Chromium oxide

Ob peb tshuaj tebchaw muaj ob yooj yim hais - Kr thiab O, - mus rau ib tug hauv chav kawm ntawv ntawm inorganic tebchaw - oxides. Lawv cov npe - chromium oxide, noj ntxiv sau rau hauv Roman numerals qhia valence ntawm cov hlau. Lwm yam npe thiab lawv tshuaj qauv:

• chromium (II) oxide - chromium oxide, CrO;
• chromium (III) oxide - chromic ntsuab, chromium sesquioxide, Cr2O3;
• chromium (IV) oxide - chromium oxide, CrO2;
• chromium (VI) oxide - chromic anhydride, chromium trioxide, CrO3.

A compound nyob rau hauv uas lub hlau shestivalenten thiab muaj siab oxide ntawm chromium. Qhov no cov khoom, ntxhiab, nyob rau hauv tsos raws li ib tug maub liab muaju (nyob rau hauv cov huab cua, lawv kis tau tawm vim yog lub muaj zog hygroscopic). Hniav puas hnyav - 99.99 g / tus nas. Ceev nyob rau hauv 20 ° C sib npaug zos rau 2,70 g / cm³. Melting point - 197 ° C, tus kub - 251 ° C. Thaum 0 ° C nyob rau hauv cov dej yaj 61,7 g / 100 ntawm 25 ° C - 63 g / 100 ml ntawm 100 ° C - 67,45 g / 100 ml. Lub oxide yog tseem yaj nyob rau hauv sulfuric acid (chromic no sib tov, uas yog siv nyob rau hauv txoj kev kuaj rau tshuaj lom neeg ntxuav tais diav) thiab nitric acid, ethanol, ethyl ether, acetic acid, acetone. Thaum 450 ° C decomposes rau Cr2O3.

Chromium (VI) oxide yog siv nyob rau hauv tus txheej txheem ntawm electrolysis (rau cov ntshiab chromium) rau chromating zinc khoom, electrolytic plating, raws li ib tug muaj zog oxidizing neeg sawv cev (rau zus tau tej cov indigo, isatin). Dua chromium oxide yog siv rau tebchaws cawv nyob rau hauv exhaled cua. Cov tshuaj tiv thaiv tau nyaij raws li lub tswvyim: 4CrO3 + 6H2SO4 + 3C2H5OH → 2Cr2 (SO4) 3 + 3CH3COOH + 9H2O. Lub xub ntiag ntawm dej cawv qhia ib tug tov hloov xim (puv ntsuab).

Chromium (VI) oxide, raws li zoo raws li tag nrho cov hexavalent Cr, yog ib tug muaj zog tshuaj lom (tuag koob tshuaj - 0.1 g). Vim hais tias ntawm nws cov high kev ua si CrO3 ua ignition (nrog explosions) organic tshuaj , nyob rau hauv kev sib cuag nrog lawv. Dua li ntawm qhov uas tsis muaj volatility, ntau dua qhov lub chromium oxide yog txaus ntshai yog tias nqus tau cov pa, raws li yog mob ntsws cancer. Thaum kev sib cuag nrog cov tawv nqaij (txawm yog hais tias nws yog muab tshem tawm sai) ua rau voos, dermatitis, eczema, provokes tus txoj kev loj hlob ntawm cancer.

Tetravalent chromium oxide nrog CrO2 zoo li yog ib tug khoom nyob rau hauv daim ntawv ntawm cov dub tetrahedral ferromagnetic muaju. Chromium oxide muaj ib tug hniav puas loj ntawm 4 83.9949 g / mol, ceev 4,89 g / cm³. Cov tshuaj yeeb dej caw melts ib txhij decomposing, nyob ib tug kub ntawm 375 ° C. Cov dej tsis yaj. Nws yuav siv nyob rau hauv magnetic cov ntaubntawv povthawj siv xov xwm raws li cov ua hauj lwm substance. Nrog rau cov muaj koob meej ntawm CD-ROM thiab DVD-ROM tsav siv chromium (IV) oxide poob. Nws twb xub tsim nyob rau hauv 1956 los ntawm ib tug chemist los ntawm EI DuPont lub tuam txhab Norman L. Cox ntawm decomposition ntawm chromium trioxide nyob rau hauv lub xub ntiag ntawm dej nyob ib tug kub ntawm 640 ° C thiab ib tug siab ntawm 200 MPa. Raws li DuPont daim ntawv tso cai muab los ntawm Sony nyob rau Nyiajpoom Teb thiab BASF nyob rau hauv lub teb chaws Yelemees.

3 chromium oxide Cr2O3 yog ib tug zoo-grained khoom cov ntaub ntawv uas los ntawm lub teeb rau tsaus ntsuab. Hniav puas loj sib npaug 151,99 g / mol. Ceev - 5,22 g / cm³. Melting point - 2435 ° C, boiling - 4000 ° C. Lub refractive index ntawm qhov kev ntshiab tshuaj - 2.551. Qhov no oxide yog tsis soluble nyob rau hauv dej, haus dej cawv, acetone, acid. Raws li nws txoj kev cov kev ceev ntawm Corundum ceev, nws yog muab nyob rau hauv formulations polishing agents (e.g., muab tshuaj txhuam GOI). Qhov no yog ib tug ntawm cov yooj yim oxides ntawm chromium, uas yog siv raws li ib tug xim. Rau cov thawj lub sij hawm nyob rau hauv pub leejtwg technology uas nws tau txais nyob rau hauv 1838 nyob rau hauv daim ntawv ntawm ib tug pob tshab hydrated daim ntawv. Nyob rau hauv cov xwm, nyob rau hauv daim ntawv ntawm cov chrome hlau ore FeO • Cr2O3.

Divalent chromium oxide - khoom dub los yog liab xim nrog ib tug melting point ntawm 1550 ° C. Melts nrog decomposition. Hniav puas hnyav - 67,996 g / mol. Chromium oxide (II) ntawm liab xim yog tsis pyrophoric, thiab tib lub substance yog ib tug dub pyrophoric. Hmoov ignites nthawv nyob rau hauv huab cua, ces nws yuav muab cia rau tsuas nyob rau hauv ib tug txheej ntawm dej, raws li nws tsis nrog nws. Dub oxide ntawm chromium yog heev yooj yim mus nrhiav tau nyob hauv cov ntshiab daim ntawv.

Rau chromium oxide nrog qis valence raug yooj yim zog, thiab rau lub oxide nrog lub siab valence - acid.