2K3PO4+5C+3SiO2=2P+3K2SiO3+5CO
P(+5) +5e=P(0) -2-в-ние;ок-ль
C(0) -2e= C(+2) -5-ок-ние; в-ль
2P(+5) +5C =2P +5C(+2)
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