This dataset contains raw experimental data for the structural, optical, and magnetic characterization of the rocksalt-type double nitride Ca2TaN3, prepared by hot isostatic pressing. The publication based on this dataset is titled "Preparation of Rocksalt-Type Semiconductor Ca2TaN3 via Hot Isostatic Pressing" published in Zeitschrift für anorganische und allgemeine Chemie, 2026. The dataset comprises: (i) room-temperature powder X-ray diffraction data collected on a Stoe & Cie StadiMP diffractometer (Ag-Kα1 radiation, 300 K); (ii) temperature-dependent powder X-ray diffraction patterns recorded during a heating (40–1000 °C) and cooling (980–40 °C) cycle in 20 °C steps; (iii) field- and temperature-dependent magnetization data acquired on a Quantum Design PPMS with VSM option (2–300 K, up to ±5 T); and (iv) a diffuse reflectance UV-Vis spectrum collected on a Jasco V-650 spectrophotometer (190–800 nm). Diffraction data are provided as two-column ASCII files (2θ, intensity); magnetization data as native Quantum Design PPMS binary files; and the UV-Vis spectrum in JCAMP-DX format. The dataset is intended to support Rietveld structure refinement, thermal expansion analysis, magnetic susceptibility modeling, and optical band gap determination.eng