Abstract
Phurcalite has been found filling fractures in the tourmaline-bearing granitic pegmatite of Perus, in the north-west part of Sao Paulo city, Brazil. It forms aggregates of radiating euhedral crystals up to 5 mm in length. The crystals are bright yellow, transparent and display vitreous to adamantine lustre. Its streak is pale yellow. Phurcalite is brittle, with a conchoidal fracture, and non-fluorescent. The crystal structure of phurcalite has been solves by single-crystal x-ray diffraction methods and refined to R = 3.8% using 2065 observed [I > 3{sigma}(I)] reflections. The structure consists of [(U O{sub 2}){sub 3} O{sub 2} (P O{sub 4}){sub 2} {sup 4n-}]{sub n} layers, parallel to (010), connected by Ca{sup 2+} ions and H{sub 2} O. The coordination polyhedra are: for U(1) hexagonal bi pyramid; for U(2) and U(3) pentagonal bi pyramids; for Ca(4) and Ca(5) capped trigonal prism and triangulated dodecahedron, respectively; and for P(6) and P(7) tetrahedra. As a consequence of this work, the molecular formula of phurcalite previously reported as Ca{sub 2} (U O{sub 2}){sub 3} (P O{sub 4}){sub 2} (OH){sub 4}.4 H{sub 2} O must be changed to Ca{sub 2} (U O{sub 2}){sub 3} O{sub 2} (P O{sub 4}){sub 2}.7 H{sub 2} O. Other secondary
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Citation Formats
Atencio, D.
Phurcalite and others secondary uranium minerals from Perus, Sao Paulo, Brazil; Furcalita e outros minerais uraniferos secundarios de Perus, Sao Paulo.
Brazil: N. p.,
1991.
Web.
Atencio, D.
Phurcalite and others secondary uranium minerals from Perus, Sao Paulo, Brazil; Furcalita e outros minerais uraniferos secundarios de Perus, Sao Paulo.
Brazil.
Atencio, D.
1991.
"Phurcalite and others secondary uranium minerals from Perus, Sao Paulo, Brazil; Furcalita e outros minerais uraniferos secundarios de Perus, Sao Paulo."
Brazil.
@misc{etde_10157114,
title = {Phurcalite and others secondary uranium minerals from Perus, Sao Paulo, Brazil; Furcalita e outros minerais uraniferos secundarios de Perus, Sao Paulo}
author = {Atencio, D}
abstractNote = {Phurcalite has been found filling fractures in the tourmaline-bearing granitic pegmatite of Perus, in the north-west part of Sao Paulo city, Brazil. It forms aggregates of radiating euhedral crystals up to 5 mm in length. The crystals are bright yellow, transparent and display vitreous to adamantine lustre. Its streak is pale yellow. Phurcalite is brittle, with a conchoidal fracture, and non-fluorescent. The crystal structure of phurcalite has been solves by single-crystal x-ray diffraction methods and refined to R = 3.8% using 2065 observed [I > 3{sigma}(I)] reflections. The structure consists of [(U O{sub 2}){sub 3} O{sub 2} (P O{sub 4}){sub 2} {sup 4n-}]{sub n} layers, parallel to (010), connected by Ca{sup 2+} ions and H{sub 2} O. The coordination polyhedra are: for U(1) hexagonal bi pyramid; for U(2) and U(3) pentagonal bi pyramids; for Ca(4) and Ca(5) capped trigonal prism and triangulated dodecahedron, respectively; and for P(6) and P(7) tetrahedra. As a consequence of this work, the molecular formula of phurcalite previously reported as Ca{sub 2} (U O{sub 2}){sub 3} (P O{sub 4}){sub 2} (OH){sub 4}.4 H{sub 2} O must be changed to Ca{sub 2} (U O{sub 2}){sub 3} O{sub 2} (P O{sub 4}){sub 2}.7 H{sub 2} O. Other secondary uranium minerals associated with Perus phurcalite are autunite, torbernite, meta-autunite, meta-torbernite, chernikovite, meta-uranocircite I, phosphuranylite, uranophane-alpha, uranophane-beta, haiweeite, barian week site and perhaps also bassetite, meta-tyuyamunite and meta-haiweeite. Opal, tridymite, cristobalite, secondary quartz, saponite and rhodochrosite occur associated to the uranium minerals. (author).}
place = {Brazil}
year = {1991}
month = {Dec}
}
title = {Phurcalite and others secondary uranium minerals from Perus, Sao Paulo, Brazil; Furcalita e outros minerais uraniferos secundarios de Perus, Sao Paulo}
author = {Atencio, D}
abstractNote = {Phurcalite has been found filling fractures in the tourmaline-bearing granitic pegmatite of Perus, in the north-west part of Sao Paulo city, Brazil. It forms aggregates of radiating euhedral crystals up to 5 mm in length. The crystals are bright yellow, transparent and display vitreous to adamantine lustre. Its streak is pale yellow. Phurcalite is brittle, with a conchoidal fracture, and non-fluorescent. The crystal structure of phurcalite has been solves by single-crystal x-ray diffraction methods and refined to R = 3.8% using 2065 observed [I > 3{sigma}(I)] reflections. The structure consists of [(U O{sub 2}){sub 3} O{sub 2} (P O{sub 4}){sub 2} {sup 4n-}]{sub n} layers, parallel to (010), connected by Ca{sup 2+} ions and H{sub 2} O. The coordination polyhedra are: for U(1) hexagonal bi pyramid; for U(2) and U(3) pentagonal bi pyramids; for Ca(4) and Ca(5) capped trigonal prism and triangulated dodecahedron, respectively; and for P(6) and P(7) tetrahedra. As a consequence of this work, the molecular formula of phurcalite previously reported as Ca{sub 2} (U O{sub 2}){sub 3} (P O{sub 4}){sub 2} (OH){sub 4}.4 H{sub 2} O must be changed to Ca{sub 2} (U O{sub 2}){sub 3} O{sub 2} (P O{sub 4}){sub 2}.7 H{sub 2} O. Other secondary uranium minerals associated with Perus phurcalite are autunite, torbernite, meta-autunite, meta-torbernite, chernikovite, meta-uranocircite I, phosphuranylite, uranophane-alpha, uranophane-beta, haiweeite, barian week site and perhaps also bassetite, meta-tyuyamunite and meta-haiweeite. Opal, tridymite, cristobalite, secondary quartz, saponite and rhodochrosite occur associated to the uranium minerals. (author).}
place = {Brazil}
year = {1991}
month = {Dec}
}