▁cub ic ▁z inc bl ende ▁form . ▁ ▁P ig ment ▁production ▁usually ▁involves ▁the ▁precip itation ▁of ▁C d S , ▁the ▁was hing ▁of ▁the ▁solid ▁precip itate ▁to ▁remove ▁sol ub le ▁cad m ium ▁sal ts ▁followed ▁by ▁calc ination ▁( ro ast ing ) ▁to ▁convert ▁it ▁to ▁the ▁hex ag onal ▁form ▁followed ▁by ▁mill ing ▁to ▁produce ▁a ▁pow der . ▁When ▁cad m ium ▁sul f ide ▁s elen ides ▁are ▁required ▁the ▁C d Se ▁is ▁co - pre cip itated ▁with ▁C d S ▁and ▁the ▁cad m ium ▁sul f os elen ide ▁is ▁created ▁during ▁the ▁calc ination ▁step . ▁ ▁Cad m ium ▁sul f ide ▁is ▁sometimes ▁associated ▁with ▁sul f ate ▁reducing ▁b acter ia . ▁ ▁Rout es ▁to ▁thin ▁films ▁of ▁C d S ▁Special ▁methods ▁are ▁used ▁to ▁produce ▁films ▁of ▁C d S ▁as ▁components ▁in ▁some ▁phot ores ist ors ▁and ▁solar ▁cells . ▁In ▁the ▁chemical ▁bath ▁de position ▁method , ▁thin ▁films ▁of ▁C d S ▁have ▁been ▁prepared ▁using ▁th i ou rea ▁as ▁the ▁source ▁of ▁sul f ide ▁an ions ▁and ▁an ▁am mon ium ▁buffer ▁solution ▁to ▁control ▁p H : ▁ ▁C d 2 + ▁ ▁+ ▁H 2 O ▁▁ ▁+ ▁ ▁( N H 2 ) 2 CS ▁ ▁+ ▁▁ 2 ▁N H 3 ▁ ▁→ ▁▁ ▁C d S ▁ ▁+ ▁ ▁( N H 2 ) 2 CO ▁▁ ▁+