Surface composition of native gold and Ag/Au alloys

The surface composition of Ag/Au alloys has been studied by X-ray photoelectron spectroscopy (XPS). Surface segregation of Ag is observed, particularly for alloys having low Ag content. The content of Ag in the first surface monolayer is in accordance with data from ion scattering and with a theoretical model for segregation in ordered solutions. The surface of native gold was found to be enriched with silver in the case of mine gold, and the degree of segregation was significantly higher than for an alloy having similar bulk composition. The surface of mine gold taken from an oxidized zone contained less silver than did that of usual mine gold. The surface of placer gold was depleted of silver as compared to the bulk. These data show the surface composition of native gold to differ markedly from that of an alloy having the same bulk Ag content, and to depend on the genesis of the native gold sample.     

Intramolecular cyclization of alkoxycarbonylcarbenes during thermal decomposition of alkyl diazoacetates

Conclusions We were the first to observe the intramolecular cyclization of alkoxycarbonylcarbenes under the conditions for the thermal decomposition of alkyl diazoacetates, which proceeds via the insertion of the carbene C atom in the-C -H bond of the ester group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1652–1654, July, 1979.     

Electronic structures of MRhO2, MRh2O4, RhMO4 and Rh2MO6 on the basis of X-ray spectroscopy and ESCA data

X-ray O Kα, Rh Mγ and a series of M Lα emission spectra, ESCA spectra of the valence and inner levels, and O K and Rh M_III quantum-yield spectra for X-ray photoemission of the rhodium double oxides MRhO₂ (M = Li, Na, K), MRh₂ O₄ (M = Be, Mg, Ca, Sr, Ba, Co, Ni, Cu, Zn, Cd, Pb), RhMO₄ (M = V, Nb, Ta) and Rh₂MO₆ (M = Mo, W) have been measured and the dependence of electronic structure on the metal M analysed. For all compounds the inner part of the valence band corresponds to O 2p_σ + O 2p_π + Rh 4d states, while the outer part corresponds to Rh 4d. The valence band is separated from the conduction band by a narrow gap of width less than 1 eV. The first empty band, near the bottom of the conduction band, is formed by Rh 4d states, followed by a band due to vacant O 2p states.     

Cycloocta- and cyclononadiene and the corresponding triene hydrocarbons from the adducts of mono- and dihalocarbenes to cycloheptene and cyclooctene

Conclusions The thermal dehydrohalogenation of the adducts of mono- and dihalocarbenes to cycloheptene, cyclooctene, or their derivatives, run in either the gas or the liquid (excess of quinoline or N,N-dialkylaniline) phase, is a general method for the preparation of cycloocta- and cyclononadiene, or of the corresponding triene, hydrocarbons.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2608–2610, November, 1971.