Anomalous Valence and Periodicity Within the Rare Earth Group.

Abstract

Recently, however, certain earths have been found to possess very well developed "anomalous" valences. A stimulus, supplied by such important discoveries, appears to have been given to the work of prediction, verifica-121 CHEMICAL REVIEWS, VOL. 16, NO. 2 pressed the belief that lanthanum oxide does not absorb oxygen unless cerium is present. Marc (67) and Meyer and Koss (78) also commented on the catalytic effect of cerium on the absorption of oxygen by lanthanum oxides. On the other hand, early work by Cleve ( 22)-probably with impure materials-tended to show that La203 absorbed oxygen at red heat.Higher sulfides have been prepared by Biltz (5), and by Klemm, Meisel, and von Vogel (55). The first investigator prepared LaS2 by heating the sulfate in a stream of hydrogen sulfide. At temperatures above 600°C. the compound breaks down, giving La2S3 and S. It yields hydrogen persulfide with acids and apparently has the structure La2S3 S and is a "polysulfide." These results would seem to be confirmed by the magnetic susceptibility measurements of Klemm, Meisel, and von Vogel, whose data show that no increase in valence occurred during the reaction.The work of Andrieux (1) has shown the existence of borides of lanthanum and other earths having the well-defined formulas MBs. These were prepared by the electrolysis of fused borate and fluoride mixtures in graphite crucibles. These compounds, like the various aluminides, stan-

Notes

“…Recently the preparation of certain acetylenic alcohols by the action of ethylene oxide on acetylenic Grignard reagents hasbeen reported. 1,2 We can now report in a quantitative manner the products obtained from this reaction.…”

“…( 1) Compound (I) loses practically no ammonia upon standing for four months over concentrated sulfuric acid in vacuo and at room temperature. (2) If the pressure in a tube containing some (I) is reduced to less than 1 mm. and the tube, still attached to the vacuum line, is immersed in a bath whose temperature may be controlled, a vigorous reaction ensues at 120 =*= 10°.…”

Συμβολη Εις Την Μελετην Της Χημειας Των Στοιχειων Της Ομαδος Των Σπανιων Γαιων

“…Ό κανών τοϋ Hund, της μεγίστης πολλαπλότητος spin^, προβλέπει δτι ta ασ\)ζευκτα 4f -ηλεκτρόνια εις τα όποια οφείλεται ή παραμαγνητική συμπεριφορά πρέπει να αυξάνουν κανονικώς από εν εις το Ce (III) είς επτά εις το Gd (III), και εν συνεχεία να ελαττοΰνται κανονικώς μέχρις ενός είς το Yb(III). Κατ' αυτόν τον τρόπον τήν μεγίστην μόνιμον μαγνητικήν ρο πήν θα έπρεπε να ε/η το Gd (III), έχον τήν διάταξιν 4f 7 . Τα δεδομέναδμως τοϋ πίνακος 3 δεικνύουν δτι ή μεγίστη μαγνητική ροπή εμφανίζεται ε'ις το Dy (III) και Ho (III), και δτι αντί ενός εμφανίζονται δυο μέγιστα.…”