X-ray photoelectron spectroscopic study of a pristine millerite (NiS) surface and the effect of air and water oxidation

Abstract

Other| December 01, 1998 X-ray photoelectron spectroscopic study of a pristine millerite (NiS) surface and the effect of air and water oxidation Daniel L. Legrand; Daniel L. Legrand INCO, Central Process Technology, Copper Cliff, ON, Canada Search for other works by this author on: GSW Google Scholar H. Wayne Nesbitt; H. Wayne Nesbitt University of Ontario, Canada Search for other works by this author on: GSW Google Scholar G. Michael Bancroft G. Michael Bancroft University of Western Ontario, Canada Search for other works by this author on: GSW Google Scholar Author and Article Information Daniel L. Legrand INCO, Central Process Technology, Copper Cliff, ON, Canada H. Wayne Nesbitt University of Ontario, Canada G. Michael Bancroft University of Western Ontario, Canada Publisher: Mineralogical Society of America First Online: 02 Mar 2017 Online ISSN: 1945-3027 Print ISSN: 0003-004X GeoRef, Copyright 2004, American Geological Institute. American Mineralogist (1998) 83 (11-12_Part_1): 1256–1265. https://doi.org/10.2138/am-1998-11-1214 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Daniel L. Legrand, H. Wayne Nesbitt, G. Michael Bancroft; X-ray photoelectron spectroscopic study of a pristine millerite (NiS) surface and the effect of air and water oxidation. American Mineralogist 1998;; 83 (11-12_Part_1): 1256–1265. doi: https://doi.org/10.2138/am-1998-11-1214 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyAmerican Mineralogist Search Advanced Search Abstract Millerite, NiS, fractured under high vacuum and reacted with air and water has been analyzed by X-ray photoelectron spectroscopy (XPS). The pristine millerite surface gives rise to photoelectron peaks at binding energies of 853.1 eV (Ni 2p (sub 3/2) ) and 161.7 eV (S 2p), thus resolving ambiguities concerning binding energies quoted in the literature. Air-reacted samples show the presence of NiSO 4 and Ni(OH) 2 species. There is evidence for polysulfide species (S n (super 2-) , where 2< or =n< or =8) on air-oxidized surfaces. These may occur in a sub-surface layer or may be intermixed with the Ni(OH) 2 in the oxidized layer. The NiSO 4 species at the millerite surface occur as discrete crystallites whereas the Ni(OH) 2 forms a thin veneer covering the entire millerite surface. The NiSO 4 crystallites form on the surface of millerite but not on surfaces of adjacent minerals. Surface diffusion of Ni (super 2+) and SO (super 2-) 4 across the millerite surface is thought to be responsible for the transport and subsequent growth of NiSO 4 crystallites developed on millerite surfaces. Although it is clear that Ni and SO (super 2-) 4 does not diffuse onto surfaces of adjacent minerals in sufficient quantity to form crystallites, the explanation is uncertain. XPS results for water-reacted surfaces show little difference from the vacuum fractured surfaces with the exception that minor amounts of polysulfide and hydroxy nickel species are present. Similar reaction products to those formed in air [NiSO 4 and Ni(OH) 2 ] are believed to be produced, but these are removed from the millerite surface by dissolution, leaving behind a sulfur-enriched surface (polysulfide) and hydroxyl groups chemisorbed to nickel ions at the millerite surface. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.