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Date: 5-1-2019
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Date: 12-1-2018
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Date: 14-12-2018
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Occurrence of the group 13 elements
The relative abundances of the group 13 elements are shown in Figure 1.1. The main sources of boron are borax, Na2 [B4O5(OH)4]. 8H2O, and kernite, Na2 [B4O5(OH)=]. 2H2O, with extensive deposits being worked commercially in the Mojave Desert, California. Aluminium is the most abundant metal in the Earth’s crust, and occurs in aluminosilicates (see Section 13.9) such as clays, micas and feldspars, in bauxite (hydrated oxides) and, to a lesser extent, in cryolite, Na3[AlF6]. Gallium, indium and thallium occur in trace amounts as sulfides in various minerals.
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"إنقاص الوزن".. مشروب تقليدي قد يتفوق على حقن "أوزيمبيك"
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الصين تحقق اختراقا بطائرة مسيرة مزودة بالذكاء الاصطناعي
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قسم شؤون المعارف ووفد من جامعة البصرة يبحثان سبل تعزيز التعاون المشترك
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