The crystals were potassium chloride, KCl.
“Potassium dichromate pumpkins
Iron (II) thiocyanate blood
Dripping down diamond fangs
Graphene cloak with a buckyball hood
Sodium chromate bats eyes
Witches stir in the brew
Copper (II) chloride frogs
And potassium permanganate too
Dip copper in silver nitrate
To precipitate werewolves howl
Silver sparkles in the night sky
Before the auric hour”
Here is another picture of three potassium salts; potassium chloride KCl, potassium bromide KBr and potassium iodide KI.
All three are white, crystalline, ionic solids. What is interesting is their shapes, the first two are cubic, whilst potassium iodide crystallises as tufts of finger-like spikes.
What would you predict about the colour and shape of sodium chloride NaCl, sodium bromide NaBr and sodium iodide NaI?