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  1. #1
      Eiman
    Jul 2011
    -
    14,750

    . .




    : (nonmagnetic)
    : 2349 K (3769 F)
    : 4200 (7101 F)
    4.39: 10-6 3/
    Heat of vaporization 489.7
    Heat of fusion 50.2
    0.348 Pa at 2573 K
    16200 m/s at 293.15 K

    :

    : (sodium tetraborate decahydrate)Na2B4O7 10H2O) Na2B4O7.4H2O 2Mg3BO8O15 H3BO3 .

    :

    1- :


    H2B4O7 H3BO3 B2O3 .

    Na2B4O7 + 2HCl---> 2NaCl +H2B4O7
    H2B4O7+ 5H2O --->4H3BO3
    2H3BO3 --->B2O3 +3H2O

    :

    B2O3 + 6K ---> 2B + 3K2O3
    B2O3 + 3Mg---> 2B + 3MgO

    <span style="color:#006600">2- :

    :

    KBF4 + 3K ---> B + 4FK
    2KBF4 + 3Mg ---> 2B 2KF + 3MgF2

    .
    2BBr3 + 3H2 ----> 2B + 6HBr
    .......

  2. #2

    Jul 2011
    -
    15,678

    :




  3. #3

    Aug 2011
    -
    2,565

    :

    Thank you
    You are great

    ..

  4. #4

    Jul 2011
    -
    1,260

    :





  5. #5

    Jul 2012
    5,302

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