{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T15:02:25Z","timestamp":1790002945211,"version":"4.0.1"},"reference-count":24,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T00:00:00Z","timestamp":1789603200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Ettringite (Ca6[Al(OH)6]2(SO4)3\u22c526H2O) is an important hydration product involved in the immobilization of oxyanion contaminants in cementitious systems; however, the structural effects of arsenate(V) and chromate(VI) incorporation remain poorly understood. This study investigates the influence of both oxyanions on the formation and structure of ettringite-based materials using X-ray diffraction (XRD) with Rietveld refinement and Fourier-transform infrared spectroscopy (FT-IR). Ettringite remained the dominant crystalline phase in all samples, with no detectable secondary crystalline compounds. Chromate incorporation caused only minor changes in lattice parameters, whereas arsenate addition resulted in a decrease in unit cell volume, mainly due to contraction along the c axis. FT-IR analysis confirmed preservation of the ettringite framework and revealed local structural modifications, particularly for arsenate-bearing samples. The results indicate that the presence of both oxyanions is associated with structural changes in ettringite-bearing materials, with arsenate causing a stronger structural response within the investigated compositional range.<\/jats:p>","DOI":"10.3390\/molecules31183305","type":"journal-article","created":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T14:12:09Z","timestamp":1789999929000},"page":"3305","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Structural Characterization of Ettringite Synthesized in the Presence of Arsenate(V) and Chromate(VI) Ions"],"prefix":"10.3390","volume":"31","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6071-4035","authenticated-orcid":false,"given":"Magdalena","family":"Kr\u00f3l","sequence":"first","affiliation":[{"name":"Faculty of Materials Science and Ceramics, AGH University of Krakow, 30 Mickiewicza Av., 30-059 Krak\u00f3w, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Witold","family":"Jastrz\u0119bski","sequence":"additional","affiliation":[{"name":"Faculty of Materials Science and Ceramics, AGH University of Krakow, 30 Mickiewicza Av., 30-059 Krak\u00f3w, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"W\u0142odzimierz","family":"Mozgawa","sequence":"additional","affiliation":[{"name":"Faculty of Materials Science and Ceramics, AGH University of Krakow, 30 Mickiewicza Av., 30-059 Krak\u00f3w, Poland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1016\/j.molstruc.2015.06.075","article-title":"Structural and spectroscopic characterization of ettringite mineral\u2014Combined DFT and experimental study","volume":"1100","author":"Tunega","year":"2015","journal-title":"J. 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