (OH) 8 , by MASNMR and neutron diffraction . Inorganic Chemistry , 35 , 1427 – 1428 , https://doi.org...

... (brittle mica) within a bicchulite, Ca 2 (Al 2 SiO 6 )(OH) 2 (sodalite-group mineral), vesuvianite skarn. In addition to these scarce natural occurrences of dellaite, the synthetic analogue has important bearing in the field of cement research: α-Ca 2 [SiO 3 (OH)](OH) (no mineral analogue...

.... The mineral occurs interstitially, and as a veinlet (up to 2 mm wide), forming aggregates of short, prismatic to irregular-shaped crystals associated with bicchulite, vesuvianite, calcite, clintonite, magnetite, and sphalerite. Interstitial dellate is poikiolitic, with inclusions of vesuvianite. Optically...

... )(OH) 2 O 8 H 2 SiAl 2 Ca 2 Bicchulite Ca 2 (Al 2 SiO 6 )(OH) 2 3 O 8 H 2 SiAl 2 Ca 2 Kamaishilite Ca 2 (Al 2 SiO 6 )(OH) 2 4 O 10 H 4 Si 2 Al 2 Ca Lawsonite CaAl 2 (Si 2 O 7 )(OH) 2 ·H 2 O 5 O 12 H 2 Si 2 Al 4 Ca Margarite CaAl 2 (Al 2 Si 2 O 10 )(OH) 2 6 O 12 H 2 Si 3...

... of Al/Si disorder in leucite and bicchulite . Mineral Mag 65 : 819 – 824 Wolverton C , Ozolins V , Zunger A ( 2000 ) Short-range-order types in binary alloys: a reflection of coherent phase stability . J Phys Condens Matter 12 : 2749 – 2768 Wyckoff RWG ( 1963...