KALTSIY

KALTSIY (Calcium, az lot. calx – ohak), Sa, elementi khimiyavii guruhi II sistemai davrai Mendeleev, mansubi metallhoi ishqorzamin; raqami at. 20, massai at. 40, 08. Avvalin bor s. 1808 G. Devi judo kardaast. K.-i tabii az omekhtai 6 izotopi sobit (40Ca, 42Ca, 43Ca, 44Ca 46Ca va 48Ca) iborat ast, ki az onho 40Ca (96, 97%) beshtar pahn shudaast.
K. metalli sabuk, safedi nuqratob; t gud. 851°S, t jush. 1482°S, zichiash 1540 kg/m3 (20°S). K.-i kholis metalli narm ast. Dar payvasthoyash duvalenta; az jihati khimiyavi nihoyat faol. K. dar haror. muqarrari bo oksigen va namii havo oksid shuda, ba Ca(OH)2 tabdil meyobad; hangomi garm kardan, dar havo yo oksigen – oksid, bo gidrogen – gidrid, bo nitrogen – nitrid, bo karbon – karbid hosil mekunad. Ba ob va kislotaho tasir karda, gidrogenro judo mekunad. Bo metallho (Al, Ag, Au, Mg, Pb, Sn va g.) metallidho hosil menamoyad. Mavjudiyati K. dar qishri Zamin 2,96% ast.
K. dar organizm yake az elementhoi biogenii zaruri ba shumor meravad. Vay dar tarkibi hama boftaho mavjud ast. Dar baze organizmho to 38% (dar odam 1,4 – 2%)-ro tashkil mekunad. Qismi ziyodi K. (to 97 – 99%) dar organizm baroi tashakkuli skelet sarf meshavad. Miqdori Ca dar khuni odam bo gormonhoi gadudhoi siparshakl va nazdsiparshakl ba tanzim ovarda meshavad. Darajai hazmshavii K. ba tanosubi Ca, P va charb dar khurok vobasta buda, hangomi kohishi miqdori turshii ruda sust meshavad. Ikhtiloli mubodilai fosforu K. dar organizmi kudak sababi rakhit, dar organizmi odami bolig sababi tagyiroti tarkib va sokhti skelet megardad.
Dar tib doruhoi K.-dor hangomi norasoii ionhoi Ca2+ dar organizm (spazmofiliya, rakhit va g.), muolijai bemorihoi allergi, protsesshoi iltihobi (pnevmoniya, plevrit va g.), baze bemorihoi pust va g. istifoda meshavad. Gach (CaSO4) dar jarrohi baroi gachbandi va bur (CaCO3) hangomi baland shudani turshii shirai meda va tayyor kardani khokai dandonshui ba kor meravand.
Ba sifati doruhoi K. glyukonati kaltsiy, laktati kaltsiy va khloridi kaltsiyro kor mefarmoyand.