No abstract available

[en] Following previous practice in this series, this review treats comprehensively the coordination chemistry of zirconium and hafnium. The solid-state chemistry of these elements is treated selectively, and organometallic compounds are included only when the compounds contain bonds to elements other than carbon. The present review covers the major journals for the 1983 calendar year and the lesser known and/or foreign journals for the period covered by Chemical Abstracts, Volume 97, Number 21 through Volume 99, Number 24. The major classification is on oxidation states of zirconium and hafnium. An additional section deals with compounds with metal-metal bonds. 81 refs

[en] Following previous practice in this series, this review treats comprehensively the coordination chemistry of zirconium and hafnium; organometallic and solid-state aspects of the chemistry of these elements are treated selectively, the major classification being by oxidation state of zirconium and hafnium. The present review covers the major journals for the 1982 calendar year and the lesser known and/or foreign journals for the period covered by Chemical Abstracts, Volume 95, Number 19 through Volume 97, Number 20. 198 refs.; 5 figs

[en] Interaction of bromine with Zr and Hf dibenzoylmethane (DBM) compounds of following type: (DBM)₄M, CpM(DBM)₃ and Cp₂M(DBM)₂ leads to the formation of (DBM)₂MBr₂, (DBM)₃MBr and CpZr(DBM)₂Br in the rations which depend on the conditions of the reaction (Cp=C₅H₅)

[en] Published in summary form only

No abstract available

[en] Measurements of the London magnetic moment generated in rotating heavy-fermion supercon- ductors are presented. The magnitude of the London moment is found to be identical to that of conventional superconductor, as well as that of high-T_c superconductors, within the experimental resolution of 5%endash 10%. copyright 1996 American Institute of Physics

[en] In continuation of our recent studies on the reactivity of ((Cp*Nb)₂ B₄ H₁₀ O), I with metal carbonyls, we have carried out its reactivity with (Fe₂ (CO)₉) that led to the formation of ((Cp*Nb)₂ B₂ H₄ O(H₂ Fe₂ (CO)₆ BH)), 1. Compound 1 is a heterometallic boride cluster in which (Nb₂ Fe₂)) core describes a butterfly framework with one boron atom lying in a semi-interstitial position. Further, in an attempt to isolate the heterometallic metallaboranes of group 4, we have performed the thermolysis reaction of (Cp₂ Hf(BH₄)₂) with (Cp*IrB₃ H₉) that led to the formation of arachno-((Cp₂ Hf)(Cp*Ir)B₃ H₉)), 2, analogous to ((Cp₂ Zr)(Cp*Ir)B₃ H₉). Compounds 1 and 2 have been characterized by mass spectrometry, ¹H, ¹¹B and ¹³C NMR spectroscopy and the structural types were unequivocally established by crystallographic analysis. (author)

[en] The extraction chromatographic behaviors of zirconium(IV) and hafnium(IV) were investigated using dibenzyl sulfoxide (DBSO) and petroleum sulfoxide (PSO) as stationary phases in the media of hydrochloric acid and hydrochloric acid-ammonium thiocyanate by the batch method. In both systems, Zr(IV) and Hf(IV) showed almost the same behavior at higher HCl concentration due to the formation of halo metal acids, H₂ZrCl₆ and H₂HfCl₆. In the PSO-HCl-NH₄SCN system, the distribution ratios of Zr(IV) and Hf(IV) gave greater values, owing to the formation of ZrO(SCN)₂ and HfO(SCN)₂ at a lower HCl concentration and a decrease along with an increase in the HCl concentration; such phenomena were not observed in the DBSO-HCl-NH₄SCN system. The IR spectra of the extracted complexes gave evidence of oxygen in an SO group coordinating Zr(IV) or Hf(IV) to form extractable species. Finally, a quantitative separation of Zr(IV) and Hf(IV) was achieved using a PSO-extraction chromatographic column (φ6x220 mm) at 25degC. (author)

[en] Phase equilibria in the ternary system Hf-Al-N are investigated. At 1273 K, the ternary phase Hf₃AlN coexists with HfNsub(1-x,) AlN, Hf₂Al₃, HfAl, Hf₄Al₃, Hf₃Al₂ and α-Hf(s.s.). At 1673 K, a second ternary phase Hf₅Al₃N occurs. AlN in contact with hafnium or hafnium-rich Hf-Al alloys decomposes at this temperature into HfNsub(1-x) and HfAl₂. No ternary solubilities are observed further to the extended solid solutions of α-Hf. (orig./RK)