Das Spektrum von Praseodymsalzen sauerstoff‐haltiger Säuren

Abstract

PrBr,, 6 H, ; 592.5-594.5 (2) ; 589-591.5 (2); 484-485 (10) ;( 2 ) ; 477.8-479.86); 453-454 (8). AuBerdem sehr geringe Verdunkeliuigen von 470 bis 484 (I) und 45-457 (2), in denen sich die vorerwahnten Linien stark abheben. 471-472.6 (6); 468.6-470 ( 3 ) ; 444.2-448.2 (8). PrJ,. -Vielleicht 2 schwache Linien zwischen 603 und 610; 599.5-600.5 (I): -195.6-496.2 (10); 481.8-482.4 (6); 475.6-476.4 (2); 472-474 (I) ; 456-457 (8) I 455-456 (3). 447.8-450 (5); 443.5-445.8 (4). PrJ,, 6 H,O. -595-597 (7) ; 485-486 (10); 482-483 (4); 473.2-474.2 (6); PrJ,, 9 H,O. -602-603.5 (8) ; 595-596.5 (10) ; 592.5-594 (7). Alle diese Banden sehr scharf, jedoch auch in den Zwischenraumen derselben eine Absorption (4); 489-490. ( I ) ; 484-485 (10) recht scharf; 469.5-472 (7) nicht scharf; 443.6-446.8 (10) venvaschen.PrJ,-Losung (Absorptionsspektrum). -594-597 (2) ; 586-591.5 (4) ;

Preparation of Anhydrous Lanthanon Halides.

“…It is quite likely that the difficulty of the method lies in the inability to obtain pure HBr absolutely free of H20 and 02. In most cases, the anhydrous bromide could be obtained smoothly by heating the hydrated bromide, equilibrated with NH4Br, in a stream of pure, anhydrous HBr (24,25,50,54). The temperature is raised slowly to 250°, where most of the water is expelled, after which the sample is heated slowly to 600°, where the NHJBr is sublimed away completely.…”

“…Anhydrous iodides have been obtained by heating in a stream of HI and H2 the hydrated iodide that has been equilibrated with ammonium iodide (39,49,51). Even this procedure, however, failed to produce pure anhydrous iodides for the heavier lanthanons (24,25,39,52,54). 2.…”

“…Instead of pure HI, the more readily obtainable mixture of H2 and HI normally is used. The transformation occurs at 400-600°and may take as long as 24 hours. Pure Eul3 cannot be obtained by the method (39,56) and extreme care is required to prepare pure Sml3 and Ybl3 (39, 52, 68).…”

L'effet néphélauxétique pour les configurations 4fN en phase solide

“…On a remarqué depuis longtemps que les spectres étaient, en général, dans un solide, déplacés plus ou moins vers le rouge par rapport au spectre d'absorption de l'élément en solution aqueuse. Cet effet, découvert par Ephraïm xen 1926 [1,2], appelé effet néphélauxétique par Jôrgensen est interprété par celui-ci comme dû à une contribution covalente à la liaison chimique supportée par les ions Ln3+ [3,4,5]. L'effet néphélauxétique, bien connu également pour les éléments à électrons d [6], correspond, strictement, à la diminution des valeurs des paramètres de Racah (ou des intégrales de Slater) de la configuration par rapport aux valeurs de l'ion libre.…”

Some properties of some rare-earth and transition metal dihydroxycarboxylates

“…The e f f l u e n t s o l u t i o n was collected i n a s e r i e s of f i f t y -f i v e 1.2 1 f r a c t i o n s and t h e pH of qach s o l u t i o n was measured t o monitor t h e separation achieved. The s t~o n g acid ( H C~) was observed t o pass through t h e system ( a t pH 0.9) i n Tractions 19-36, and 2,3-dihydroxy-2-methylbutanamide was detected (ac-companied by some formic and 2,3-dihydroxy-2-methylbutanoic acids) in fractions 40-49 (which had a pH of about 2.4) .When the HCL-free amide-bearing fractions(40)(41)(42)(43)(44)(45)(46)(47)(48)(49) were combined and evaporated to a small volume (at 9 8 ' ) and allowed to cool, large crystals of 2,3-dihydroxy-2-methylbutanamide separated from the aqueousmedium.The crystals were filtered off, washed with a small portion of cold acetone and dried. The recovered amide, weighing 288 g (86% yield), melted at 139-140' and was found to contain 45.25% C, 8.2% H and 10.5% N (theoretical analysis: 45.11% C; 8.…”