A series of gallium-substituted 4CaO·3Al 2 O 3 ·3H 2 O-cement phase analogues: X-ray powder diffraction and IR spectroscopy studies

The solid solution series 4CaO·3Al 2 O 3 ·3H 2 O – 4CaO·3Ga 2 O 3 ·3H 2 O was synthesised by means of hydrothermal treatment. The products were characterised by X-ray powder diffraction and Fourier-transform infrared spectroscopy. No miscibility gaps were observed. All products are orthorhombic, having space group Aema . The main structural change due to the substitution of Ga for Al is an increase in the average T –O bond length and the lattice parameters. The coordination of Ca by oxygen is only slightly affected. The increase in the T –O bond lengths is compensated for by a decrease of the inter-tetrahedra angles, leading to an adaptation of the layer-geometry to the coordinational needs of Ca.