Which word signifies that two elements cannot coexist?

The term "incompatible" specifically refers to the inability of two elements to exist together harmoniously, highlighting their mutual exclusivity or opposition. When elements are described as incompatible, it means that their characteristics or nature prevent them from functioning or existing together effectively. This word is commonly used in contexts such as relationships, substances in chemistry, or ideas that conflict fundamentally.

On the other hand, "compatible" refers to elements that can coexist without issue, while "complementary" indicates that two elements enhance or complete each other. "Analogous" describes a relationship based on similarity rather than conflict. Therefore, the correct word to convey the concept of non-coexistence among elements is clearly "incompatible."