What are alkaloids known for in terms of their composition?

Alkaloids are primarily known for their unique physical properties, one of which is that they typically exist in crystalline or liquid form. This characteristic arises from their chemical structure, which is often complex and includes nitrogen atoms. The crystalline structure allows many alkaloids to be extracted and purified from plants, contributing to their use in various medicinal formulations.

While some alkaloids can be toxic, others have beneficial pharmacological effects and can be safely consumed in moderated doses. This distinguishes them from being strictly labeled as non-toxic or edible, as their effects can largely depend on the specific type and concentration. Furthermore, alkaloids are not carbohydrates; they belong to a distinct class of organic compounds that also includes various nitrogen-containing compounds. Thus, the identification of alkaloids as being in crystalline or liquid form is a defining and accurate characteristic.