Studies on the mechanism of reaction leading to AlVMoO7 have been made using X-ray diffraction and infrared spectroscopy. The XRD study of the process was carried out in a high-temperature X-ray attachment. The AlVMoO7 phase can be synthesized by two methods, The investigations lead to the conclusion that both reactions run through a stage in which Al-2(MoO4)(3) is involved. The IR spectra of the AlVMoO7 and of samples after selected stages of the synthesis reaction are given. The diffraction pattern of AlVMoO7 was indexed. The phase crystallizes in an orthorhombic system with the unit cell parameters : alpha = 0.53826(11) nm, b = 0.81771(11) nm, c = 1.27493(20) nm.