{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T18:08:15Z","timestamp":1785434895884,"version":"3.56.0"},"reference-count":45,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2026,5,12]],"date-time":"2026-05-12T00:00:00Z","timestamp":1778544000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003458","name":"Guizhou Normal University Academic New Talent Fund","doi-asserted-by":"publisher","award":["GZNUD [2025] 10"],"award-info":[{"award-number":["GZNUD [2025] 10"]}],"id":[{"id":"10.13039\/501100003458","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100003458","name":"Guizhou Normal University Academic New Talent Fund","doi-asserted-by":"publisher","award":["GZNUD [2025] 12"],"award-info":[{"award-number":["GZNUD [2025] 12"]}],"id":[{"id":"10.13039\/501100003458","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Guizhou Provincial Science and Technology Projects","award":["QKHJC-ZD [2026] 149"],"award-info":[{"award-number":["QKHJC-ZD [2026] 149"]}]},{"name":"Guizhou Provincial Science and Technology Projects","award":["QKHJC-ZK [2022] YB567"],"award-info":[{"award-number":["QKHJC-ZK [2022] YB567"]}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["42274137"],"award-info":[{"award-number":["42274137"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"award":["42274137"],"award-info":[{"award-number":["42274137"]}],"id":[{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>The structural and electrical transport properties of brucite [Mg(OH)2] were investigated by virtue of in situ Raman spectroscopy and alternating-current impedance spectroscopy under conditions of 0.5\u201320.2 GPa, 298\u2013873 K, and different hydrostatic environments using a diamond anvil cell (DAC). Under the non-hydrostatic condition, the emergence of new Raman peaks and discontinuities in Raman shifts, FWHMs, as well as electrical conductivity well disclosed a hydrogen-disordering structural phase transition in brucite from the ordered (P3\u00afm1 symmetry)\u2013disordered (P3\u00af symmetry) structure at 5.7 GPa. Under hydrostatic condition, this transformation occurs at a lower pressure of 3.6 GPa using the 4:1 methanol\u2013ethanol mixture (ME) as the pressure-transmitting medium (PTM), which can be attributed to the influence of deviatoric stress within the sample chamber. The reversibility of this transformation is confirmed by the recovery of Raman peaks and electrical conductivity upon decompression. Furthermore, the high-temperature and high-pressure electrical conductivity results clearly revealed a negative Clapeyron slope for the hydrogen-disordering transformation in brucite, and the corresponding high P\u2013T phase diagram was established for the first time at pressures up to 7.0 GPa and temperatures up to 873 K, which can be expressed as P\u00a0(GPa)\u00a0=\u00a08.664\u00a0(\u00b11.511)\u00a0\u2212\u00a00.008\u00a0(\u00b10.002)\u00a0T\u00a0(K). These results provide direct experimental constraints on the high-pressure phase stability and structural phase transition of brucite and offer an important reference for understanding the behavior of other hydroxide minerals under extreme conditions.<\/jats:p>","DOI":"10.3390\/molecules31101631","type":"journal-article","created":{"date-parts":[[2026,5,12]],"date-time":"2026-05-12T16:04:36Z","timestamp":1778601876000},"page":"1631","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Hydrogen-Disordering Transformation and High-Temperature and High-Pressure Phase Diagram of Brucite: Insights from Raman Spectroscopy and Electrical Conductivity"],"prefix":"10.3390","volume":"31","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-7833-5168","authenticated-orcid":false,"given":"Mingyu","family":"Wu","sequence":"first","affiliation":[{"name":"Key Laboratory of High-Temperature and High-Pressure Study of the Earth\u2019s Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9081-765X","authenticated-orcid":false,"given":"Lidong","family":"Dai","sequence":"additional","affiliation":[{"name":"School of Physics and Electronic Science, Guizhou Normal University, Guiyang 550025, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haiying","family":"Hu","sequence":"additional","affiliation":[{"name":"School of Physics and Electronic Science, Guizhou Normal University, Guiyang 550025, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1261-5371","authenticated-orcid":false,"given":"Chuang","family":"Li","sequence":"additional","affiliation":[{"name":"Key Laboratory of High-Temperature and High-Pressure Study of the Earth\u2019s Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100049, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"127","DOI":"10.2138\/am.2006.1886","article-title":"High-pressure proton disorder in brucite","volume":"91","author":"Mookherjee","year":"2006","journal-title":"Am. Miner."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"8267","DOI":"10.1029\/2019JB017934","article-title":"High-temperature vibrational spectra between Mg(OH)2 and Mg(OD)2: Anharmonic contribution to thermodynamics and D\/H fractionation for brucite","volume":"124","author":"Zhu","year":"2019","journal-title":"J. Geophys. Res. Solid Earth"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"038101","DOI":"10.1088\/0256-307X\/38\/3\/038101","article-title":"Phase stability and hydroxyl vibration of brucite Mg(OH)2 at high pressure and high temperature","volume":"38","author":"Gui","year":"2021","journal-title":"Chin. Phys. Lett."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"egac100","DOI":"10.1093\/petrology\/egac100","article-title":"Formation and preservation of brucite and awaruite in serpentinized and tectonized mantle in central British Columbia: Implications for carbon mineralization and nickel mining","volume":"63","author":"Steinthorsdottir","year":"2022","journal-title":"J. Petrol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2517","DOI":"10.1029\/1999GL900558","article-title":"Hydrous minerals in the mantle wedge and the maximum depth of subduction thrust earthquakes","volume":"26","author":"Peacock","year":"1999","journal-title":"Geophys. Res. Lett."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1007\/s00269-016-0857-y","article-title":"A dihydroxylation kinetics study of brucite Mg(OH)2 at elevated pressure and temperature","volume":"44","author":"Liu","year":"2016","journal-title":"Phys. Chem. Miner."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1007\/BF00202300","article-title":"Static compression and H disorder in brucite, Mg(OH)2, to 11 GPa: A powder neutron diffraction study","volume":"22","author":"Catti","year":"1995","journal-title":"Phys. Chem. Miner."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"222","DOI":"10.2138\/am-1995-3-403","article-title":"High-pressure phase transition in brucite, Mg(OH)2","volume":"80","author":"Duffy","year":"1995","journal-title":"Am. Miner."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"396","DOI":"10.1007\/s00269-002-0243-9","article-title":"High-pressure phase transition and behavior of protons in brucite Mg(OH)2: A high-pressure-temperature study using IR synchrotron radiation","volume":"29","author":"Shinoda","year":"2002","journal-title":"Phys. Chem. Miner."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"33","DOI":"10.2138\/am.2013.4117","article-title":"Compression and structure of brucite to 31 GPa from synchrotron X-ray diffraction and infrared spectroscopy studies","volume":"98","author":"Ma","year":"2013","journal-title":"Am. Miner."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"110078","DOI":"10.1016\/j.jpcs.2021.110078","article-title":"Brucite [Mg(OH)2] under small perturbation: A combined first principles and synchrotron X-ray diffraction study","volume":"154","author":"Pillai","year":"2021","journal-title":"J. Phys. Chem. Solids"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1046","DOI":"10.2138\/am-2024-9474","article-title":"Equilibrium oxygen isotope fractionation in Mg(OH)2-Ca(OH)2-H2O: Insights from in situ high-temperature and high-pressure vibrational spectroscopy","volume":"110","author":"Zhu","year":"2025","journal-title":"Am. Miner."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2751","DOI":"10.1002\/2016JB013767","article-title":"Influence of dehydration on the electrical conductivity of epidote and implications for high-conductivity anomalies in subduction zones","volume":"122","author":"Hu","year":"2017","journal-title":"J. Geophys. Res. Solid Earth"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Hong, M.L., Dai, L.D., Hu, H.Y., Zhang, X.Y., and Li, C. (2022). High-temperature and high-pressure phase transition of natural barite investigated by Raman spectroscopy and electrical conductivity. Front. Earth Sci., 10.","DOI":"10.3389\/feart.2022.864183"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"101918","DOI":"10.1016\/j.gsf.2024.101918","article-title":"Constraints on the spin-state transition of siderite from laboratory-based Raman spectroscopy and electrical conductivity under high temperature and high pressure","volume":"16","author":"Zhang","year":"2025","journal-title":"Geosci. Front."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"531","DOI":"10.1080\/00387010.2018.1522646","article-title":"High-pressure electrical conductivity and Raman spectroscopy of chalcanthite","volume":"51","author":"Pu","year":"2018","journal-title":"Spectrosc. Lett."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Yang, L.F., Dai, L.D., Li, H.P., Hu, H.Y., Hong, M.L., and Zhang, X.Y. (2020). The phase transition and dehydration in epsomite under high temperature and high pressure. Crystals, 10.","DOI":"10.3390\/cryst10020075"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"385","DOI":"10.2138\/am-2021-7863","article-title":"Pressure-induced structural phase transitions in natural kaolinite investigated by Raman spectroscopy and electrical conductivity","volume":"107","author":"Hong","year":"2022","journal-title":"Am. Miner."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"645","DOI":"10.1186\/BF03352725","article-title":"Electrical conductivity measurements of brucite under crustal pressure and temperature conditions","volume":"59","author":"Katsura","year":"2007","journal-title":"Earth Planets Space"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"813","DOI":"10.1002\/2013GL058627","article-title":"Pressure-induced enhancement of proton conduction in brucite","volume":"41","author":"Guo","year":"2014","journal-title":"Geophys. Res. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"101342","DOI":"10.1016\/j.gsf.2021.101342","article-title":"Partial dehydration of brucite and its implications for water distribution in the subducting oceanic slab","volume":"13","author":"Guo","year":"2022","journal-title":"Geosci. Front."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2450","DOI":"10.2138\/am-2017-6146","article-title":"Electrical conductivity of mudstone before and after dehydration at high temperatures and pressures","volume":"102","author":"Sun","year":"2017","journal-title":"Am. Miner."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1016\/j.epsl.2018.06.003","article-title":"Effect of dehydrogenation on the electrical conductivity of Fe-bearing amphibole: Implications for high conductivity anomalies in subduction zones and continental crust","volume":"498","author":"Hu","year":"2018","journal-title":"Earth Planet. Sci. Lett."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"e2024JB029140","DOI":"10.1029\/2024JB029140","article-title":"The role of \u03b1\u2212\u03b2 quartz transition in fluid storage in crust from the evidence of electrical conductivity","volume":"129","author":"Hu","year":"2024","journal-title":"J. Geophys. Res. Solid Earth"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Dai, L.D., Hu, H.Y., Jiang, J.J., Sun, W.Q., Li, H.P., Wang, M.Q., Vallianatos, F., and Saltas, V. (2020). An overview of the experimental studies on the electrical conductivity of major minerals in the upper mantle and transition zone. Materials, 13.","DOI":"10.3390\/ma13020408"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1031","DOI":"10.1016\/j.gsf.2020.05.017","article-title":"High-pressure investigations on the isostructural phase transition and metallization in realgar with diamond anvil cells","volume":"12","author":"Yang","year":"2021","journal-title":"Geosci. Front."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Zhang, X.Y., Dai, L.D., Hu, H.Y., and Li, C. (2023). Pressure-induced reverse structural transition of calcite at temperatures up to 873 K and pressures up to 19.7 GPa. Minerals, 13.","DOI":"10.3390\/min13020188"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"427","DOI":"10.4028\/www.scientific.net\/AMR.412.427","article-title":"Optical properties of Mg(OH)2 using first-principles method","volume":"412","author":"Ren","year":"2012","journal-title":"Adv. Mater. Res."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1016\/j.apt.2016.08.014","article-title":"Atomic scale study of the dehydration\/structural transformation in micro and nanostructured brucite [Mg(OH)2] particles: Influence of the hydrothermal synthesis conditions","volume":"28","author":"Milosevic","year":"2017","journal-title":"Adv. Powder Technol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"506101","DOI":"10.1088\/0953-8984\/19\/50\/506101","article-title":"Structural studies of disordered materials using high-energy X-ray diffraction from ambient to extreme conditions","volume":"19","author":"Kohara","year":"2007","journal-title":"J. Phys. Condens. Matter."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"225","DOI":"10.1146\/annurev-biophys-042910-155349","article-title":"SAXS studies of ion\u2013nucleic acid interactions","volume":"40","author":"Pollack","year":"2011","journal-title":"Annu. Rev. Biophys."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1800064","DOI":"10.1002\/smtd.201800064","article-title":"Synchrotron X-ray and neutron diffraction, total scattering, and small-angle scattering techniques for rechargeable battery research","volume":"2","author":"Ren","year":"2018","journal-title":"Small Methods"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"372","DOI":"10.1002\/cjce.23747","article-title":"Experimental methods in chemical engineering: X-ray diffraction spectroscopy-XRD","volume":"98","author":"Khan","year":"2020","journal-title":"Can. J. Chem. Eng."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1554","DOI":"10.2138\/am-2015-5110","article-title":"Dependence of R fluorescence lines of rubies on Cr3+ concentration at various temperatures, with implications for pressure calibrations in experimental apparatus","volume":"100","author":"Gao","year":"2015","journal-title":"Am. Miner."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"066103","DOI":"10.1063\/1.5093949","article-title":"Characterization of metallization and amorphization for GaP under different hydrostatic environments in diamond anvil cell up to 40.0 GPa","volume":"90","author":"Dai","year":"2019","journal-title":"Rev. Sci. Instrum."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1687","DOI":"10.2138\/am.2009.3188","article-title":"Anharmonic OH vibrations in brucite: Small pressure-induced redshift in the range","volume":"94","author":"Mitev","year":"2009","journal-title":"Am. Miner."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"211","DOI":"10.1063\/1.48729","article-title":"Structure and bonding in hydrous minerals at high pressure: Raman spectroscopy of alkaline earth hydroxides","volume":"341","author":"Duffy","year":"1995","journal-title":"AIP Conf. Proc."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"L05312","DOI":"10.1029\/2007GL033062","article-title":"A crystalline-to-crystalline phase transition in Ca(OH)2 at 8 GPa and room temperature","volume":"35","author":"Catalli","year":"2008","journal-title":"Geophys. Res. Lett."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2394","DOI":"10.1002\/2016GC006282","article-title":"Influence of temperature, pressure, and oxygen fugacity on the electrical conductivity of dry eclogite, and geophysical implications","volume":"17","author":"Dai","year":"2016","journal-title":"Geochem. Geophys. Geosyst."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"475501","DOI":"10.1088\/0953-8984\/28\/47\/475501","article-title":"Evidence of the pressure-induced conductivity switching of yttrium-doped SrTiO3","volume":"28","author":"Dai","year":"2016","journal-title":"J. Phys. Condens. Matter."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"e2020JB020309","DOI":"10.1029\/2020JB020309","article-title":"Electrical conductivity of Ti-bearing hydrous olivine aggregates at high temperature and high pressure","volume":"125","author":"Dai","year":"2020","journal-title":"J. Geophys. Res. Solid Earth"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"543","DOI":"10.1007\/s00269-011-0426-3","article-title":"Electrical conductivity of polycrystalline Mg(OH)2 at 2 GPa: Effect of grain boundary hydration\u2013dehydration","volume":"38","author":"Gasc","year":"2011","journal-title":"Phys. Chem. Miner."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"396","DOI":"10.1093\/gji\/ggt511","article-title":"Mantle transition zone structure beneath India and western China from migration of PP and SS precursors","volume":"197","author":"Lessing","year":"2014","journal-title":"Geophys. J. Int."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"28645","DOI":"10.1073\/pnas.2017312117","article-title":"Greigite (Fe3S4) is thermodynamically stable: Implications for its terrestrial and planetary occurrence","volume":"117","author":"Subramani","year":"2020","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Su, C., Liu, Y.G., Fan, D.W., Song, W., Jiang, J.Y., Sun, Z.J., and Yang, G. (2022). Thermodynamic properties of Fe-bearing wadsleyite and determination of the olivine-wadsleyite phase transition boundary in (Mg,Fe)2SiO4 system. Front. Earth Sci., 10.","DOI":"10.3389\/feart.2022.879678"}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/31\/10\/1631\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,12]],"date-time":"2026-05-12T16:04:53Z","timestamp":1778601893000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/31\/10\/1631"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,12]]},"references-count":45,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2026,5]]}},"alternative-id":["molecules31101631"],"URL":"https:\/\/doi.org\/10.3390\/molecules31101631","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,12]]}}}