Kenneth Emerson

Magnetic properties of the alkanediammonium copper halides

Abstract Powder magnetic susceptibility and magnetization data have been obtained for the remaining, unreported members of the quasi-two-dimensional series [NH 3 (CH 2 ) n NH 3 ] CuX 4 for n =2−10 and X=Cl and Br. Values for J (in-plane), J ′ (out-of-plane) and T c are tabulated for the entire series. An alternation between ferromagnetic and antiferromagnetic behavior for the low temperature phases in the bromine series was found. Several unusual low temperature phases which could not be classified were also seen.

Magnetic susceptibility of ((CH3)3NH)2Cu4Br10, chains of stacked linear tetramers

Abstract ((CH 3 ) 3 NH) 2 Cu 4 Br 10 consists of Cu 4 Br 10 linear tetramers which in turn are stacked to form chains. Powder magnetic susceptibility data have been fitted to a linear tetramer model using an end exchange constant J 1 / k =-180 K and a central exchange constant J 2 / k =-140 K.

EPR investigations of the quasi-two-dimensional eclipsed structures of (NH3(CH2)nNH3)CUCl4 with n = 2, 3, and 4

Abstract Electron paramagnetic resonance linewidth measurements as functions of orientation were made on single crystals of the eclipsed, layered series of compounds (NH 3 (CH 2 ) n NH 3 )CuCl 4 , n = 2, 3, 4, for the temperature range 100 to 333 K. Static spin correlations and antisymmetric exchange contributions are sufficient to explain the orientationally dependent data of the linewidths of the n = 2 and n = 3 compounds of the series, but the n = 4 compound linewidth data require the addition of the secular part of the two-dimensional spin-diffusive effects.

Magnetic properties of two copper (II)‐halide layered perovskites

The magnetic properties of the powdered layered structures of 3‐ammoniumpyridinium tetrabromocuprate(II) and 3‐ammoniumpyridinium tetrachlorocuprate(II) have been studied from 4.2 to 150 K. The data were interpreted using both 1D and 2D series expansions for the Heisenberg model, combined with the appropriate mean‐field corrections, yielding interlayer exchanges with J2h/k values of (−11±2) K for the chloride salt and (−52±7) K for the bromide salt. The intralayer exchange (J1h/k) values were found to be (14±2) K and (20±2.5) K for the chloride and bromide salts, respectively. The new results are compared with previous results for the eclipsed layered structure series NH3(CH2)nNH3CuX4, where X=Br or Cl and n=2, 3, 4, or 5. As the halide‐halide separation distance decreases the transition from magnetic isolation of the layers to a strong interlayer exchange is observed. The new study allows confirmation of the power dependence on the halide‐halide separation.The magnetic properties of the powdered layered structures of 3‐ammoniumpyridinium tetrabromocuprate(II) and 3‐ammoniumpyridinium tetrachlorocuprate(II) have been studied from 4.2 to 150 K. The data were interpreted using both 1D and 2D series expansions for the Heisenberg model, combined with the appropriate mean‐field corrections, yielding interlayer exchanges with J2h/k values of (−11±2) K for the chloride salt and (−52±7) K for the bromide salt. The intralayer exchange (J1h/k) values were found to be (14±2) K and (20±2.5) K for the chloride and bromide salts, respectively. The new results are compared with previous results for the eclipsed layered structure series NH3(CH2)nNH3CuX4, where X=Br or Cl and n=2, 3, 4, or 5. As the halide‐halide separation distance decreases the transition from magnetic isolation of the layers to a strong interlayer exchange is observed. The new study allows confirmation of the power dependence on the halide‐halide separation.

Structure and magnetic studies of bis‐piperidinium tetrachlorocuprate

X‐ray, magnetic susceptibility, and epr investigations of bis‐piperidinium tetrachlorocuprate (C5H10NH2)2CuCl4 indicate that it is a complicated structure of CuCl4= chains and ribbons separated by piperidinium groups and that it exhibits weak antiferromagnetism with J/k approximately −0.8 °K. The space group is Pc and the unit cell data are a=8.218 A, b=16.924 A, c=12.186 A, and β=100.5°. The possibilities of magnetic dimensionality transitions and disordering as a function of temperature are discussed.

Crystal structure of tetrachlorobisd[μ-imidocarbonylchloridato]diboron

AbstractBoron trichloride and mercuric cyanide react slowly to form the title compound, B2N2C2Cl8, which contains a four-membered B2N2 ring with alternating BCl2 and N—CCl2. Crystals are triclinic, space group P

An interpretation of the polarized crystal spectra of Mn(II) and Co(II) in D2h symmetry

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Polarized crystal spectra of the mixed metal salt [(CH3)3NH] MnxCu1−xCl3•2H2O

, a = 6.1198(1), b = 7.4457(3), c = 7.9186(3) Å, α = 117.064(2), β = 106.923, γ = 93.712(2)°, Z = 1, and V = 299.07(2) Å3. The compound has a crystallographic center of symmetry but the metric symmetry is close to the expected mmm.