What knows the precise radius of these ions?

[hlxworenwei]

Pb2+, La3+, Ti4+, O2-

I am very grateful for your help!

 

[interested_learner]

Atoms don't have precise radii. See:

http://www.chemguide.co.uk/atoms/properties/atradius.html

and

http://en.wikipedia.org/wiki/Ionic_radius

for good discussions.

 

[Astronuc]

Webelements has such information.


For example -

http://www.webelements.com/webelements/elements/text/Pb/radii.html

http://www.webelements.com/webelements/elements/text/La/radii.html
http://www.webelements.com/webelements/elements/text/La/vrad.html

Just substitute the element's symbol in the links. Note that there are different ways to measure the radius, or the radius depends on the compound.