Characteristics and Structure of Hopeite-Mineral (Type A3(PO4)2.4H2O)

Aji Syailendra Ubaidillah, Lutfian Rusdi Daryono, Arifudin Idrus, I Wayan Warmada, Karsten Knorr


The aim of the study was to gain more information about the structural changes during the dewatering reactions of the above compounds. The paper is focus on the low-temperature absorption of hopeite clay mineral, afterward the phases are examined for the dependence of temperature at different pressures. Hopeite shows signs of a phase transformation. Their use for the dental cement industry as a lubricant for cold-rolling mills is to be emphasized, such as coating with phosphate mineral or carbonaceous crystal. This is shown by the appearance of the new reflexes. The observed changes take place below the dewatering known from the literature. The phase change was investigated using a neutron scattering experiment. A temperature-pressure phase diagram of the dewatering could be set up in the range of 275 K to 380 K and 10-3 mBar to 103 mBar with the temperature-dependent powder diffractometer at different pressures and the temperature-dependent neutron scattering experiment. In this work, it has been proved that the dewatering of the hopeite is dependent on pressure and that the dewatering process of the hopeite is a reversible process.

Full Text:



Calvo C. (1963), The Crystal Structure of ɤ- Zn3(PO4)2, Phys. Chem. Solids, 24, 141.

Calvo C. (1965), The Crystal Structure of ɤ- Zn3(PO4)2, Can. J. Chem. 43, 436.

Hill R.J. and Jones J.B (1976), The Crystal Structure of Hopeit, Am. Mineral., 61, 987-995.

JCPDS - PC – PDF von ICDD, International Center of Diffraktion Data, Version 2.14.

Kleber. Bautch. Bohm (1990). Einführung in die Kristallographie, 17.Aufl., Verlag Technik Berlin. München.

Liebau F. (1962), Über die Struktur des Hopeits, Chem. D. Erde, 22, 430.

Mamedow, C.S. Gamidow, R.G, und Below N.W. (1961), Crystal Structure of Hopeit, Zn3(PO4)2.4H2O, Kristallogr. 6, 144 (russ).

Rietveld R.M. (1967), Line Profile of Neutron Powder Diffraction Peaks for Structure Refinement, Acta Cryst. 22, 155-152.

Shchegrov L.N. (1986), Thermolylis of Orthorombic Hopeit, Zn3(PO4)2.4H2O, Ukrainian Agricultural Acadeny. Translated from Izvestya Academy Nauk SSSR, Neorganeski Materialy, vol. 22, No.1, PP.157-159, Original Article Submitted May 29th, 1984.

Stephens J.S., and Calvo C. (1967), The Crystal Structure of β- Zn3(PO4)2, Can. J. Chem. 45, 2303.

Touloukian Y.s., Kirby R.K., Taylor R.E., Lee T.Y.R.(1975), Thermal Expansion Metallic Elements and Alloy (1975), Vol.13 of ThermoPhysical Properties of Mater, pp.154-162, New York Washington.

Wolve C.W.(1940), Clasification of Minerals of The Type A3(XO4)2.nH2O, Amer. Miner., 25,787.

Whitker A. (1975), The Crystal Structure Of Hopeit, Zn3(PO4)2.4H2O, Acta Cryst. B31, 2026.

Wilson A.J.C. (1992), International Tables Of Crystalofraphie, (Mathematical, Physical and Chemical Tables), Volume C.



  • There are currently no refbacks.

Creative Commons License
This work is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.