Thermal expansion of phosphate–sulfates of eulytite structure

New phosphate–sulfates of the next chemical formulae ASr₂Eu(PO₄)₂SO₄ (A = K, Rb, Cs), NaBa₆Zr(PO₄)₅SO₄, Pb₂Mg₂(PO₄)₂SO₄, and Ba_xSr_4−x(PO₄)₂SO₄ (0 ≤ x ≤ 4) have been designed and synthesized with the aim of investigating their thermal expansion properties in the low-temperature region. Obtained samples have been characterized with X-ray, IR, DTA, and microprobe electron analyses. Crystal structure and unit cell parameters were derived from the least-squares refinement of powder X-ray diffraction data (eulytite-type, sp. gr. $I4\overline{\text{3}}d$). The magnitudes of average linear thermal expansion coefficients vary from 1.1 × 10⁻⁵ to 1.7 × 10⁻⁵ K⁻¹, which is conducive for application in optics and electronics. Graphical Abstract: .