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Abstract Solid solution of Ca 10.5–1.5 x Yb x (PO 4) 7 (0 ≤ x ≤ 1) was synthesized in the β -Са 3 (РО 4) 2 -type structure by a standard solid-state method. Second-harmonic generation, differential scanning calorimetry, and dielectric measurements showed the presence of a reversible first-order phase transition of ferroelectric type between the room-temperature polar R 3 c structure to centrosymmetry. The temperature of the phase transition decreases from 1203 K for x = 0 to 788 K for x = 1, while the second-harmonic generation response decreases from 1.4 to 0.17 α-SiO 2 powder standard units. The luminescence spectra of Ca 10.5–1.5 x Yb x (PO 4) 7 point to two structural Yb3+ positions in full agreement with the structural data. The intensity of the luminescence emission line at ∼975 nm due to the 2F 5/2 → 2F 7/2 transition reaches the maximum at x = 0.667 in Ca 10.5–1.5 x Yb x (PO 4) 7. The Yb3+ luminescence spectra studied as a function of the chemical composition 0 < x ≤ 1 are compared with the corresponding crystallographic data obtained from the powder diffraction of both X-Ray and synchrotron radiation. Although the overwhelming majority of the Yb3+ cations are located in the pseudosymmetry in M 5 position, their smaller number is located in an acentric manner in M 1 and M 2. A structural mechanism for the transition between the polar (ferroelectric, space group R 3 c) and centrosymmetric (paraelectric, space group R- 3 c) phases is proposed. Graphical abstract Image 1 Highlights • Whitlockite-type Ca 10.5–1.5 x Yb x (PO 4) 7 (0 < x ≤ 1) phosphates were designed. • There is reversible ferroelectric phase transition in temperature range 788–1203 K have been found. • Ca 10.5–1.5 x Yb x (PO 4) 7 exhibit intense broad bands luminescence in the NIR range. • This work provides exploration Ca 10.5–1.5 x Yb x (PO 4) 7 for medicine applications laser materials. [ABSTRACT FROM AUTHOR]