Maybe I confused the question by asking about the direction of the screw
axis. I'm referring to the top and base of the actual crystal. If all
the molecules in the unit cell are oriented in the same direction (with
respect to the c cell), I want to know if there is a way to find out
which direction those molecules are going in the physical crystal.
On 06/01/2015 12:59 PM, David Schuller wrote:
> The screw axis is either left-handed or right-handed (And the
> enantiomer, P62, will twist the opposite way). Therefore it doesn't
> even matter which you call the "top" and which you call the "base."
> So, what exactly do you find confusing?
> On 06/01/15 12:20, Paul Paukstelis wrote:
>> I'm interested in knowing how to figure out the relationship between
>> the unit cell contents and the crystal habit in these crystals (small
>> attachment, two roughly orthogonal views).
>> Space group is P64 (enantiomeric) , and you can clearly see the
>> six-fold. The question becomes how to determine which direction the
>> screw axis is going with respect to "top" and the "base" of the
>> pyramidal crystals (right image) so I can gauge how/why the crystals
>> grow this way based on the cell contents.
>> Thanks in advance.