Chromium wani sinadarin ƙarfe ne mai canjawa (transition metal) mai alamar sinadari ta Cr da lambar atomic 24 a bisa jadawalin sinadarai (Periodic Table). Yana cikin rukuni na 6 na tsarin sinadarai, tare da tungsten da molybdenum. Yana da launin azurfa mai sheƙi, mai tsananin juriya ga lalacewar iska da tsatsa saboda yana samar da wani siririn fim na oxide (Cr₂O₃) a samansa wanda ke hana ci gaba da lalacewa. Wannan siffa ce ta sa chromium ya zama ginshiƙi a masana’antar ƙarafa nau’in stainless steel da sauran alloys masu juriya ga lalacewa.
Sunan “Chromium” ya samo asali ne daga kalmar Girkanci wato ”chroma”, wadda ke nufin “launi,” saboda yawancin sinadaran chromium suna da launuka masu ƙayatarwa kamar kore, rawaya, ja, da sauran su. Wannan bambancin launukan ya jawo hankalin masana tun daga lokacin gano shi har zuwa yau.
Chromium ƙarfe ne mai matuƙar muhimmanci ga ci gaban masana’antu, musamman saboda ƙarfinsa na ƙara juriya ga lalacewa. Isotopes ɗinsa suna da amfani a fannoni daban-daban, daga likitanci zuwa binciken sararin samaniya. Duk da haka, buƙatar kiyaye lafiyar ma’aikata da muhalli na da matuƙar muhimmanci saboda gubar Chromium(VI).
Tarihin gano chromium
An fara gano chromium ne a shekara ta 1797 ta hannun masanin kimiya ɗan ƙasar Faransa Louis-Nicolas Vauquelin lokacin da yake nazari kan wani dutse mai launin ja da ake kira crocoite (PbCrO₄), wanda aka fi sani da lead chromate. A cikin bincikensa, Vauquelin ya gano cewa wannan dutse yana ɗauke da wani sabon sinadari wanda bai zama a sananne ba a lokacin.
A shekara ta gaba, wato 1798, Vauquelin ya samu damar ware tsantsar chromium daga crocoite, wanda ya tabbatar da kasancewarsa a matsayin sabon sinadarin ƙarfe. Bayan haka, an fara amfani da haɗin chromium musamman a matsayin pigment a zanen gidaje da kayan ado, musamman saboda launinsa mai ƙarfi da juriya ga koɗewa.
Tarihin chromium ya kuma haɗa da tasirinsa a tarihin masana’antar ƙarafa. Daga ƙarshen ƙarni na 19 zuwa farkon ƙarni na 20, masana sun gano cewa ƙara sinadarin chromium a cikin ƙarfe yana ƙara masa ƙarfin jure wa tsatsa, wanda hakan ya haifar da ƙirƙirar abin da ake kira stainless steel. Wannan ƙirƙira ta canja masana’antu, gine-gine, da kayan aikin yau da kullum.
Siffofi da yanayin chromium
Chromium ƙarfe ne mai matuƙar ƙarfi da tauri. Yana da ƙimar taurin Mohs 8.5, wanda ya fi yawancin ƙarafa, amma bai kai taurin tungsten ba. Nauyin ƙwayoyin zarra na chromium shi ne 51.9961 u, kuma yana da tsari na lantarki [Ar] 3d⁵ 4s¹. Wannan tsari ya nuna cewa chromium yana da half-filled d-subshell, wanda ke ba shi inganci na musamman a tsarin lantarki.
Taƙaitattun bayanai
- Nauyi (Density): 7.19 g/cm³
- Zafin narkewa: 1907 °C (2180 K)
- Zafin tafasawa: 2671 °C (2944 K)
- Yanayin oxidation: +2, +3, +6 (na +3 shi ne mafi tsayayye)
- Launi: Launin azurfa mai sheƙi
- Magnetism: Yana da tsarin Antiferromagnetic a yanayin cikin ɗaki, ferromagnetic a yanayi ƙasa da 38 K
Chromium yana da ƙarfin samar da fim na Cr₂O₃ a samansa lokacin da ya haɗu da iska. Wannan fim yana da matuƙar kauri a matakin nanometer, amma yana da tasiri sosai wajen hana ruwa da iskar oxygen shiga cikin ƙarfen, wanda ke hana lalacewa.
Hanyoyin samuwar chromium
Chromium ba ya samuwa a matsayin tsantsar ƙarfe a yanayi, amma ana samun shi a cikin sinadarai masu ɗauke da iskar oxygen ko sulfur. Babban ma’adinin da ake haƙowa domin samar da chromium shi ne chromite (FeCr₂O₄). Sunadarai masu ɗauke da chromium sun haɗa da:
- Chromite (FeCr₂O₄): Babban tushen samuwar chromium.
- Crocoite (PbCrO₄),- Ana amfani da shi a kayan ado.
- Uvarovite: Wani nau’in garnet mai launin kore wanda ke ɗauke da chromium.
Kasashe masu yawan haƙar chromium sun haɗa da Afirka ta Kudu (mafi girma a duniya), Kazakhstan, Indiya, da Turkiyya. Sama da kashi 90% na chromium da ake samarwa a duniya ana amfani da shi ne wajen yin ferrochrome, wanda ake haɗawa da ƙarfe wajen yin stainless steel.
Rabe-raben Isotopes a cikin chromium
Chromium yana da isotopes guda huɗu tsayayyu: ⁵⁰Cr, ⁵²Cr, ⁵³Cr, da ⁵⁴Cr. Mafi yawan chromium a yanayi yana cikin nau’in ⁵²Cr wanda ya kai kusan kashi 83.789% na dukkan chromium a duniya.
- ⁵⁰Cr – Kusan kashi 4.345% na dukkan chromium; ana amfani da shi a nazarin nukiliya.
- ⁵²Cr – Mafi yawan isotope, tsayayye, ana amfani da shi wajen binciken ƙwayoyin halitta da ilimin sararin samaniya.
- ⁵³Cr – Kusan kashi 9.501% na dukkan chromium; ana amfani da shi a binciken ilmin ƙasa da nazarin abubuwan tarihi.
- ⁵⁴Cr – Kusan kashi 2.365%; ana amfani da shi wajen nazarin iskar sararin samaniya.
Baya ga waɗannan, chromium yana da isotopes masu gajerun lokacin rayuwa fiye da 20 waɗanda ake samarwa a ɗakin gwaje-gwaje. Mafi shahara daga cikinsu su ne:
- ⁵¹Cr – Rayuwar kwanaki 27.7 yake yi, ana amfani da shi a fannin likitanci wajen binciken jini (radioisotope tracing).
- ⁴⁹Cr da ⁵⁵Cr – Suna rayuwa na sa’o’i ko mintuna kaɗan, ana amfani da su a binciken nukiliya.
Chromium da sauran sinadarai
Chromium yana samar da nau’o’in sinadarai masu yawa a yanayin oxidation +2, +3, da +6.
- Chromium(III) oxide (Cr₂O₃): Launin kore ne, mai matuƙar juriya ga zafi, ana amfani da shi wajen polishing compounds.
- Chromium(VI) oxide (CrO₃): Ja ne mai haske, mai ƙarfi a matsayin oxidizing agent, amma yana da tsananin guba.
- Sodium dichromate (Na₂Cr₂O₇) – Launin ruwan lemo ne, ana amfani da shi a masana’antar fenti da tsabtace ƙarfe.
- Potassium chromate (K₂CrO₄): Launin rawaya ne, ana amfani da shi a gwaje-gwajen gano wasu ions.
- Chromium halides: Kamar CrCl₃ (kore) da CrF₃ (fari), suna da amfani a sinadarai da catalysis.
Amfanin chromium
- Stainless Steel: Ƙara chromium sama da 10.5% a ƙarfe yana samar da kayan da ba sa tsatsa.
- Plating: Chromium plating yana ba da kariya da ƙyalli ga kayayyakin aiki da kayayyakin ado.
- Pigments: Sinadaran chromium suna ba da launuka masu ƙarfi a zanen gida, kayan roba, da kayan ado.
- Masana’antar Aerospace: Ana amfani da alloys na chromium a injinan jirage da kayayyakin aikin roka saboda ƙarfinsu da juriya ga zafi.
- Kayayyakin aikin ƙira: High-speed steels da ake amfani da su a yankan ƙarfe suna ɗauke da chromium saboda taurinsa.
- Magani: Chromium(III) yana da amfani a tsarin metabolism na glucose, wato yana da muhimmanci a ƙanƙanen adadi.
Muhimmanci da ƙalubale
Muhimmancin chromium ya ta’allaka ne a juriyarsa ga lalacewa da tasirinsa wajen samar da kayayyaki masu ƙarfi da tsawon rai. Sai dai duk da haka, Chromium(VI) yana da tsananin guba kuma yana iya haifar da cutar daji (carcinogenic), don haka masana’antu suna bukatar tsauraran matakan kariya wajen amfani da shi.
Sabbin bincike
Masana suna nazarin yadda za a maye gurbin amfani da Chromium(VI) da wasu sinadarai marasa guba a a ayyukan plating da pigments. Haka kuma ana binciken amfani da chromium a cikin superalloys da kayan aikin ƙira masu tsanani a masana’antun makamashi.
Tasirinsa ga lafiya da muhalli
Chromium(III) yana da mahimmanci ga lafiyar ɗan’adam idan aka amfani da shi a matsakacin adadi, yayin da Chromium(VI) ke da tsananin guba. Ya kamata a guji shaƙar ƙura ko turirinsa, kuma a bi ka’idojin tsabtace muhalli wajen zubar da shararsa.
Manazarta
National Center for Biotechnology Information. (2023). Chromium. PubChem Element Summary.
Editors of Encyclopaedia. (2024). Chromium. Britannica.
Lide, D. R. (Ed.). (2004). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, FL: CRC Press.
Emsley, J. (2011). Nature’s Building Blocks: An A–Z Guide to the Elements (Revised ed.). Oxford: Oxford University Press.
*** Tarihin Wallafa Maƙalar ***
An wallafa maƙalar 11 August, 2025
An kuma sabunta ta 11 August, 2025
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