Nepheline Solid Solution in the System NaAISiO4-KAISiO4-SiO2

Hamilton, D. L.; MacKenzie, W. S.

doi:10.1093/petrology/1.1.56

Cited by 60 publications

(31 citation statements)

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“…The most extensive data refer to the system NaA1SiO4-KA1SiO~ (Sahama etal. 1956;Smith and Tuttle 1957;Donnay et al 1959;Hamilton and MacKenzie 1960;Roux 1974;Ferry and Blencoe 1978) and show that the kalsilite cell is found for compositions from 68 to ca 100 mol% KA1SiO4, and nepheline from ca 0 to 69 mol% KA1SiO4, the wide ranges of solid solution becoming smaller for crystals grown at lower temperatures. For ca 70 mol% KAlSiO4, two further structures have recently been resolved, namely tetrakalsilite (Merlino et al 1985) and trikalsilite (Bonaccorsi et al 1988).…”

Section: Introductionmentioning

confidence: 97%

Ion exchange between tectosilicates with the nepheline-kalsilite framework and molten MNO3 or MO (M = Li, Na, K, Ag)

Sobrados

Gregorkiewitz

1993

Phys Chem Minerals

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Abstract. Natural nepheline, a synthetic Na-rich nepheline, and synthetic kalsilite were ion exchanged in molten MNO3 or MC1 (M=Li, Na, K, Ag) at 220-800 ~ C. Crystalline products were characterized by wet chemical and electron microprobe analysis, single crystal and powder X-ray diffraction, and transmission electron microscopy and diffraction. Two new compounds were obtained: Li-exchanged nepheline with a formula near (Li,Ko.3,D)Li~[A13(A1,Si)Si~O16] and a monoclinic unit cell with a=951.0(6) b=976.1(6) c=822.9(5) pm 7= 119.15 ~ and Ag-exchanged nepheline with a formula near (K,Na, D)Ag3[At3(A1,Si)Si40~6] and a hexagonal unit cell with a = 1007.4(8) c = 838.2(1.0) pm. Both compounds apparently retain the framework topology of the starting material. Ion exchange isotherms and structural data show that immiscibility between the end members is a general feature in the systems Na-Li, Na-Ag, and Na-K. For the system Na-K, a stepwise exchange is observed with (K,D)Na3[A13(AI,Si)Si40~6] as an intermediate composition which has the nepheline structure and is miscible with the sodian end member (Na,D)Na3[A13-(A1,Si)Si40~6], but not with the potassian end member (K,D)4[A13(A1,Si)Si4Oa6] which shows the kalsilite structure; there was no indication for the formation of trior tetrakalsilite (K/(K + Na) ~ 0.7) at the temperatures studied (350 and 800 ~ C). The exact amount of vacancies [] on the alkali site depends upon the starting material and was found to be conserved during exchange, with ca 0-0.2 and 0.3-0.4 vacancies per 16 oxygen atoms for the synthetic and natural precursors, respectively. Thermodynamic interpretation of the Na-K exchange isotherms shows, as one important result, that the sodian end member is unstable with respect to the intermediate at K/(K +Na)~ 0.25 by an amount of ca 45 kJ/mol Na in the large cavity at 800 ~ C (52 kJ/mol at 350 ~ C).

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Section: Introductionmentioning

confidence: 97%

Ion exchange between tectosilicates with the nepheline-kalsilite framework and molten MNO3 or MO (M = Li, Na, K, Ag)

Sobrados

Gregorkiewitz

1993

Phys Chem Minerals

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“…Roy (1956) found that coprecipitating gels is an effective method for preparing homogeneous mixtures. Hamilton and Mackenzie (1960) used the technique to prepare homogeneous materials of the required compositions for their system, NaA1Si0 4 -KA1Si0 4 -Si0 2 . Luth and Ingamells ( 1965) used a volumetric combination of carefully standardized aqueous solutions of metal nitrates and hydroxides, and a soda-or ammonia-stabilized silica sol of high purity.…”

Section: Silica Gel Samplesmentioning

confidence: 99%

Reference samples in geology and geochemistry

Flanagan¹

1986

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“…O outro é representado por Na 2 O -Fe 2 O 3 -Al 2 O 3 -SiO 2 , com os membros finais Ne, FeNe e Qz (e.g. Bailey & Schairer, 1963;Bailey & Schairer, 1966;Onuma et al, 1972 de equilíbrio do sistema (Hamilton & MacKenzie, 1960;Hamilton, 1961 Cristais maiores e poiquilíticos também ocorrem. É comum apresentarem um núcleo de arfvedsonita, em clara relação de substituição, neste caso apresenta uma cor mais escura.…”

Section: Estrutura E Substituiçõesunclassified

“…O geotermômetro da nefelina (Hamilton & MacKenzie, 1960;Hamilton, 1961) A presença de albita quase pura (>Ab 95 ) geralmente é interpretada como sendo de reequilíbrio pós magmático, já que sua temperatura de equilíbrio é inferior a 500°C.…”

Section: Temperaturaunclassified

Geologia e Petrologia da suíte alcalina de Bom Repouso, MG

Rosa¹

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Nepheline Solid Solution in the System NaAISiO4-KAISiO4-SiO2

Cited by 60 publications

References 0 publications

Ion exchange between tectosilicates with the nepheline-kalsilite framework and molten MNO3 or MO (M = Li, Na, K, Ag)

Ion exchange between tectosilicates with the nepheline-kalsilite framework and molten MNO3 or MO (M = Li, Na, K, Ag)

Reference samples in geology and geochemistry

Geologia e Petrologia da suíte alcalina de Bom Repouso, MG

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