Experimental and theoretical crystal-chemistry dataset of bulk orpiment As2S3

The present dataset contains the results of the analysis of crystalline As2S3, whose mineralogical name is orpiment. The data were obtained from experimental characterisation of a natural sample of very high purity, and corroborated by ab initio Density Functional Theory (DFT) simulations. The dataset is organised as follows: 1) the Experimental folder contains the results from: a. Environmental Scanning Electron Microscopy ('ESEM' folder) imaging of the exfoliated sample, with several pictures of the sample; b. Confocal Raman microspectrometry ('Raman' folder), whose data comprises images of the samples and the associated spectra in text format (each spectrum has a second file that describes the conditions of its acquisition); c. X-ray diffraction ('XRD' folder), which contains the diffractogram collected for the powdered sample; 2) the Theoretical folder contains: a. the CIF files (Crystallographic Interchange Format) of the orpiment model optimized within the HSE06-D3 and B3LYP-D3 approaches; b. the Raman and infrared spectra calculated at the B3LYP-D3 level of theory; c. the electronic band structure of the mineral obtained with the HSE06-D3 method, with a Python3 script that was used to create the image reported in the folder; d. the elastic moduli in Voigt's notation and the mineral density in kg/m^3 of orpiment calculated using the B3LYP-D3 approach. The experiments were carried out using: - a Thermo Fisher Quattro S ESEM with field-emission gun (FEG) source, equipped with low-vacuum secondary electrons detector, angular back-scattered electron detector and energy dispersive spectroscopy (EDS) X-ray microanalysis; - a WITec Alpha 300 confocal Raman micro-spectrometer equipped with 532 nm and 785 nm lasers; - a Philips PW 1710 X-ray diffractometer (XRD). Theoretical simulations were performed using the CRYSTAL23 code (https://www.crystal.unito.it).