[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-657119-105":59,"doc-detail-657119-en":134},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":127,"head_meta":129,"extra_data":131,"updated_unix":133},105,"en","e-ph-pourbaix-diagrams-module-introduction","E-pH (Pourbaix) Diagrams Module - Introduction","","E-pH (Pourbaix) diagrams map the thermodynamic stability of species in aqueous solutions as a function of pH and electrochemical potential. They show predominant species regions, bounded by stability limits for water, and allow interpretation in Eh-pH coordinates under different reference scales. The Eh-pH module in HSC Chemistry enables fast, flexible construction of diagrams at selected temperature and concentration. The text explains diagram meaning, reaction line types, water stability reactions, and key assumptions and limitations affecting calculation results.",{"@graph":69,"@context":126},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":30,"@type":76,"position":81},"https://docshare.wps.com/document/technology/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/e-ph-pourbaix-diagrams-module-introduction/657119/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/e-ph-pourbaix-diagrams-module-introduction/657119.png","ImageObject",300,407,{"name":92,"@type":93},"cryingin4k","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-30","2026-10-26",true,{"@type":102,"interactionType":103,"userInteractionCount":19},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118,122],{"name":109,"@type":110,"acceptedAnswer":111},"What do E-pH (Pourbaix) diagrams represent?","Question",{"text":112,"@type":113},"They represent thermodynamic stability areas of different species in an aqueous solution, expressed as a function of pH and electrochemical potential. The diagrams are shown in redox potential–pH coordinates and typically include water stability limits.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"How does the Eh-pH module (EpH module) in HSC Chemistry help users?",{"text":117,"@type":113},"It allows constructing E-pH diagrams quickly and with flexibility by letting users set the temperature and concentration. This enables drawing diagrams exactly at the chosen conditions.",{"name":119,"@type":110,"acceptedAnswer":120},"What types of lines appear in a Pourbaix (E-pH) diagram and what do they mean?",{"text":121,"@type":113},"Lines can be horizontal, diagonal, or vertical. Horizontal lines involve electrons but are independent of pH; diagonal lines involve both electrons and pH-related ions (H+ and OH-); vertical lines involve H+ or OH- but are independent of E (electrons do not participate).",{"name":123,"@type":110,"acceptedAnswer":124},"What are important limitations when interpreting results from the EpH module?",{"text":125,"@type":113},"Calculations assume stoichiometric substances and ideal (non-non-ideal) behavior are not included. The method also neglects reaction kinetics and can be affected by errors in thermochemical data or missing species in the database, which may distort results under some conditions.","https://schema.org",{"og:url":83,"og:type":128,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":130,"canonical":83},"index,follow",{"doc_id":132,"site_id":62},657119,1793080309,{"code":4,"msg":5,"data":135},{"doc_id":132,"user_id":136,"nickname":92,"user_avatar":137,"doc_module":4,"category_id":29,"category_name":30,"doc_title":65,"doc_description":67,"doc_content":138,"file_id":139,"file_url":140,"file_type":141,"file_size":142,"view_count":19,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":143,"language":144,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":145,"faqs":146,"seo_title":147,"seo_description":67,"update_tm":148,"read_time":36},137458181193,"https://ap-avatar.wpscdn.com/davatar_6f874abed73319feea01a86fa6f0fab8","HSC-EpH  \n1/16  \nPetri Kobylin, Lauri Mäenpää, Antti Roine, Kai Anttila September 6, 2023  \n17. E-pH (Pourbaix) Diagrams Module  \nE-pH diagrams show the thermodynamic stability areas of different species in an aqueous solution. Stability areas are presented as a function of pH and electrochemical potential scales. Usually the upper and lower stability limits of water are also shown in the diagrams by dotted lines. Traditionally, these diagrams have been taken from different handbooks 1 . However, in most handbooks, these diagrams are available only for a limited number of temperatures, concentrations, and element combinations.  \nThe Eh-pH module (EpH module is used hereafter) in HSC Chemistry allows the construction of diagrams in a highly flexible and fast way, because the user can draw the diagrams exactly at the selected temperature and concentration.  \nThe EpH module is based on STABCAL-Stability Calculations for Aqueous Systemsdeveloped by H. H. Haung, at Montana Tech. , USA2,3 .  \nMetso reserves the right to modify these specifications at any time without prior notice. Copyright © 2023, Metso Finland Oy  \nHSC-EpH  \n2/16  \nPetri Kobylin, Lauri Mäenpää, Antti Roine, Kai Anttila September 6, 2023  \n17.1. Introduction  \nE-pH diagrams are also known as Pourbaix Diagrams, after the author of the famous Pourbaix diagram handbook 1 . The simplest type of these diagrams is based on a chemical system consisting of one element and a water solution, for example, the MnH2O system. The system can contain several types of species, such as dissolved ions, condensed oxides, hydroxides, oxides, etc. The E-pH diagram shows the stability areas of these species in the redox potential-pH coordinates.  \nUsually the redox potential axis is based on the Standard Hydrogen Electrode (SHE) scale designated Eh, but other scales can also be used. The redox potential of the system represents its ability to change electrons. The system tends to remove electrons from the species when the potential is high (E > 0) . These conditions may exist near the anode in an electrochemical cell, but can also be generated with some oxidizing agents (Cu + H2O2 = CuO + H2O) . In reducing conditions, when the potential is low (E \u003C 0), the system is able to supply electrons to the species, for example, with a cathode electrode or with some reducing agents.  \nThe pH of the system describes its ability to supply protons (H(+a)) to the species. In acid conditions (pH \u003C 7), the concentration of protons is high and in caustic conditions (pH > 7) the concentration of protons is low.  \nUsually, a large amount of different species exist simultaneously in the aqueous mixtures in fixed E-pH conditions. Pourbaix diagrams simplify this situation a lot by showing only the predominant species whose content is highest in each stability area. The lines in the diagrams represent the E-pH conditions where the content of the adjacent species is the same in the equilibrium state. However, these species always exist in small amounts on both sides of these lines and may have an effect on practical applications.  \nThe lines in the diagrams can also be represented with chemical reaction equations. These reactions may be divided into three groups according to the reaction types:  \n1. Horizontal lines. These lines represent reactions that are involved with electrons, but are independent of pH. Neither H(+a) ions nor OH(-a) ions participate in these reactions.  \n2. Diagonal lines with either a positive or negative slope. These lines represent reactions that are involved with both electrons and H(+a) -and OH(-a) ions.  \n3. Vertical lines. These lines represent reactions that are involved either with H(+a)-or OH(-a) ions, but are independent of E. In other words, electrons do not participate in these reactions.  \nThe chemical stability area of the water is shown in the E-pH diagrams by dotted lines. The upper stability limit of water is based on the potential when oxygen generation starts on the an","cbCaidaFZvXDLZrK","https://ap.wps.com/l/cbCaidaFZvXDLZrK","pdf",378864,16,"English","# 17. E-pH (Pourbaix) Diagrams Module\n## 17.1 Introduction","[{\"question\":\"What do E-pH (Pourbaix) diagrams represent?\",\"answer\":\"They represent thermodynamic stability areas of different species in an aqueous solution, expressed as a function of pH and electrochemical potential. The diagrams are shown in redox potential–pH coordinates and typically include water stability limits.\"},{\"question\":\"How does the Eh-pH module (EpH module) in HSC Chemistry help users?\",\"answer\":\"It allows constructing E-pH diagrams quickly and with flexibility by letting users set the temperature and concentration. This enables drawing diagrams exactly at the chosen conditions.\"},{\"question\":\"What types of lines appear in a Pourbaix (E-pH) diagram and what do they mean?\",\"answer\":\"Lines can be horizontal, diagonal, or vertical. Horizontal lines involve electrons but are independent of pH; diagonal lines involve both electrons and pH-related ions (H+ and OH-); vertical lines involve H+ or OH- but are independent of E (electrons do not participate).\"},{\"question\":\"What are important limitations when interpreting results from the EpH module?\",\"answer\":\"Calculations assume stoichiometric substances and ideal (non-non-ideal) behavior are not included. The method also neglects reaction kinetics and can be affected by errors in thermochemical data or missing species in the database, which may distort results under some conditions.\"}]","E-pH (Pourbaix) Diagrams Module - Introduction | PDF",1792974449]