Direct Oxidation of Europium Metal with Acetic Acid: Anhydrous Europium(III) Acetate, Eu(OAc)3, its Sesqui‐hydrate, Eu(OAc)3(H2O)1.5, and the “Hydrogendiacetate”, [Eu(H(OAc)2)3](H2O)

Abstract

AbstractAnhydrous europium(III) acetate, Eu(OAc)3 (1), its sesquihydrate Eu(OAc)3(H2O)1.5 = [Eu2(OAc)6(H2O)](H2O)2 (2) and the “hydrogendiacetate” [Eu(H(OAc)2)3](H2O) = [Eu2(OAc)6(HOAc)2(H2O)2](HOAc)4 (3) were obtained as colourless single crystals by direct oxidation of europium metal with acetic acid in glass ampoules at 130 °C. The coordination polymer Eu(OAc)3 (1) crystallizes in the monoclinic space group C2/c (no. 15) with a = 1126.0(3), b = 2900.5(6), c = 799.1(2) pm, β = 132.03(2)°, V = 1938.6(8) 106·pm3, Z = 4, R1 = 0.0374 [I>2σ]. The crystals of Eu(OAc)3(H2O)1.5 (2) are monoclinic, space group Cc (no. 9) with a = 1608.7(2), b = 1665.6(2), c = 839.1(1) pm, β = 115.75(9)°, V = 2025.2(4) 106·pm3, Z = 4, R1 = 0.0424 [I>2σ]. [Eu(H(OAc)2)3](H2O) (3) crystallizes in the monoclinic space group P21/c (no. 14) with lattice parameters of a = 1157.7(1), b = 2131.6(3), c = 901.3(1) pm, β = 110.36(1)°, V = 2085.6(4) 106·pm3, Z = 4, R1 = 0.0331 [I>2σ]. The linear chain structure of 1 is modified by the addition of one coordinating water molecule in 2 to a corrugated chain whose packing leaves room for crystal water. In 3 the same dimers are observed as in [Eu2(OAc)6(HOAc)2(H2O)2] (4) itself which had previously been synthesized from an ammonium acetate melt. With a higher acetic acid pressure, four molecules of acetic acid per dimer are included in the structure in 3.