Caesium ethanoate ( caesium acetate).
The formula may be better under stood as 'CH3COO^- Cs^+'.
The CH3COO^- is the ethanoate ion and the Cs^+ is the caesium ion.
The caesium has substituted in for an hydrogen 'CH3COOH' Ethanoic (Acetic) acid.
You have too many C's and O's
If the compound you mean is CsC2H3O2, it is Cesium Acetate.