I just had a poke about on google, each iron is octahedrally co-ordinated (ie to six chlorines), and has a monoclinic unit cell - but i couldn't fint any pics
I suggest having a look in "chemistry of the elements" by Greenwood and Earnshaw, it might be in "inorganic chemistry" by shriver and atkins - and if it is you will get a nice picture which you probably won't get in greenwood and earnshaw.
Try inorganic chemistry textbooks anyway.
I don't have my textbooks to hand at the moment.