The synthesis of sodalite from aluminium hydroxide, aluminium isopropoxide and pseudo-boehmite (Catapal alumina) as the source of Al, and fumed silica and sodium silicoglycolate (Na-Si^V) as the source of Si has been monitored by solid-state NMR, X-ray diffraction (XRD) and IR spectroscopy. The use of Na-Si^V does not affect the crystallization time, but considerably shortens the preparation of the synthesis gel. Aluminium is not significantly incorporated into the sodalite structure when Al(OH)₃ is used. Pseudo-boehmite gives multi-phasic products in which purely siliceous sodalite is always accompanied by (Si,Al)-sodalites. Some of the Al occupies non-framework positions, and parent gels with Si : Al = 5.0, 2.0 and 1.0 gave solids with Al^IV : Al^VI= 0.73, 1.3 and 3.0, respectively. Only aluminium isopropoxide leads to phase-pure products in which all the AI is four-coordinate and Si : Al = 3.49 and 3.13 with fumed silica and Na-Si^V, respectively. The formula N_AI= 51.855 – 0.0465v_as(Si—O—T) allows the Si : Al ratio to be calculated directly from the FTIR spectrum. With the exception of the material with Si : Al = 1.0 and a₀= 8.94 ± 0.1 Å, the unit cell parameter of sodalites is 8.83 ± 0.1Å irrespective of the Al content.