Silika

Pakuti zinthu mankhwala ndi chiwerengero atomiki 14, ndi mu nthawi tebulo gulu IV mu nthawi 3 ndi III zino, akhoza kupangidwa wa oxides awiri pakachitsulo, wopangidwa mwa zinthu ziwiri Si ndipo O:

• monoxide pakachitsulo, mmene Si ndiye divalent, izo okisda mankhwala chilinganizo akhoza ankayimiridwa ngati SiO;
• silika - ndi yayikulu pakachitsulo okusayidi imene Si ndiye tetravalent, chilinganizo ake mankhwala kwalembedwa monga SiO2.

Pakachitsulo (IV) okusayidi mu maonekedwe ndi timibulu mandala. kachulukidwe wa SiO2 liri 2.648 g / cm³. mankhwala chimasungunula mu kutentha osiyanasiyana kuchokera 1600 mpaka 1725 ° C, zithupsa pa 2230 ° C.

SiO2 pakachitsulo okusayidi ankadziwika kuti kuuma ake ndi mphamvu kuchokera kalelo, ambiri m'chilengedwe monga mchenga kapena khwatsi, komanso maselo makoma a diatoms. thunthu ali polymorphs ambiri, nthawi zambiri amapezeka mu njira ziwiri:

• Crystal - masoka mchere khwatsi ndi mitundu yake (kalikedo, thanthwe Krustalo, yasipi, sibu, mwala); Khwatsi ndi maziko a mchenga khwatsi, ndi chida zomangila ndi zipangizo za makampani silicate;
• amorphous kumachitika ngati mchere zachilengedwe opal dongosolo limene tinganene kuti ndi chilinganizo SiO2 • nH2O; mitundu earthy wa SiO2 amorphous ndi Tripoli (ufa thanthwe, diatomaceous lapansi) kapena diatomaceous lapansi; kupanga amorphous anhydrous silika - ndi silika, womwe wapangidwa kwa metasilicate ndi sodium.

Pakachitsulo okusayidi SiO2 ndi okusayidi acidic. Chinthu Kudziwa mankhwala katundu wake.

Fluorine amachitira ndi pakachitsulo woipa: SiO2 + 4F → SiF4 + O2 kupanga colorless pakachitsulo tetrafluoride mpweya ndi mpweya, pamene mipweya ina (halogens Cl2, Br2, I2) uthe layamba.

Pakachitsulo okusayidi Wachinayi anachita ndi asidi hydrofluoric kupeza asidi fluorosilicic: SiO2 + 6HF → H2SiF6 + 2H2O . Mundawu ntchito makampani michenga yopangira zida zamagetsi.

Pakachitsulo (IV) okusayidi kusungunuka mu osungunula kapena wotentha anaikira soda kupanga ndi sodium silicate: 2NaOH + SiO2 → Na2SiO3 + H2O.

Pakachitsulo woipa amachitira ndi oxides zofunika zitsulo (mwachitsanzo, oxides wa sodium, potassium kutsogolera (II), kapena osakaniza a okusayidi nthaka kuti ntchito yopanga galasi). Mwachitsanzo, zimene okusayidi soda ndi SiO2, chifukwa amene akhoza kupangidwa: ndi sodium orthosilicate 2Na2O + SiO2 → Na4SiO4, sodium silicate Na2O + SiO2 → Na2SiO3, ndi galasi Na2O + 6SiO2 + XO → Na2O: XO: 6SiO2. Zitsanzo za galasi amenewa ndi phindu malonda, ndi koloko-laimu galasi, borosilicate galasi, leaded galasi.

pakachitsulo woipa pa kutentha, ali anachitira ndi pakachitsulo, chifukwa mu monoxide gaseous: Si + SiO2 → 2SiO ↑.

Nthawi zambiri, silika SiO2 ntchito yopanga pakachitsulo elemental. The ndondomeko ya ntchito mogwirizana ndi elemental mpweya chimaposa pa kutentha mu ng'anjo ya magetsi: 2C + SiO2 → Si + 2 Akorinto. Ndi mphamvu ndithu mwakayakaya. Komabe, mankhwala ake ntchito mu michenga yopangira zida zamagetsi luso kwa zotsimikizira maselo dzuwa (mphamvu kuwala n'kukhala magetsi). Komanso koyera Si ntchito mu kampani yopanga zitsulo (kupanga kutentha zosagwira ndi asidi zosagwira pakachitsulo zitsulo). The Choncho analandira elemental pakachitsulo kofunika kupeza woyera pakachitsulo dioxide, umene uli wofunika kwa chiwerengero cha mafakitale. Natural SiO2 ntchito mu mawonekedwe a mchenga m'mafakitale amene musati amafuna chiyero chake m'mwamba.

Inhalation finely ufa crystalline SiO2 fumbi, ngakhale zedi ochepa kwambiri (kwa 0.1 mg / m³), ndi matenda silicosis kapena khansa akhoza kukhala pa nthawi. Fumbi amakhala oopsa ngati akulowa mapapo, zonse zosasangalatsa potero kuchepetsa ntchito zawo. Mu anthu, okusayidi pakachitsulo mu mawonekedwe a particles crystalline si kusungunuka mu nthawi kukomoka zogwirizana nthawi. Amenewa angalenge chiopsezo matenda kuntchito kwa anthu ntchito ndi zida sandblasting kapena katundu amene ali crystalline silika ufa. Ana, asthmatics amisinkhu yonse amene akudwala chifuwa, komanso anthu okalamba amadwala mwachangu.