Electronegativity of element X is 2.20 and electronegativity of element Y is 2.55. The compound formed between them is covalent.
Covalent compound
If the difference in the electronegativity values of elements in a compound is 1.7 or greater, the compound is generally ionic compounds and if it is less than 1.7, the compound is generally a covalent compound.
The difference in electronegativity of constituent elements is 2.55−2.0=0.55<1.7
Hence the compound formed is covalent in nature.