Comparative Data for Hydrogenselenites

X-ray diffraction results show that the compounds are isostructural and monoclinic with the possible space group P2i-C (No. 4) or P2i/m-Cih (No. 11) and Z = 4. The following lattice parameters are given for MH(Se03)2 2.5H20  

For the indexed powder diagram of YH(Se03)2 2.5H20, see the table in the original paper, Immonen et al. [2]. Interplanar spacings and line intensities of the powder diagram of the isomorphous La and Ce compounds and the isomorphous compounds with M = Y, Prto Lu are given by [3]. 

The IR spectra of MH(Se03)2 2.5H20 with M = Eu and Dy to Lu, MH(Se03)2 2H20 with M = Y, Pr, Nd, Sm, Gd, and Tb, and MH((Se03)2 with M = La, Ce were studied. The following IR bands (in cm ) are recorded on Nujol mulls between rocksalt plates  

The group with M = La and Ce is different from the others and shows a considerable shift of the bands corresponding to the selenous acid. The IR spectra for LaH(Se03)2 and for TbH(Se03)2 2H20 are given in the paper, Giesbrecht et al. [3]. 

The coordination number of the Pr ion is nine. Six 0(86205) and three OiSeO ) form a  

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