[en] Nonlinear optical (NLO) crystals CoTeMoO_6 have been grown from high temperature solution by means of spontaneous crystallization. These crystals have been characterized by temperature-dependent X-ray diffraction, infrared and electron absorption methods. Moreover, polarized Raman spectra have been measured at room temperature. These studies showed that the Mo"6"+ and Te"4"+ ions are in asymmetric coordination environment, and CoTeMoO_6 has the largest flexibility index among MTeMoO_6 family of telluro-molybdates (M=Zn, Mg, Cd, Mn, Co), making this compound attractive NLO material. Raman and IR studies allowed assigning the observed modes to respective motions of atoms in the unit cell. They have also showed evidence for spin–phonon coupling at low temperatures and suggested that CoTeMoO_6 is prospective material for solid-state Raman laser-frequency converters. Analysis of electron absorption data has shown that Co"2"+ ions are located in sites of weak crystal field with the crystal field parameters Dq and B equal to 548 cm"−"1 and 882 cm"−"1, respectively. - Graphical abstract: View of CoTeMoO_6 crystal structure along the b-axis. - Highlights: • Single crystals of nonlinear optical telluromolybdate CoTeMoO_6 were grown. • Crystal structure was solved by means of single crystal X-ray diffraction. • Raman and IR spectra were measured and analyzed. • Crystal field strength acting on Co"2"+ ions was established from analysis of electron absorption spectra