Tutton Salt Research Articles

Angular overlap model description of the electronic and magnetic properties of copper(II) complexes

The molecular orbital orientation of the angular overlap model has been developed to describe the d-d electronic spectra, anisotropic molecular magnetic susceptibilities, and esr g values of orthorhombically distorted octahedral copper(II) complexes. By systematically varying the σ and π perturbation energy parameters good agreement is reached between the experimental properties and the corresponding calculated values with particular reference to the potassium copper Tutton's salt (KCu(HO)(SO)).

Electron paramagnetic resonance of Mn 2+ in ammonium and potassium-nickel tutton salt single crystals

EPR of Mn 2+ has been studied in nickel ammonium and nickel potassium sulphate hexahydrate at room temperature and at X-band. The spin Hamiltonian analysis is presented. Observed features in the Mn 2+ spectra are explained in terms of magnetic effects of Ni 2+ ions and cross-relaxation between Ni 2+ and Mn 2+ ions.

The Measurement of Anisotropic Magnetic Susceptibilities Using the Faraday Method

Apparatus of the Faraday type to measure crystal magnetic susceptibilities is described in conjunction with the method of analysis to deduce the anisotropic molecular magnetic susceptibilities. The relative merits of the Faraday and torsion methods to measure anisotropic susceptibilities are discussed. The principal molecular susceptibilities* which were determined at 293 K for the cesium, potassium, and ammonium copper Tutton's salts indicate orthorhombic distortion in the crystal fields around the copperion.

Spin-Lattice Relaxation and Cross Relaxation in Nickel Thallium Tutton Salt

Paramagnetic relaxation of single crystal NiTl 2 (SO 4 ) 2 ·6HO 2 O was studied by AC susceptibility measurement in magnetic field of 0∼20 kOe. It was possible to separate experimentally cross relaxation and lattice-bath relaxation from spin-lattice relaxation under appropriate condition. Above λ point of liquid He ( T λ ), spin-lattice relaxation was strongly affected by lattice-bath relaxation and also by cross relaxation. Below T λ , where lattice-bath relaxation was not observed, spin-lattice relaxation did not have such a strong effect of cross relaxation. Concentration dependence of cross relaxation time was also discussed. Cross relaxation time was temperature dependent especially at high magnetic field.

ESR of copper tutton salts around 0.1 K

A remarkable H/ T effect in the intensity of ESR absorption is reported for the case of two Cu Tutton salts studied at 9.4 GHz and at temperatures down to 37 mK. Results can be reasonably expressed by the Brillouin function for S = 1 2 .

Dynamic polarization and cross-relaxation in diluted copper tutton salts

The dynamical polarization of the protons in some diluted copper Tutton salts has been measured in the temperature range from 4.2 K to 20.4 K. In this temperature range the behaviour of the dynamical polarization changes considerably because the hyperfine splitting of the E.S.R. spectrum plays an essential part only at the higher temperatures whereas at 4.2 K the hyperfine splitting has no effect on the dynamical polarization. A theory, based on Provotorov's treatment on cross-relaxation, accounts for this behaviour over the whole temperature range.

Direct and Raman spin-lattice relaxation in Co 2+ salts : II. Cobalt Tutton salts

Spin-lattice relaxation in some cobalt Tutton salts has been studied with the dispersion-absorption technique. Above 4 K a T 9 Raman relaxation process was observed. At liquid-helium temperatures the direct-process spin-lattice relaxation time could be calculated from the observed relaxation time by taking into account the effects of phonon bottleneck and fast relaxation centres. The result for the spin-lattice relaxation time in strong external magnetic fields can be expressed as τ −1 = 0.13 TH 4 + 1.2 × 10 −9 T 9 J 8 ( θ D = 180 K) s −1 ( H in kOe, T in K).

Electron paramagnetic resonance of divalent manganese in cobalt ammonium sulphate hexahydrate

EPR of Mn 2+ has been studied in cobalt ammonium sulphate hexahydrate from ≈ 90°K to ≈ 373°K. The spin-hamiltonian analysis is presented. It is concluded that the coordination of water ligands around the divalent ion is almost the same as that in other Tutton salts.

Hexaaquocopper (II) ions in Tutton's salts

Hexaaquocopper (II) ions in Tutton's salts

Paramagnetic Relaxation in Some Nickel Tutton Salts and Cupric Nitrate Salt

The magnetic field and concentration dependences of the paramagnetic spin relaxation in some nickel tutton salts and a cupric nitrate salt are studied by non-resonant type experiment. A modified Hartshorn bridge operating up to 100 kHz was used inside a high field superconducting magnet of the maximum field of 60 kOe. At temperature region from 4.2 K to 1.5 K, high frequency susceptibilities show that there are several relaxation processes at some special values of magnetic field, of which relaxation times are faster than of usual spinlattice relaxation. The observed relaxation phenomena have been successfully explained by various types of multiple spin flip cross relaxation. The cross relaxation phenomena among unlike spins are also observed in the diluted mixed crystals of (Ni-Mn)-, (Ni-Fe)-, and (Ni-Co)- ammonium tutton salts. Qualitative explanations are given of the anomalous fild dependence of the spin-lattice relaxation time of Co(NH 4 ) 2 · (SO 4 ) 2 ·6H 2 O from the view point of the cross relaxa...

Crystallography of Some Double Sulfates and Chromates.

New information is given on cell parameters, density and methods of preparation of 50 compounds of the langbeinite and Tutton salt groups. The langbeinites have the general formula (A+)2(B2+)2(XO4)3 and the Tutton salts the general formula (A+)2(B2+)(XO4)2 · 6H2O, where A is K, Rb, (NH4), Tl or Cs; B is Mg, Ni, Cu, Co, or Zn; and X is S or Cr. A comprehensive list of references on the crystallography of the compounds is included.

Optical Absorption Spectra of Copper Ammonium Sulphate Hexahydrate Single Crystals Diluted with Magnesium Ammonium Sulphate Hexahydrate

AbstractThe optical absorption study on the effect of solid dilution on tutton salts has been extended to the case of copper ammonium sulphate single crystals diluted with magnesium ammonium sulphate, and the change of crystal field symmetry from tetragonal to rhombic, on dilution, has been established.

Distant endor in diluted copper tutton salts

A theoretical description of the distant ENDOR effect is given, where the strong coupling between the dipole-dipole interaction system and the nuclear Zeeman system is taken into account. This treatment is applied to Cu Tutton salts for which the stationary as well as the transient behaviour of the distant ENDOR effect is calculated. Experiments of distant ENDOR were performed in these salts at 3 kG and liquid-helium temperatures. The results of these measurements are presented and compared with the theory. It appears that the theory gives a good description of these experimental results.

Molecular magnetic ellipsoid in cobalt ammonium Tutton salt

The orientation of the principal molecular axes bears no obvious relationship to the metal–oxygen bond directions in the complex ions of cobalt ammonium Tutton salt. Details of the proof of this phenomenon illustrate important aspects of the experimental measurement and subsequent theoretical treatment of the principal magnetic susceptibilities of monoclinic crystals.

Interionic forces in crystals—II. Infrared spectra of SO4 groups and “octahedrally” coordinated water in some alums, Tutton salts, and the double salts obtained by dehydrating them

Abstract Infrared spectra of 22 alums (including α, β and γ types) show simple v 3 and v 4 sulfate vibrational peaks indicating essentially T d symmetry, plus numerous peaks due to water coordinated about the M''' and M' ions. There are few simple correlations of spectra with change in either cation, but the position of v 3 is slightly affected by change from α to β structure. Infrared spectra of 18 Tutton salts are more sensitive to the nature of the M' cation than to the M'' cation. The effective SO 4 symmetry is C 3 v . Infrared spectra of 24 dehydrated alums fall into two main symmetry patterns for SO 4 , C 3 v , for Al''' and C 2 v , (probably) for other M''' ions. The spectral lines are remarkably sharp and intense, and depend more on the nature of the M''' than on the M' cations. The rock and wag frequencies for waters “octahedrally” coordinated to M''', M'', and M' cations can be systemized in terms of ionic charge and presence or absence of d orbitals in the cation.

Electron spin-lattice relaxation of Cu ++ in zinc ammonium tutton salt

Electron spin-lattice relaxation rates of Cu ++ in Zn(NH 4) 2(SO 4) 2·6H 2O have been measured as a function of temperature and magnetic field. The measurements were carried out for four different concentrations of Cu ++ ions in the samples: 100%, 10%, 1.0% and 0.20%. At approximately 3000 Oe relaxation rates have been observed in the temperature range 1.2 < T < 15 K. At the lower temperatures relaxation rates proportional to T +1 and strongly dependent on the concentration of Cu ++ in the samples have been measured. At the higher temperatures a T 9 dependence has been observed. The relaxation rates in the He temperature range proved to be extremely low. At 2.25 K relaxation rates at non-resonant fields could be measured for 200 < H < 6000 Oe. At the higher fields a H 4 dependence independent on concentration has been observed. At the lower fields a H -1 dependence, strongly influenced by the concentration of Cu ++ occurs. The observed temperature and field dependence can be explained by Kronig-Van Vleck relaxation mechanisms and simultaneous relaxation via pairs of interacting Cu ++ ions.

Forbidden transitions in the infra-red spectra of tetrahedral aniona—VI: Tutton's salts and other double sulphates and selenates

The infra-red spectra of 78 double salts of which 64 are Tutton's salts have been investigated in the region 2000–40 cm−1, and are considered in terms of the site group and factor group approximations. The magnitude of the deviations from the free-ion selection rules is not related to any structural parameter.

The Influence of nonmagnetic impurities on the paramagnetic spin-lattice relaxation in copper tutton salts

Measurements are reported on various copper Tutton salts. The introduction of nonmagnetic impurities on the place of the monovalent cation leads to faster relaxation processes. These faster relaxations are similar to those observed earlier in manganese ammonium Tutton salt when potassium or rubidium was added in the crystal. A satisfactory description of the τ L vs. T, H c curves was given by De Vries et al. 1) on the basis of a model with two magnetic spin systems. In the ‘impurified’ copper Tutton salts such a model may also be used; the fast relaxation processes ascribed to the second spin-systems obey an Orbach type of temperature dependence of the relaxation time: τ L ∞ (exp(Δ/ kT) − 1) with 3K ≤ Δ/ k ≤ 7K. It is suggested that the occurrence of the fast relaxation processes is related to irregularities in the orientation (α, ψ) of the tetragonal symmetry axis in the mixed crystals and to the difference in crystal ionic radii between impurity ions and replaced monovalent cations.

Etude cristallographique des orthofluoroberyllates Me I2Me II(BeF 4) 2·6H 2O

We describe fourteen new orthofluoroberyllates Me I 2Me II(BeF 4) 2·6H 2O, with Me I = K, NH, Rb, Tα or Cs and Me II = Ni, Co, Cu, Zn or Cd, isomorphous with Tutton's salts Me I 2Me II(SO 4) 2·6H 2O : they crystallize in the monoclinic space group P2 1 a . Refinement of the atomic positions in the compounds (NH 4) 2Co(BeF 4) 2·6H 2O and K 2Ni(BeF 4) 2·6H 2O shows evidence for hydrogen bonds between oxygen atoms of water molecules and fluor atoms of BeF 4 groups. Fluor is more electronegative than oxygen : indeed, some distance O—H---F (from 2,59 to 2,85 Å) are slightly smaller than distances O—H---O (from 2,70 to 2,85 Å).

Frequency Dependence of the Paramagnetic Relaxation in a Copper Tutton Salt

Measurements have been made of the paramagnetic relaxation rate of the copper ions in zinc-diluted crystals of copper ammonium sulfate at 1.3\ifmmode^\circ\else\textdegree\fi{}K by a pulsed-microwave technique at frequencies between 9.0 and 11.8 GHz, in order to look for the ${\ensuremath{\nu}}^{4}$ dependence to be expected if the orbit-lattice mechanism and direct process dominate. In the crystals examined, at the highest copper concentration, the rate decreased with increasing frequency. At the lowest concentration, a dependence was obtained which could be fitted with a fourth power, but this behavior was not independent of crystal orientation. A linear temperature dependence of the rate was obtained below 2.1\ifmmode^\circ\else\textdegree\fi{}K.