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離子晶體之熔點高低

離子晶體之熔點高低. 離子晶體之熔點高低. 離子鍵越強，則離子鍵能 (E) 越大  造成離子晶體的 熔點越高 。 Ⅰ A X 、 Ⅱ A O 型 ： ( Ⅰ A 的鹵化物或 Ⅱ A 的氧化物；簡稱 1 ： 1 型 ) (1) 此類離子晶體電荷密度 (q/r) 越大，則離子鍵強度越強，熔點越高。 (2) 即電荷 (q) 越大，半徑 (r) 越小 ( 先比電荷再比半徑 ) ，離子鍵越強，熔點越高。 (3) 例 ： ( 熔點 ) MgO(2800℃) > CaO(2580℃) > NaF(993℃) >

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離子晶體之熔點高低

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  1. 離子晶體之熔點高低

  2. 離子晶體之熔點高低 • 離子鍵越強，則離子鍵能(E)越大造成離子晶體的熔點越高。 • ⅠAX、ⅡAO型：(ⅠA的鹵化物或ⅡA的氧化物；簡稱1：1型) • (1)此類離子晶體電荷密度(q/r)越大，則離子鍵強度越強，熔點越高。 • (2)即電荷(q)越大，半徑(r)越小(先比電荷再比半徑)，離子鍵越強，熔點越高。 • (3)例：(熔點) MgO(2800℃) > CaO(2580℃) > NaF(993℃) > • NaCl(801℃) >NaBr(755℃) > NaI(651 ℃)

  3. 離子晶體之熔點高低 • 先比電荷(q) Mg2+O2-、Ca2+O2-；Na+F-、Na+Cl-、Na+Br-、Na+I-電荷(q)相同 MgO、CaO之電荷皆比NaF、NaCl、NaBr、NaI大離子鍵強度以MgO、CaO最強 MgO(2800℃) > CaO(2580℃) > NaF(993℃) > NaCl(801℃) >NaBr(755℃) > NaI(651 ℃) • 電荷(q)相同則比半徑(r) • r : Mg<Ca、F<Cl<Br<I半徑越小離子鍵強度越強 • r↓ q/r↑ mp↑ MgO(2800℃) > CaO(2580℃) > NaF(993℃) > NaCl(801℃) >NaBr(755℃) > NaI(651 ℃)

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