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In this work, we report the room-temperature synthesis of pure calcium tungstate (CaWO 4 ) and copper-doped calcium tungstate solid solution (Ca 0.99 Cu 0.01 WO 4 ) by using a sonochemistry method. These materials were structurally characterized by X-ray diffraction (XRD) and Raman spectroscopy. The obtained XRD patterns were submitted to a Rietveld refinement showing, in both materials, a tetragonal phase with space group and point group of I 4 1 /a and C 4 h 6 , respectively. Microscopy images of both materials, obtained by field emission scanning electron microscopy, showed spherical agglomerated structures composed by spherical nanoparticles, while calcium and tungstate elements were identified by energy-dispersive X-ray spectroscopy for pure calcium tungstate and copper, calcium, and tungstate for Ca 0.99 Cu 0.01 WO 4 solid solution. The decrease of optical band gap ( E gap ) from 4.0 eV (CaWO 4 ) to 3.45 eV (Ca 0.99 Cu 0.01 WO 4 ) confirmed the substitution of calcium atoms for copper atoms in the clusters [CaO 8 ]. Maximum photoluminescence (PL) emission was shifted from 522 nm in the pure CaWO 4 to 475 nm in the Ca 0.99 Cu 0.01 WO 4 solid solution. Consequently, there was an increase of PL emissions intensity in the blue and green regions of the visible spectrum, due to electronic transitions between the orbitals O 2p, Cu 3d, and W 5d.