Okay so our compound is [Et4N[Hg(SR)3] aka (C26H53HgNS3) Formula weight 676.5

Volume= 1531.3A^3 and density = 1.467gcm^-3 Where R= Cyclohexyl group C6H11

Okay so first I calculated the Z value, converting both volume and density in to metres

Z= (DensityxvolumexNA)/RMM which gave me a value of essentially 2 (No solvent molecules present)

Then to calculate the average volume of non-H atoms I used Cell volume/(ZXnumber of H atoms)

1531.3/(31x2) gave me a value of 28, why does this not fit the rule? I'm guessing it has somethibg to do with the size of the ligands and Hg atoms but not entirely sure

Thanks in advance