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Date: 24-10-2018
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Date: 15-1-2019
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Date: 4-12-2018
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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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مخاطر خفية لمكون شائع في مشروبات الطاقة والمكملات الغذائية
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"آبل" تشغّل نظامها الجديد للذكاء الاصطناعي على أجهزتها
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الزائرون يحيون ليلة الجمعة الأخيرة من شهر ربيع الآخر عند مرقد أبي الفضل العبّاس (عليه السلام)
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