PUMA
Istituto di Geoscienze e Georisorse     
Bindi L., Bonazzi P., Fitton J. Crystal chemistry of strontian soda melilite from nephelinite lava of Mt. Etinde, Cameroon. In: European Journal of Mineralogy, vol. 13 (1) pp. 121 - 125. Schweizerbart, 2001.
 
 
Abstract
(English)
The crystal structure and chemical composition of two crystals (labelled ET1 and ET2) of strontian soda melilite from Mt. Etinde, Cameroon , are investigated. Quantitative analysis leads to the following formulae: (Ca₀.₈₄Sr₀.₄₅Na₀.₇₁)(Mg₀.₁₉Fe▓⁺₀.₀₆Mn₀.₀₃Zn₀.₀₂Al₀.₄₆Fe│⁺₀.₂₃Ti₀.₀₁)(Si₁.₉₉Al₀. and (Ca₀.₈₃Sr₀.₄₅Na₀.₇₂) (Mg₀.₂₀Fe▓⁺₀.₀₆Mn₀.₀₃Zn₀.₀₁Al₀.₄₅Fe│⁺₀.₂₄Ti₀.₀₂)(Si₁.₉₉Al₀.₀₁)O₇.₀₀, for ET1 and ET2 respectively. Lattice parameters are: a = 7.754(1), c = 5.101(1) ┼ for ET1 and a = 7.764(1), c = 5.095(1) ┼ for ET2. The structure is refined up to R_(all) = 2.64 and 2.78 %, respectively, using 430 independent reflections. Substitution of Sr for Ca causes sufficient modification of the tetrahedral layer to destabilize the incommensurate modulated structure.
URL: http://www.schweizerbart.de/j/ejm/
DOI: 10.1127/0935-1221/01/0013-0121
Subject strontian soda melilite
crystal chemistry
single-crystal X-ray diffraction
Etinde
Cameroon


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