AnaAnaly show that FeO has a non-stoichiometric composition with formula Fe0.95O. Give reasons

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The non-stoichiometry occurs because of the instability in the FeO molecule as undergo the oxidation of Fe+2 to Fe+3 effectively replacing a small portion of Fe+2 with two thirds their number of Fe+3. Thus for every three "missing" Fe+2 ions, the crystal contains two Fe+3 ions to balance the charge.  This change in composition violets the law of constant composition as the composition of the compound usually varies in a continuous manner over a narrow range. Thus FeO becomes a non-stoichiometric compound and the formula is written as Fe(1-x)O, where x is a small number representing the deviation from the "ideal" formula.Generally, it is written as Fe0.95O or found in the form of FeO.Fe2O3 represented as Fe3O4.