* Composition: Cupro-nickel is an alloy, which means it's a mixture of two or more metals. In this case, it's primarily composed of copper (Cu) and nickel (Ni).

* Chemical Bonding: The elements in a mixture retain their individual chemical properties. In cupro-nickel, copper and nickel are not chemically bonded together to form a new substance.

* Variable Composition: Alloys can have varying proportions of their constituent metals. This means the exact composition of cupro-nickel can change, unlike a compound which has a fixed, definite composition.

In summary: While cupro-nickel is a very useful material, it's a blend of metals rather than a single new substance formed by chemical bonding.