• H Cl ) 2 • P t Cl 4 • H 2 O , ▁separ ates ▁from ▁concentr ated ▁solution ▁as ▁an ▁oil , ▁which ▁solid ifies ▁to ▁a ▁mass ▁of ▁orange - yellow ▁cry st als , ▁mp . ▁ 1 7 5   ° C ▁( d ry ). ▁The ▁aur ich lor ide , ▁B • HA u Cl 4 , ▁cry st all izes ▁on ▁standing , ▁mp . ▁ 7 7   ° C . ▁The ▁pic rate ▁forms ▁small ▁yellow ▁need les , ▁mp . ▁ 7 5   ° C , ▁from ▁hot ▁water . ▁The ▁ 2 , 4 - d init ro ben zo yl - ▁and ▁ 3 , 5 - d init ro ben zo yl - der iv ates ▁have ▁m ps . ▁ 1 3 9 . 0 – 1 3 9 . 5   ° C ▁and ▁ 1 0 8 – 9   ° C ▁respectively . ▁The ▁precip itate ▁afford ed ▁by ▁pot ass ium ▁cad m ium ▁i od ide ▁solution ▁is ▁cry st all ine , ▁mp . ▁ 1 1 8   ° C , ▁while ▁that ▁given ▁by ▁nic ot ine ▁with ▁this ▁re agent ▁is ▁am orph ous . ▁ ▁Color ▁changes ▁Con i ine ▁gives ▁no ▁color ation ▁with ▁sul fur ic ▁or ▁nit ric ▁acid . ▁S od ium ▁nit ro pr uss ide ▁gives ▁a ▁deep ▁red ▁color , ▁which ▁disapp ears ▁on ▁war ming , ▁but ▁re