UmCalahle

**umCalahle**  yinhlwa yesithupha. Akusiyona insimbi -okwenza kutholakale izinzuba ezine ukuze kwakheke iminananzuba yevanga. Ingeyeqembu le-14 letafula lezikhathi. UmCalahle wakha amaphesenti ayi-0.025 ogobohla lomhlaba kuphela. Ama-isotopu amathathu avela ngokwemvelo, i-12C ne-13C izinzile, kuyilapho i-14C iyi-radionuclide, ebola inempilo eyingxenye yeminyaka engaba ngu-5 730. Ungenye wezinto ezimbalwa ezaziwa kusukela endulo.

Umcalahle uyinhlwa yeshumi nanhlanu kwezitholakala ngobuningi egobohleni likaNomkhubulwane, futhi uyinhlwa yesine eyinala kakhulu kumkhathilibe ngesisindo emva kweHwanzi, iHwelanga, kanye nesOhwe. Inala yomcalahle, nobungqayizivele bokuhluka kwawo bomxube ongokwemvelo bukwazi ukwenza lenhlwa ikhonze njengenhlwa eyaziwa kakhulu ekuphileni kwabantu. Uyinhlwa yesine eyinala emzimbeni womuntu  (esingu-18.5) emva kwesoHwe.

AmaChwe omcalahle  angathungelana ngezindlela ezihlukene, okungaphumela ekwakhekeni kwama-allotropes omcalahle angafani. Izithungo somcalahle eziqinile futhi ezizinzile. Ngokudliwa komhlaba, umcalahle wakha inqwaba yamavanga. Isibalo samavanga ahlukile sikhombisa ukuthi amaningi aqukethe umcalahle kunalawo angenawo. [81] Isimangalo esifanayo singenziwa iHwanzi ngoba iningi lemixube engokwemvelo iqukethe amavanga ehwanzi ahlanganiswe nomcalahle noma enye into ejwayelekile efana nesOhwe noma iNihwe.

Uhlobo olulula kakhulu lweChembe eliphilayo yi-hydrocarbon — umndeni omkhulu wamachembe aphilayo akhiwe ngamaChwe ehwanzi ahlanganiswe nochungechunge lwamaChwe omCalahle ontuhlambili. Umgogodla we-hydrocarbon ungashintshwa ngamanye amaChwe, aziwa ngokuthi ama-heteroatom. Ama-heteroatom avamile avela ezinhlanganisweni zezinto eziphilayo afaka isOhwe, iNihwe, iSibabuli, iPholoba, nama-halogen angenawo umsakazo, kanye nezinsimbi uMthanya nomGethe. AmaVanga angokwemvelo aqukethe uThungonsimbi aziwa njengama-organometallic compounds (bheka ngezansi). Ukuqoqwa okuthile kwamaChwe, okuvame ukufaka ama-heteroatom, kuphindaphindeka ngamanani amaningi ezinto eziphilayo. La maqoqo, aziwa njengamaqembu asebenzayo, anikeza amaphethini wokuphinda asebenze futhi avumela ukutadisha okuhlelekile nokuhlukaniswa kwamavanga angokwemvelo. Ubude beketanga, ukuma namaqembu asebenzayo konke kuthinta izakhiwo zama-molecule ephilayo.

Ezingxenyeni ezizinzile kakhulu zomcalahle (futhi cishe yonke imixube ezizinzile yezinto eziphilayo), umcalahle uthobela umthetho we-octet futhi i-tetravalent, okusho ukuthi iChwe loomcalahle lakha izibopho ezine ezihlangene (ezingabandakanya izibopho eziphindwe kabili nezintathu). Okuhlukile kufaka inani elincane lezinto zokuzinza ezizinzile (amabhondi amathathu, imali ekhokhiswayo), ama-radicals (ama-bond amathathu, angathathi hlangothi), ama-carbanion (amabhondi amathathu, inkokhiso engemihle) nama-carbenes (ama-bond amabili, angathathi hlangothi), yize lezi zinhlobo zinamathuba amaningi okuthi zibe khona uhlangane njengabalamuli abangazinzile, abasebenza kahle.

UmCalahle wenzeka kuyo yonke impilo yemvelo eyaziwayo futhi iyisisekelo sobuVanga obungokwemveli. Uma ihlanganiswe nehwanzi, yakha ama-hydrocarbon ahlukahlukene abalulekile embonini njengeziqandisi, izinto zokuthambisa, izincibilikisi, njenge-feedstock yamavanga yokwenziwa kwamapulasitiki nama-petrochemicals, futhi njengamandla okubasa.

## Imixube
Uma uxutshwe nesOhwe neHwanzi, umCalahle ungakha amaqembu amaningi eMixube ebalulekile yebhayoloji kufaka phakathi isiNcithi, ama-lignans, ama-chitin, ama-alcohol, amafutha, nama-ester anamakha, ama-carotenoids nama-terpenes. Uma uxutshwe neNihwe wakha ama-alkaloid, futhi ngokwengezwa kwesibabuli wakha ama-antibiotic, ama-amino acid, nemikhiqizo yenjoloba. Ngokwengeza iPholoba kulezi ezinye izakhi, wakha i-DNA ne-RNA, izakhi zokuthwala zeVanga, kanye ne-adenosine triphosphate (ATP), ingqamuzana elidlulisa amandla kunawo wonke kumangqamuzana aphilayo