I've Googled variations on poisonous chemicals in school, toxic chemicals, school laboratory stock, school chemicals, list of chemicals in school etc, and I can't find what I'm looking for.
I'm obviously not a chemist, and I know that schools wouldn't have anything so dangerous that a fraction of a gram could kill - but does anybody know if the average chemistry department stock cupboard would have something that would be lethal, in a big enough dose? Or something that could be combined with something else? I'm aware that basic things can be lethal if you have too much of them, but I'm really looking for something that is a bit unusual, or exotic.
I'm sorry this is a bit vague, but I'm still in the plot development stage at the moment. Thanks to anybody that can help!