I. INTRODUCTION
Lanthanum is an important rare earth element used in many applications such as hydride batteries, high temperature superconductors or heavy fluoride glass. Recently, rare earth fluorides have attracted lot of attention because of their unique properties namely luminescent properties in nanoparticle forms.
Various salts of rare earths are used as precursors for nano-fluorides when various organic and inorganic precursors take place (Bartůněk et al., Reference Bartůněk, Rak, Sofer and Král2013; Zhang et al., Reference Zhang, Su, Zhang and Yan2010; Zhang and Huang, Reference Zhang and Huang2010). Studies of rare earths lactates including lanthanum lactate are also important for the advanced nuclear fuel cycles technologies where lactates can play crucial role in actinides and lanthanides separations (Tian et al., Reference Tian, Martin and Rao2010; Zalupski et al., Reference Zalupski, Nash and Martin2010).
II. EXPERIMENTAL
A. Sample preparation
Lanthanum trilactate was prepared by neutralization reaction of 50% lactic acid with lanthanum oxide under air atmosphere at approximately 50 °C. Reaction was carried out until neutral pH and the product subsequently filtered and obtained by free crystallization in pure form. Crystals were subsequently dried in a desiccator. Pale blue crystals of tris[2-(hydroxy-κO)propanoato-κO]lanthanum trihydrate (Figure 1) were milled and subsequently analyzed. All chemicals were used in pure form. The water content was determined by single-crystal structure analysis.
Structural formula of the title compound tris[2-(hydroxy-κO)propanoato-κO]lanthanum trihydrate.
B. Diffraction data collection and reduction
The diffraction pattern for the title compound was collected at room temperature using an X'Pert PRO θ–θ powder diffractometer with parafocusing Bragg–Brentano geometry and CuKα radiation (λ = 1.5418 Å, generator setting: 40 kV, 30 mA). An ultrafast X'Celerator detector was employed to collect XRD data over the angular range from 4 to 60 °2θ with a step size of 0.017 °2θ and an accumulative counting time of 20.32 s/step. The experimental powder diffraction pattern is depicted in Figure 2. The software package HighScore Plus V 3.0d of PANalytical, Almelo, Netherlands, was used to smooth the data, to fit the background and to eliminate the Kα 2 component. The top of smoothed peak method was used to determine the peak positions and intensities of the diffraction peaks.
(Color online) X-ray powder diffraction pattern of the title compound using and CuKα radiation (λ = 1.5418 Å).
Automatic indexing of the experimental XRD pattern was done using DICVOL06 (Boultif and Louër, Reference Boultif and Louër2004).
III. RESULTS
The experimental powder diffraction pattern is depicted in Figure 2. Automatic indexing results obtained by DICVOL06 (Table I) show that the title compound is triclinic with the space group P1 and unit cell parameters: a = 9.986(1) Å, b = 9.158(1) Å, c = 11.200(1) Å, α = 115.08(1), β = 117.41(1), γ = 88.61(1), unit cell volume V = 804.70 Å3, Z = 2. The figures of merits are F 20 = 59.9(0.0108, 31) (Smith and Snyder, Reference Smith and Snyder1979) and M 20 = 24.0 (de Wolff, Reference de Wolff1968). All lines were indexed and are consistent with the P1 space group. Only first two pages of the peak table are presented in the article, the whole Table 1 is available as a supplementary material.
Indexed X-ray powder diffraction data for the title compound, LaC9OH21O12. Only the peaks with I rel of 1 or greater are presented [a = 9.986(1) Å, b = 9.158(1) Å, c = 11.200(1) Å, α = 115.08(1), β = 117.41(1), γ = 88.61(1), unit cell volume V = 804.70 Å3, Z = 2 and space group P1]. All measured lines were indexed. The d-values were calculated using CuKα 1 radiation (λ = 1.5406 Å).
ACKNOWLEDGMENT
This work was supported by the specific university research (MSMT No 20/2014).
SUPPLEMENTAL DATA
The supplementary material for this article can be found at http://www.journals.cambridge.org/PDJ
Chemical Information File (CIF) of the compound is available online.
