Title: The geometry of the nonaaqualanthanoid(3+) complex in the solid bromates and ethyl sulphates
Abstract:The structures of [Ln(H20)9I(BrO3) 3 and ILn(H20)gI(CzHsSO4)3, Ln = Pr and Yb, have been determined by X-ray diffraction. The structures were refined to R = 0.025--0.040. Accurate cell dimensions for ...The structures of [Ln(H20)9I(BrO3) 3 and ILn(H20)gI(CzHsSO4)3, Ln = Pr and Yb, have been determined by X-ray diffraction. The structures were refined to R = 0.025--0.040. Accurate cell dimensions for the bromates and ethyl sulphates of all the trivalent Ln ions except Pm were determined at 23°C with Guinier-H~igg powder photographs. The bromates crystallize in the space group P63/mmc with Z = 2, a = 11.8395 (11), c = 6.8012 (9)/~ for Pr and a = 1 I. 7056 (13), c = 6-6474 (9) A for Yb. The ethyl sulphates crystallize in space group P6ffm with Z = 2, a -14.0454 (8), c = 7. 1207 (6)/~ for Pr and a = 13.8991 (8), c -7.0247 (6) ,~ for Yb. Tricapped trigonal prisms of water O atoms with symmetry D3h in the bromates and C3h in the ethyl sulphates surround the nine-coordinated Ln ions. The complex ions form columns about the 6 axes. The anions are hydrogen-bonded to the complex ions and form columns about the 63 axes. The decrease in the prismatic Ln-O bonds between the Pr and Yb structures is what is expected from the lanthanoid contraction, 0.155 ,/~, but van der Waals repulsions between prismatic and equatorial O atoms make the decrease in the equatorial Ln--O bonds about hal f this value. The variation in cell dimensions through the Ln series for both types of compounds has been related to this repulsion and to the hydrogen-bond systems.Read More
Publication Year: 1977
Publication Date: 1977-05-15
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 108
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