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Scheelite related compounds (A′,A″)_n[(B′,B″)O₄]_m with B′, B″ = W and/or Mo are promising new materials for red phosphors in pc-WLEDs (phosphor-converted white-light-emitting-diode) and solid-state lasers. Cation substitution in CaMoO₄ of Ca²⁺ by the combination of Na⁺ and Eu³⁺, with the creation of A cation vacancies, has been investigated as a factor for controlling the scheelite-type structure and the luminescent properties. Na₅Eu(MoO₄)₄ and Na_xEu³⁺_(2–x)/3□_(1–2x)/3MoO₄ (0.138 ≤ x ≤ 0.5) phases with a scheelite-type structure were synthesized by the solid state method; their structural characteristics were investigated using transmission electron microscopy. Contrary to powder synchrotron X-ray diffraction before, the study by electron diffraction and high resolution transmission electron microscopy in this paper revealed that Na_0.286Eu_0.571MoO₄ has a (3 + 2)D incommensurately …