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Date: 26-2-2019
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Date: 27-4-2019
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Date: 1-1-2017
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Aluminosilicate minerals are silicates when some of the Si4+ ions in silicates are replaced by Al3+ ions. For each Si4+ ion replaced by an Al3+ , the charge must be balanced by having other positive ions such as Na+, K+, and (Ca^{2+}) ions. Feldspar group and zeolites are typical aluminosilicates by this definition. Examples of minerals belong to the feldspar group include:
The alkali ions are held in place to balance the charges due to the presence of Al3+ ions instead of Si4+ ions. The Al3+ ions seem replace Si4+ ions in the chains of corner shared tetrahedra of SiO4 groups. However, the bonding between Al and Si can be different. Silicon atoms or ion tend to be bonded to 4 oxygen atoms in a tetrahedral fashion, but aluminum ions tend to be bonded to 6 oxygen atoms in an octahedral fashion.
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تفوقت في الاختبار على الجميع.. فاكهة "خارقة" في عالم التغذية
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أمين عام أوبك: النفط الخام والغاز الطبيعي "هبة من الله"
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قسم شؤون المعارف ينظم دورة عن آليات عمل الفهارس الفنية للموسوعات والكتب لملاكاته
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