Methods of optical spectroscopy and X-ray crystallography data were used to examine the effect of architecture of carboxylate anions on structure of the Eu3+ coordination centre in europium carboxylates with 1,10-phenanthroline Eu(RCOO)3·Phen. Luminescence spectra of europium acetate, nitropropionate, benzoate, naphthylcarboxylates, phenylacetates, phenoxyacetate, triphenylpropionate were in- vestigated. A few of europium carboxylates with 2,2’-bipyridine Eu(RCOO)3·Bpy and europium salts Eu(RCOO)3·nH2O were also studied. Vibrational IR and Raman spectra of phenylacetate family were analyzed. The crystal structure of nitropropionate Eu(NO2C2H4COO)3·Phen was solved by X-ray diffraction method. The predominant influence of steric hindrances on Eu3+ coordination centre was observed at in- crease of the size of aromatic fragment of carboxylate anions. It was demonstrated, that introduction of the methylene bridges between the carboxylic group and aromatic rings of ligand weakens the effect of steric factor. Methods of optical spectroscopy and X-ray crystallography data were used to examine the effect of architecture of carboxylate anions on structure of the Eu3 + coordination center in europium carboxylates with 1,10-phenanthroline Eu (RCOO) 3 · Phen. Luminescence spectra of europium acetate A few of europium carboxylates with 2,2’-bipyridine Eu (RCOO) 3 · Bpy and europium salts Eu (RCOO) 3 · nH2O were also studied. The crystal structure of nitropropionate Eu (NO2C2H4COO) 3 · Phen was solved by X-ray diffraction method. The predominant influence of steric hindrances on Eu3 + coordination center was observed at in- crease of the size of aromatic fragment of carboxylate anions. It was demonstrated, that introduction of the methylene bridges between the carboxylic group and aromatic rings of ligand weakens the eff ect of steric factor.