ens it ization ▁occurs ▁at ▁the ▁n erve ▁terminal , ▁and ▁the ▁my ocy te ▁becomes ▁less ▁sensitive ▁to ▁ac et yl ch oline ; ▁the ▁memb rane ▁rep olar izes ▁and ▁cannot ▁be ▁dep olar ized ▁again . ▁ ▁Chem istry ▁S ux am eth on ium ▁is ▁an ▁od or less , ▁white ▁cry st all ine ▁subst ance . ▁A que ous ▁solutions ▁have ▁a ▁p H ▁of ▁about ▁ 4 . ▁The ▁di h yd rate ▁mel ts ▁at ▁ 1 6 0   ° C , ▁whereas ▁the ▁an h yd r ous ▁mel ts ▁at ▁ 1 9 0   ° C . ▁It ▁is ▁highly ▁sol ub le ▁in ▁water ▁( 1   gram ▁in ▁about ▁ 1 ▁m L ), ▁sol ub le ▁in ▁eth yl ▁alco hol ▁( 1   gram ▁in ▁about ▁ 3 5 0 ▁m L ), ▁slightly ▁sol ub le ▁in ▁ch lor o form , ▁and ▁pract ically ▁ins ol ub le ▁in ▁ ether . ▁ ▁S ux am eth on ium ▁is ▁a ▁h yg ro scop ic ▁comp ound . ▁The ▁comp ound ▁consists ▁of ▁two ▁ac et yl ch oline ▁mole cules ▁that ▁are ▁linked ▁by ▁their ▁ac et yl ▁groups . ▁It ▁can ▁also ▁be ▁viewed ▁as ▁a ▁central ▁mo iety ▁of ▁succ in ic ▁acid ▁with ▁two ▁ch oline ▁mo iet ies , ▁one ▁on ▁each ▁end . ▁ ▁History ▁S ux am eth on ium ▁was ▁first ▁discovered ▁in ▁ 1 9