Final answer:
An amorphous solid lacks definite regularity or order in its molecular structure, as opposed to crystalline solids which have a regular repeating structure. Examples include candle waxes and glass.
Step-by-step explanation:
A substance whose molecules have no definite regularity or order is known as an amorphous solid. These solids differ from crystalline solids, which have a regular and repeating three-dimensional structure, such as metals and ionic compounds like NaCl. Amorphous solids, such as candle waxes and glass, are made up of large molecules or a mixture of molecules that do not form a regular pattern. These substances can sometimes transition to a more ordered crystalline state under certain conditions, although they are typically characterized by their randomness and lack of a structured form.
For instance, silicon dioxide and boron oxide can each form either crystalline or amorphous solids, depending on the specific conditions during their production. However, most commonly encountered solids, including those that make up the Earth's crust, do not consist of identifiable molecules, similarly to how atoms in glasses are held together without a regular pattern. This absence of a clear, repeating pattern is what distinguishes amorphous solids from their crystalline counterparts.
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