• Question: What are Gold Nanoparticles?

    Asked by anon-199626 to Sylvia, Sumit, Martin, Kate, Bryony, Aryanne on 4 Mar 2019.
    • Photo: Martin McCoustra

      Martin McCoustra answered on 4 Mar 2019:

      You can think of a gold nanoparticle as a small fleck of gold in which basically every atom is at or near the surface of the particle. This is only possible with a few 10s to 100s of gold atoms in total!

    • Photo: Sylvia Soldatou

      Sylvia Soldatou answered on 5 Mar 2019:

      I don’t have any experience on gold nanoparticles but I think Aryanne would be the person to answer your question!

    • Photo: Kate McGonagle

      Kate McGonagle answered on 5 Mar 2019:

      I don’t know much about gold nanoparticles! So interesting though! Maybe you should ask this question specifically to Aryanne as she seems to be doing a lot of work on these. Sorry I’m not more helpful!

    • Photo: Sumit Konar

      Sumit Konar answered on 5 Mar 2019:

      do you know how big is an gold atom? it is 166 picometre = 0.166 nanometre. now think about a cube. you have 8 corners and 6 edges. You will find 1 gold atom in each corner and at the middle of the edge. so how many gold atoms you need to make one gold cube? 8 +6 = 14; right? Now I ask you to put such gold cubes in all three dimensions. What will happen? Corners and edge golds will share with their neighbours. If we consider this sharing, then 1 gold cube has only 4 gold crystals (8 corner X 1/8 and 6 edge X 1/2 = 1+ 3 =4. (Ask your teacher to help you to understand). Therefore 4 gold atoms make 1 gold crystal. all the atoms do not touch each other, there is always some empty space in the crystal. One gold cube is 0.0679 cubic nanometre (each side of the cube is 0.408 nm, volume of cube V = L 3).
      Now what is nano particles? nanopraticles are formed with hundreds to thousands of gold cubes and they look like sphere with diameter between 1-100 nm. Different size gold nano particles have different colours. Now depending on the size of your gold nanoparticles you can fit as many cubes as possible. Now can you calculate how many gold atoms will be present for a 2 nm diameter gold nano particle? ask your teacher for help. Otherwise, I am happy to help you. Isn’t it cool?

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