Want to know the molecular size of some heavy metals 1

[lpy2000]

Hello everyone,
I am glad to find such a good forum like this and this is my first time to post a question in this forum. I am now doing a research on the adsorption of heavy metals using some bio-material. Things i would like to know in order to explain the adsorption mechanism is the molecular size of Copper, Cadmium, Lead, Nickel and Zinc.
What in my sound is that molecular size is some thing different from molecular weight but i really don't know where to find such data. How small is it (nm)? how the molecular structure of these heavy metal(3D)look like? How to measure it? Using XRD? any website or reference where i can find these data?

Best regards,
LPY

 

[25362]

The atomic radiuses are around 100-200 pm. 1 pm = 10^-12m. However, these atoms tend to form complex ions as, for example, [Cu(NH₃)₄]²⁺, [Cu(H₂O)₄]²⁺, [Ni(CN)₄]²⁺, and may be you need to find their sizes rather than those of the bare metal ions, which by being deprived of 1 or 2 electrons may have radiuses smaller than 100 pm.

For more details good chemistry books should be of help.

 

[amorrison]

Check out "atomic volume" in a mass transfer text.

Note that the volume of a molecule can be very different than its atomic constituents.
Ex. one oxygen atom is 7.4(units) while O2 is 25.6(units).

 

[25362]

Atomic species would be around 0.5 nm.

 

[25362]

BTW, I know remember somebody asked some time ago about the molecular size of an organic compound.
Donald R. Woods in his Process Design and Engineering Practice -Prentice Hall-, Figure 4-3, relates molecular mass to molecular size.

Reading his diagram, masses from 100 to 1000 would correspond to sizes 0.7 to 1.4 nm, respectively. Masses are on a linear scale while sizes apparently are on a log scale. An example therein: a triglyceride oil with a molar mass of 900 would have a "size" of 1.3 nm.