title: 9Mg(OH)(2)·MgCl(2)·4H(2)O, a high temperature phase of the magnesia binder system.
abstract: The metastable phase 9Mg(OH)(2)·MgCl(2)·4H(2)O (9-1-4 phase) was found at the extended metastable isotherm of Mg(OH)(2) in the system MgO-MgCl(2)-H(2)O at 120 °C and occurs as intermediate binder phase during setting of magnesia cement due to temperature development of the setting reaction. The crystal structure of the 9-1-4 phase was solved from high resolution laboratory X-ray powder diffraction data in space group I2/m (C2/m) (a = 22.2832(3) Å, b = 3.13501(4) Å, c = 8.1316(2) Å, β = 97.753(1)°, V = 562.86(2) Å(3), and Z = 1). Structural and characteristical relations of the phases in the system MgO-MgCl(2)-H(2)O can be derived, with which the development of the cement or concrete qualities becomes explainable.
authors.affiliation: Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany. r.dinnebier@fkf.mpg.de
authors.forename: Robert E
authors.initials: RE
authors.lastname: Dinnebier
authors.forename: Daniela
authors.initials: D
authors.lastname: Freyer
authors.forename: Sebastian
authors.initials: S
authors.lastname: Bette
authors.forename: Melanie
authors.initials: M
authors.lastname: Oestreich
mesh_terms: D015636:Magnesium Chloride / Q000737:chemistry*; D008276:Magnesium Hydroxide / Q000737:chemistry*; D008277:Magnesium Oxide / Q000737:chemistry*; D010316:Particle Size; D033362:Powder Diffraction; D012995:Solubility; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D015636:Magnesium Chloride; D014867:Water; D008277:Magnesium Oxide; D008276:Magnesium Hydroxide