OK, I'm trying to calculate the density of an ideal NaCl crystal for a lab report. I know I messed up some where. Can anyone point me in the right direction?

Heres what I have:

4NaCl M = 233.768 amu. V= (283 pm x 2)^3 = 80089 pm3

233.768amu / 80089 pm X 1E10 pm/ 1 cm X 1g/6.022 E23 amu = 3.19066 E -14 g/cm^3

now I'm not a rocket scientist (physics isn't until next year

) but I know a cm^3 of salt weighs a LOT more than that.

Thanks in advance for any help you may be able to offer. I did a search on the boards here and couldn't seem to turn up anything.