▁Dark ▁brown ▁i od ine ▁mon och lor ide ▁liquid ▁is ▁collected . ▁Ex cess ▁ch lor ine ▁converts ▁i od ine ▁mon och lor ide ▁into ▁i od ine ▁tr ich lor ide ▁in ▁a ▁revers ible ▁reaction : ▁ ▁Pol ym orph s ▁ ▁has ▁two ▁polym orph s ; ▁, ▁which ▁exists ▁as ▁black ▁need les ▁( red ▁by ▁transm itted ▁light ) ▁with ▁a ▁mel ting ▁point ▁of ▁ 2 7 . 2   ° C , ▁and ▁, ▁which ▁exists ▁as ▁black ▁plate lets ▁( red - b rown ▁by ▁transm itted ▁light ) ▁with ▁a ▁mel ting ▁point ▁ 1 3 . 9   ° C . ▁ ▁In ▁the ▁cry stal ▁structures ▁of ▁both ▁polym orph s ▁the ▁mole cules ▁are ▁arranged ▁in ▁z ig z ag ▁ch ains . ▁ ▁is ▁mon oc lin ic ▁with ▁the ▁space ▁group ▁P 2 1 / c . ▁ ▁Re actions ▁and ▁uses ▁ ▁I od ine ▁mon och lor ide ▁is ▁sol ub le ▁in ▁ac ids ▁such ▁as ▁H F ▁and ▁H Cl ▁but ▁react s ▁with ▁pure ▁water ▁to ▁form ▁H Cl ▁and ▁i od ine : ▁▁▁ 4 ▁I Cl ▁+ ▁ 2 ▁H 2 O ▁→ ▁ 4 ▁H Cl ▁+ ▁ 2 ▁I 2 ▁+ ▁O 2 ▁▁ ▁is ▁a ▁useful ▁re agent ▁in ▁organ ic ▁synth esis . ▁ ▁It ▁is ▁used ▁as ▁a ▁source ▁of ▁elect roph il ic ▁i od ine ▁in ▁the ▁synth esis ▁of ▁certain ▁a rom