New series of anhydrous double nitrate salts of the lanthanides. Structural and spectral characterization

Abstract

Anhydrous double nitrates of the lanthanides with potassium have been obtained in crystalline form. Crystallographic and spectroscopic studies are reported. K3Pr2(N03)9 is cubic, with a = 13.52 (1) A and space group 06-/>4332. The experimental density is 2.53 (3) g cm"3 and the computed value is 2.57 (1) g cm"3 for four formula weights. The structure was solved with 529 independent reflections recorded with an automatic diffractometer utilizing the -2 scan method. A least-squares refinement based on all reflections and with isotropic temperature factors for all atoms gave R = 0.058. Each Pr atom is surrounded by twelve oxygen atoms belonging to six nitrate groups which form a distorted icosahedron. The nitrates form two nonequivalent sets, each with its distinct bonding characteristics to the Pr and K atoms. Infrared and Raman studies confirm a strong interaction between the oxygen atoms and the lanthanide ion and indicate typical bidentate bonding. The optical spectrum of K3Nd2(N03)9 was investigated at ambient and at high pressure. The enhancement of hypersensitive transitions was noted and discussed in comparison to other crystals in which the Nd3+ exists in low site symmetries.

Optical Spectra of Neodymium and Europium Tungstates and Molybdates

“…In dimeric carboxylates Nd2 Ala2 (Η2 O)4 they are equal to 2. f o r 4 l 9 / 2 -4 G 5 / 2 , 2 G 7 / 2 a r e e q u a l t o 1 2 3 7 x 1 0-8 and 3885 x 10 -8 , respectively (Table I). The intensities of 4 Ι9/2 -ł 4G5/2, 2G7/2 transitions in the neodymium tungstate spectra are comparable to those observed in DMF solution of lanthanide nitrates [9], explained by polarizability mechanism of Mason [14], and are little higher than those found for lanthanide nitrate [15].…”

The Structure of (NO)2[Ho(NO3)5], A 10-Coordinate Species

“…and they agree with values found in literature (14). A recent report (15) showed that a compound K2Er(N0,),, prepared in a molten salt medium, is monoclinic with a = 7.93, b = 11.92, c = 14.26 A, and P = 102.8". These data are similar to those of (NO),Ho(NO,), and therefore indicate that the two compounds are isomorphous.…”

<b>PREPARATION, SPECTROSCOPIC STUDIES AND X-RAY STRUCTURE OF HOMOBINUCLEAR LANTHANIDE(III) COMPLEXES DERIVED FROM 2,6-DIFORMYL-4-CHLOROPHÉNOL-BIS-(2'-HYDROXY-BENZOYLHYDRAZONE)</b>

“…The bands at 3200 cm -1 characteristic of the H-N vibration are indicative of the non-iminolisation of the amide groups. The broad band of medium intensity occurring in the range 3500-3400 cm -1 not affected by metal coordination is due to the O-H stretching vibration of the phenolic groups and the non-coordinated water molecules [14]. No characteristic band of coordinated water molecules was observed.…”