▁is ▁he ated ▁strongly , ▁and ▁the ▁accurate ▁weight ▁of ▁a ▁sample ▁is ▁pl otted ▁against ▁the ▁temperature . ▁The ▁amount ▁of ▁water ▁driven ▁off ▁is ▁then ▁divided ▁by ▁the ▁mol ar ▁mass ▁of ▁water ▁to ▁obtain ▁the ▁number ▁of ▁mole cules ▁of ▁water ▁bound ▁to ▁the ▁salt . ▁ ▁Other ▁sol vent s ▁of ▁cry st all ization ▁Water ▁is ▁particularly ▁common ▁sol vent ▁to ▁be ▁found ▁in ▁cry st als ▁because ▁it ▁is ▁small ▁and ▁polar . ▁ ▁But ▁all ▁sol vent s ▁can ▁be ▁found ▁in ▁some ▁host ▁cry st als . ▁ ▁Water ▁is ▁not ew orth y ▁because ▁it ▁is ▁re active , ▁whereas ▁other ▁sol vent s ▁such ▁as ▁ben z ene ▁are ▁considered ▁to ▁be ▁chem ically ▁innoc uous . ▁ ▁Occ asion ally ▁more ▁than ▁one ▁sol vent ▁is ▁found ▁in ▁a ▁cry stal , ▁and ▁often ▁the ▁sto ichi ometry ▁is ▁variable , ▁reflected ▁in ▁the ▁cry stal log raph ic ▁concept ▁of ▁" partial ▁occup ancy ." ▁It ▁is ▁common ▁and ▁conventional ▁for ▁a ▁chem ist ▁to ▁" d ry " ▁a ▁sample ▁with ▁a ▁combination ▁of ▁vac u um ▁and ▁heat ▁" to ▁constant ▁weight ." ▁ ▁For ▁other ▁sol vent s ▁of ▁cry st all ization , ▁analysis ▁is ▁convenient ly ▁accomplished ▁by ▁dissol ving ▁the ▁sample ▁in ▁a ▁de uter ated ▁sol vent ▁and ▁analyz ing ▁the ▁sample ▁for ▁sol vent ▁signals ▁by ▁N MR ▁spect ro sc opy . ▁Single ▁cry stal ▁X - ray ▁cry stal log raph