Cholic acid forms inclusion compounds with acetone, methyl ethyl keton
e and diethyl ketone. Crystal structures with these closely related gu
est molecules indicate variations in packing which result in respectiv
ely: unusual 2:3 host:guest stoichiometry and loss of the 2(1) screw a
xis, doubling of the c axis with formation of two different channels a
nd the usual P2(1) structure with 1:1 host:guest stoichiometry.