The Experts below are selected from a list of 138 Experts worldwide ranked by ideXlab platform
George R Rossman - One of the best experts on this subject based on the ideXlab platform.
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Dielectric constants of diaspore and B-, Be-, and P-containing minerals, the polarizabilities of B_2O_3 and P_2O_5, and the oxide additivity rule
American Mineralogist, 1992Co-Authors: R D Shannon, M.a. Subramanian, Anthony N. Mariano, Thurman E. Gier, George R RossmanAbstract:The 1-MHz dielectric constants and loss factors of the minerals diaspore, euclase, hamberyite, sinhalite, danburite, datolite, beryllonite, and montebrasite and of the synthetic oxides La_(2)Be_(2)O_5, AlP_(3)O_9, and NdP_(5)O_14, were determined. The dielectric polarizabilities of B_(2)O_3, and P_(2)O_5, derived from the dielectric constants of these compounds are 6.15 and 12.44 A^3, respectively. The dielectric constants of the above minerals and oxides, along with the dielectric polarizabilities of Li_(2)O, Na_(2)O, BeO, MgO, CaO, Al_(2)O_3, Nd_(2_O_3, La_(2)O_3, SiO_2, diaspore, and the derived values of the polarizabilities of B_(2)O_3, and P_(2)O_5, were used to calculate dielectric polarizabilities from the Clausius-Mosotti equation and to test the oxide additivity rule. The oxide additivity rule is valid to ±0.5% for all except beryllonite. These compounds with deviations from additivity of 0.5-1.5%, along with previously studied aluminate and gallate garnets, Chrysoberyl, spinel, phenacite, zircon, and olivinetype silicates, form a class of well-behaved oxides that can be used as a basis for comparison of compounds that show larger deviations (>5%) caused by ionic or electronic conductivity, the presence of H_(2)O or CO_2, or structural peculiarities.
R D Shannon - One of the best experts on this subject based on the ideXlab platform.
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Dielectric constants of diaspore and B-, Be-, and P-containing minerals, the polarizabilities of B_2O_3 and P_2O_5, and the oxide additivity rule
American Mineralogist, 1992Co-Authors: R D Shannon, M.a. Subramanian, Anthony N. Mariano, Thurman E. Gier, George R RossmanAbstract:The 1-MHz dielectric constants and loss factors of the minerals diaspore, euclase, hamberyite, sinhalite, danburite, datolite, beryllonite, and montebrasite and of the synthetic oxides La_(2)Be_(2)O_5, AlP_(3)O_9, and NdP_(5)O_14, were determined. The dielectric polarizabilities of B_(2)O_3, and P_(2)O_5, derived from the dielectric constants of these compounds are 6.15 and 12.44 A^3, respectively. The dielectric constants of the above minerals and oxides, along with the dielectric polarizabilities of Li_(2)O, Na_(2)O, BeO, MgO, CaO, Al_(2)O_3, Nd_(2_O_3, La_(2)O_3, SiO_2, diaspore, and the derived values of the polarizabilities of B_(2)O_3, and P_(2)O_5, were used to calculate dielectric polarizabilities from the Clausius-Mosotti equation and to test the oxide additivity rule. The oxide additivity rule is valid to ±0.5% for all except beryllonite. These compounds with deviations from additivity of 0.5-1.5%, along with previously studied aluminate and gallate garnets, Chrysoberyl, spinel, phenacite, zircon, and olivinetype silicates, form a class of well-behaved oxides that can be used as a basis for comparison of compounds that show larger deviations (>5%) caused by ionic or electronic conductivity, the presence of H_(2)O or CO_2, or structural peculiarities.
Ron Chapman - One of the best experts on this subject based on the ideXlab platform.
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EFFECTS OF SILLIMANITE-GRADE METAMORPHISM AND SHEARING ON Nb_TA OXIDE MINERALS IN GRANITIC PEGMATITES: MAR$IKOV. NORTHERN MORAVIA, CZECHOSLOVAKIA
2015Co-Authors: Milan Novak, Ron ChapmanAbstract:The (Be,Nb,Ta)-bearing albite-muscovite pegmarites at Marsftov, in the Hrubf Jesenik Mountains pegmatite field of northern Moravia, Czechoslovakia, *ete iubjected to a two-stage, sillimanite-grade, regional metamorphism tlat reached about 600oC and 4-6 kbar, P(rotal)>> P(fluid). The first stage generated Chrysoberyl at the expense of beryl, under relatively staiic conditions (pegmatite I), whereas extensive shearing during a second stage produced a second generation of Chrysoberyl, abundant sillimanite and a foliation (pegrnatite III). The primary.assemblage of the M-Ta oxide minerals consisted of manganocolumbite-manganotantalite displaying oscillatory zoning in terms of M and Ta, replaced by fersmite and microlite (rarely pyrochlore). The columbite-tantalite was frst recrystallized into,,bird'j-eye " oscillitory-zoned textures or heterogeneous granular aggxegates. The original range of,Tal(Ta + Nb) values was commonly reduced, although locally expanded by contribution of additional Nb or Ta from incipient breakdown of fersmite or microlite, respectively. Mn/(Mn + Fe) largely decreased, by as much as 0.40, by introduction of Fe from the host hornblende gneisi; Mg and Ti also were enriched. During the second metamorphic stage ' the Tal(Ta + |r{!) value of columbite-tintalite wis locally further homogenized, but Mn/(Mn + Fe) did not change. Fersmite and microlite were almost completely obliterated. Significant ordering of the originally intermediate structural slate of columbite-tantalite was piomoted during metamorphic recrystallization. This study documents extensiv
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effects of sillimanite grade metamorphism and shearing on nb ta oxide minerals in granitic pegmatites marsikov northern moravia czechoslovakia
Canadian Mineralogist, 1992Co-Authors: Petr Cerny, Milan Novak, Ron ChapmanAbstract:The (Be,Nb,Ta)-bearing albite-muscovite pegmarites at Marsftov, in the Hrubf Jesenik Mountains pegmatite field of northern Moravia, Czechoslovakia, *ete iubjected to a two-stage, sillimanite-grade, regional metamorphism tlat reached about 600oC and 4-6 kbar, P(rotal) > > P(fluid). The first stage generated Chrysoberyl at the expense of beryl, under relatively staiic conditions (pegmatite I), whereas extensive shearing during a second stage produced a second generation of Chrysoberyl, abundant sillimanite and a foliation (pegrnatite III). The primary.assemblage of the M-Ta oxide minerals consisted of manganocolumbite-manganotantalite displaying oscillatory zoning in terms of M and Ta, replaced by fersmite and microlite (rarely pyrochlore). The columbite-tantalite was frst recrystallized into ,,bird'j-eye" oscillitory-zoned textures or heterogeneous granular aggxegates. The original range of,Tal(Ta + Nb) values was commonly reduced, although locally expanded by contribution of additional Nb or Ta from incipient breakdown of fersmite or microlite, respectively. Mn/(Mn + Fe) largely decreased, by as much as 0.40, by introduction of Fe from the host hornblende gneisi; Mg and Ti also were enriched. During the second metamorphic stage' the Tal(Ta + |r{!) value of columbite-tintalite wis locally further homogenized, but Mn/(Mn + Fe) did not change. Fersmite and microlite were almost completely obliterated. Significant ordering of the originally intermediate structural slate of columbite-tantalite was piomoted during metamorphic recrystallization. This study documents extensive compositional and structural re-equilibration of M-Ta oxide minerals at medium-gxade regional metamorphic conditions. This pattern of behavior contrasts with their virtual inertness in an environment of mylonitization.
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EFFECTS OF SILLIMANITE-GRADE MET AMORPHISM AND SHEARING ON Nb-Ta OXIDE MINERALS IN GRANITIC PEGMATITES: MARS(KOV, NORTHERN MORAVIA, CZECHOSLOVAKIA
1992Co-Authors: Petr C Erny, Ron ChapmanAbstract:ABSTRACT 699 The (Be,Nb,Ta)-bearing albite-muscovite pegmatites at Mar5ikov, in the Hruby Jesenik Mountains pegmatite field of northern Moravia, Czechoslovakia, were subjected to a two-stage, sillimanite-grade, regional metamorphism that reached about 600°C and 4-6 kbar, P(total) > > P(fluid). The first stage generated Chrysoberyl at the expense of beryl, under relatively static conditions (pegmatite 1), whereas extensive shearing during a second stage produced a second generation of Chrysoberyl, abundant sillimanite and a foliation (pegmatite III). The primary assemblage of the Nb-Ta oxide minerals consisted of manganocolumbite-manganotantalite displaying oscillatory zoning in terms of Nb and Ta, replaced by fersmite and rnicrolite (rarely pyrochlore). The columbite-tantalite was first recrystallized into "bird's-eye" oscillatory-zoned textures or heterogeneous granular aggregates. The original range of Ta/(Ta + Nb) values was commonly reduced, although locally expanded by contribution of additional Nb or Ta from incipient breakdown of fersrnite or microlite, respectively. Mn/(Mn +Fe) largely decreased, by as much as 0.40, by introduction of Fe from the host hornblende gneiss; Mg and Ti also were enriched. During the second metamorphic stage, the Ta/(Ta + Nb) value of columbite-tantalite was locally further homogenized, but Mn/(Mn +Fe) did not change. Fersmite and microlite were almost completely obliterated. Significant ordering of the originally intermediate structural state of columbite-tantalite was promoted during metamorphic recrystallization. This study documents extensive compositional and structural re-equilibration of Nb-Ta oxide minerals at medium-grade regional metamorphic conditions. This pattern of behavior contrasts with their virtual inertness in an environment of mylonitization
M.a. Subramanian - One of the best experts on this subject based on the ideXlab platform.
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Dielectric constants of diaspore and B-, Be-, and P-containing minerals, the polarizabilities of B_2O_3 and P_2O_5, and the oxide additivity rule
American Mineralogist, 1992Co-Authors: R D Shannon, M.a. Subramanian, Anthony N. Mariano, Thurman E. Gier, George R RossmanAbstract:The 1-MHz dielectric constants and loss factors of the minerals diaspore, euclase, hamberyite, sinhalite, danburite, datolite, beryllonite, and montebrasite and of the synthetic oxides La_(2)Be_(2)O_5, AlP_(3)O_9, and NdP_(5)O_14, were determined. The dielectric polarizabilities of B_(2)O_3, and P_(2)O_5, derived from the dielectric constants of these compounds are 6.15 and 12.44 A^3, respectively. The dielectric constants of the above minerals and oxides, along with the dielectric polarizabilities of Li_(2)O, Na_(2)O, BeO, MgO, CaO, Al_(2)O_3, Nd_(2_O_3, La_(2)O_3, SiO_2, diaspore, and the derived values of the polarizabilities of B_(2)O_3, and P_(2)O_5, were used to calculate dielectric polarizabilities from the Clausius-Mosotti equation and to test the oxide additivity rule. The oxide additivity rule is valid to ±0.5% for all except beryllonite. These compounds with deviations from additivity of 0.5-1.5%, along with previously studied aluminate and gallate garnets, Chrysoberyl, spinel, phenacite, zircon, and olivinetype silicates, form a class of well-behaved oxides that can be used as a basis for comparison of compounds that show larger deviations (>5%) caused by ionic or electronic conductivity, the presence of H_(2)O or CO_2, or structural peculiarities.
Anthony N. Mariano - One of the best experts on this subject based on the ideXlab platform.
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Dielectric constants of diaspore and B-, Be-, and P-containing minerals, the polarizabilities of B_2O_3 and P_2O_5, and the oxide additivity rule
American Mineralogist, 1992Co-Authors: R D Shannon, M.a. Subramanian, Anthony N. Mariano, Thurman E. Gier, George R RossmanAbstract:The 1-MHz dielectric constants and loss factors of the minerals diaspore, euclase, hamberyite, sinhalite, danburite, datolite, beryllonite, and montebrasite and of the synthetic oxides La_(2)Be_(2)O_5, AlP_(3)O_9, and NdP_(5)O_14, were determined. The dielectric polarizabilities of B_(2)O_3, and P_(2)O_5, derived from the dielectric constants of these compounds are 6.15 and 12.44 A^3, respectively. The dielectric constants of the above minerals and oxides, along with the dielectric polarizabilities of Li_(2)O, Na_(2)O, BeO, MgO, CaO, Al_(2)O_3, Nd_(2_O_3, La_(2)O_3, SiO_2, diaspore, and the derived values of the polarizabilities of B_(2)O_3, and P_(2)O_5, were used to calculate dielectric polarizabilities from the Clausius-Mosotti equation and to test the oxide additivity rule. The oxide additivity rule is valid to ±0.5% for all except beryllonite. These compounds with deviations from additivity of 0.5-1.5%, along with previously studied aluminate and gallate garnets, Chrysoberyl, spinel, phenacite, zircon, and olivinetype silicates, form a class of well-behaved oxides that can be used as a basis for comparison of compounds that show larger deviations (>5%) caused by ionic or electronic conductivity, the presence of H_(2)O or CO_2, or structural peculiarities.