Low-Temperature Heat Capacity of Azurite

Forstat, H.; Taylor, G.; King, B. R.

doi:10.1063/1.1730553

Cited by 21 publications

(17 citation statements)

References 6 publications

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“…Our experimental azurite heat capacity data are shown in Fig. 2 a together with the curve of Forstat et al (1959). The curves overlap satisfactorily.…”

Section: Comparison Of Malachite and Azurite Thermochemical Constantssupporting

confidence: 53%

“…To these results for azurite between 3.8-300 K we added the experimental heat capacity data of Forstat et al (1959) (temperatures 1.76-3.6 K) who had observed a 2-shaped anomaly at 1.84K (Fig. 2a).…”

Section: Calculation Of Thermodynamic Data Of Azurite and Malachitementioning

confidence: 99%

“…They showed that at 1.86 K azurite passes from a paramagnetic state to an ant• one. Azurite heat capacity measurements were performed by Forstat et al (1959) with a vacuum calorimeter between 1.7-3.6 K with 0.01-0.02 K spacings. Our experimental azurite heat capacity data are shown in Fig.…”

Section: Comparison Of Malachite and Azurite Thermochemical Constantsmentioning

confidence: 99%

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Thermodynamic properties of copper carbonates ? malachite Cu2(OH)2CO3 and azurite Cu3(OH)2(CO3)2

et al. 1992

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Abstract. The thermodynamic properties of the copper carbonates malachite and azurite have been studied by adiabatic calorimetry, by heat-flux Calvet Calorimetry, by differential thermal analysis (DTA) and by thermogravimetric (TGA) analysis. The heat capacities, C o of natural malachite and azurite have been measured between 3.8 and 300 K by low-temperature adiabatic calorimetry. The heat capacity of azurite exhibits anomalous behavior at low temperatures. At 298.15 K the molar 8298.15 heat capacities C ~ and the third law entropies o are 228.5 _+ 1.4 and 254.4 _+ 3.8 J mol-1 K-1 for azurite and 154.3+0.93 and 166.3• K -1 for malachite. Enthalpies of solution at 973 K in lead borate (2PbO'BzO3) have been measured for heat treated malachite and azurite. The enthalpies of decomposition are 105.1 +__ 5.8 for azurite and 66.1 +_ 5.0 kJ tool-1 for malachite. The enthalpies of formation from oxides of azurite and malachite determined by oxide melt solution calorimetry, are -84.7 + 7.4 and -52.5 __+ 5.9 kJ mol-1, respectively. On the basis of the thermodynamic data obtained, phase relations of azurite and malachite in the system Cu 2 + -HzO-CO2 at 25 and 75 ~ have been studied.

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“…Our experimental azurite heat capacity data are shown in Fig. 2 a together with the curve of Forstat et al (1959). The curves overlap satisfactorily.…”

Section: Comparison Of Malachite and Azurite Thermochemical Constantssupporting

confidence: 53%

Section: Calculation Of Thermodynamic Data Of Azurite and Malachitementioning

confidence: 99%

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Thermodynamic properties of copper carbonates ? malachite Cu2(OH)2CO3 and azurite Cu3(OH)2(CO3)2

et al. 1992

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“…One such material is azurite, Cu 3 (CO 3 ) 2 (OH) 2 , a natural mineral which has been proposed as an experimental realization of the 1D distorted diamond chain model. Interest in the magnetic properties of this material began in the 1950s when an ordered antiferromagnetic (AFM) ground state was observed below 1.9 K. 1,2 From these studies, a detailed description of the magnetic moment structure was never revealed however it has been speculated that the low ordering temperature may result from frustration in the diamond arrangement of spin-1/2 Cu 2+ ions 3 . Early susceptibility measurements indicated that the coupling of spins within the chain could be described with alternating dimers and monomers 4 ( Fig.…”

Section: Introductionmentioning

confidence: 99%

“…2, for example, we see a 30% increase in the intensity of the (120) peak on TABLE I: Positional and thermal parameters of Cu3(CO3)2(OH)2 as obtained from the structure refinements of single-crystal (on both D10 and SXD) and powder data in the monoclinic space groups P 21/c. The isotropic thermal parameters Uis are given in units of 100Å 2 . For the refinement several thermal parameters were constrained to be equal.…”

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confidence: 99%

Magnetic and crystal structure of azurite Cu3(CO3)<

et al. 2011

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Here we present neutron diffraction results on the mineral azurite. We have found that the crystal structure of azurite can be described in the space group P 21 which is the next lower symmetric group of P 21/c as found in earlier works. This small change in symmetry does not greatly influence the lattice parameters or atomic fractional coordinates which are presented here for single crystal diffraction refinements. The ordered magnetic moment structure of this material has been determined and is comprised of two inequivalent magnetic moments on copper sites of magnitude 0.684 (14) and 0.264(16) µB. This result is discussed in terms of the anisotropic exchange and DzyaloshinskiiMoriya interactions. It is found that the system is likely governed by one-dimensional behaviour despite the long-range ordered ground state. We also highlight the significance of strain in this material which is strongly coupled to the magnetism.

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The magnetic behaviour of azurite

Frikkee¹,

Handel²

1962

Physica

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Low-Temperature Heat Capacity of Azurite

Cited by 21 publications

References 6 publications

Thermodynamic properties of copper carbonates ? malachite Cu2(OH)2CO3 and azurite Cu3(OH)2(CO3)2

Thermodynamic properties of copper carbonates ? malachite Cu2(OH)2CO3 and azurite Cu3(OH)2(CO3)2

Magnetic and crystal structure of azurite Cu3(CO3)<

The magnetic behaviour of azurite

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