M. A. Bredig

Significance of both polarizability and polarizing power of cations in nitrate vibrational spectra

Vibrational frequencies of the NO3− ion in matrix‐isolated monomers of several nitrates MNO3 are shown to correlate with the polarizing power of the cation M+, P≡ (z/r)/Seff, properly defined as the quotient, rather than the product, of the ionic potential, z/r, and a factor Seff= (5z1.27)/(r(1/2)I) (Ahrens, 1954) representing the efficiency with which the electron shell of the cation screens its nuclear charge. For molten nitrates MNO3, this correlation breaks down: in the condensed state, the polarizability of the cation, a, becomes important as the result of the mutual enhancement of the polarization of a given cation by several anions. A correlation of ν1 with the product of cation polarizing power and polarizability, P a, is presented.

Thermochemical Decomposition of Water Based on Reactions of Chromium and Barium Compounds

A potentially useful thermochemical cycle developed for the production of hydrogen and oxygen from water consists of three chemical reactions that take place in the temperature range from 400� to 1200� K. The oxidation and reduction of chromium compounds by barium hydroxide and the hydrolytic disproportionation of barium chromate(IV) and barium chromate(V), the reactions which constitute the proposed cycle, have been demonstrated.

Electrical Conductance of Solutions of Salts in Liquid Metals. Potassium Iodide in Potassium

The electrical conductivity of KI-K solutions at 700 deg C is measured for 0 to 100% K concentration. The properties of KI-rich and K-rich solutions are discussed. (T.F.H.)

A mixed-valency lead oxyiodide

A new, mixed-valency lead oxyiodide of variable composition, Pb(II)4−x Pb(IV)xO4O2x, has been synthesized by different routes and identified by X-ray diffraction. The reaction of massicot (yellow, orthohombic PbO) with I2 and water at room temperature produced a brown powder which consisted of crystals of almost colloidal dimensions with the above stoichiometry where 1<x<2. The crystals appear to have body-centered tetragonal symmetry with a0 = 4.10 and c0 = 13.6 A. The reaction of PbI2 and Pb3O4 at 500°C produced better crystallized specimens most likely with similar stoichiometry, Pb4O4I2 but always mixed with a considerable amount of at least one other phase, e.g. Pb(II)5O4I2( = “4PbO·PbI2”). The reaction of PbO2 with PbI2 in the temperature range of 430–550°C produced crystallized specimens with higher iodine content, e.g. Pb(II)2.5Pb(IV)1.5O4I3 (or 32 < × <2 in the above general formula), while an oxyiodide with the ideal composition, Pb(II)2Pb(IV)2O4I4 = 4PbOI (corresponding to BiOI) was never obtained. Some general reactions of the above compounds are described.

The born-einstein letters.

Wilcox et al. (1 3 Apr., p. 185), show a convincing relation between the solar magnetic sector structure and the earths meteorological activity as indicated by vorticity at the 300-millibar level. Is it possible that this interesting correlation may in some way be related to Marksons observation (1) that there is a maximum in thunderstorm activity when the earth is at the leading edge of a negative solar structure? B. VONNEGUT Atinospheric Sciences Research Center, State University of New York, Albany 12222

Two new copper(II) hydroxoiodides

Abstract As evidenced by X-ray diffraction, two new hydroxoiodides of copper have been synthesized and their compositions were deduced from analytical data of their mixtures. One of the compounds, with Cu/I = 4 represented by the formula Cu 4 (OH) 7 I(2.5H 2 O), had a fcc structure with a = 9.43 A and the other with Cu/I = 2.5, represented by Cu(OH) 1.4 (O) 0.2 (I) 0.1 (I 3 0.1 (0.74H 2 O) appeared to have a hexagonal (or pseudo-hexagonal) structure with a = 3.78 and c = 6.61 A . The newly found Cu(II) hydroxoiodides constitute, together with Cu 2 (OH) 3 I, the only known instances in which the ions Cu(II) and I − are present in compounds.