[jclough]

Hi all,

I have a small conundrum...

CaC2 and CaSi2 are valence-isoelectronic. However, CaC2 has discrete units of two carbon atoms with a 2- charge while CaSi2 has black P-like layers of (Si-) sheets (which is the expected structure, based on the isoelectronic analogy). Does the difference result from the size of the C/Si atom?

Any ideas would be much appreciated!

Jessica.

[Borek]

Size difference, bond energies, electronegativity...

[jclough]

Oh, Ok... I thought it would be something more interesting... and correspondingly more complicated...