Payvasthoi mudokhil, payvasthoi khimiyavie, ki dar natijai ba kovokii panjarai kristalli yo molekulai yagon modda daromadani molekulai moddai digar hosil meshavand; molekulahoi qabulshavavda boyad konfigurasiyae doshta boshand, ki ba shakli „kovoki muvofik, oyad. Molekulahoi dokhilgashtaro dar Payvasthoi mudokhil quvvahoi bayni molekulavi nigoh medorand. Payvasthoi mudokhil moddahoi noustuvor buda, dar mahlulho ba moddahoe, ki az onho tarkib yoftaand, chudo meshavand.
Payvasthoi mudokhilro baroi az ham judo kardani omekhtaho ba kor mebarand. Masalan, karbamid baroi chudo kardani karbogadridhoi khatti va tiokarbamid baroi judo kardani karbogidridhoi shokha-shokha istifoda meshavad. Alyumosilikatnoy kalsiyu natriy (seolitho)-ro boshad, baroi khushkonidani gazho, az ham judo kardani moddahoi gunogun, dar prosesshoi muovizai ioni ba kor mebarand. Payvasthoi mudokhil dar khromatografiyai adsorbsioni va digar sohahoi tahlili niz ba kor meravad.