M(Na3PO4)=23*3+31+16*4=164 w(Na)=69/164=0.42(42%) w(P)=31/164=0.19(19%) w(O)=64/164=0.39(39%)

CuS=64+32=96 w(Cu)=64/96=67% w(S)=32/96=33%

Al(NO2)3=27+14*3+16*6=165 w(Al)=27/165=16% W(N)= 14*3/165=25% w(O)=16*6/165=59%

CaF2=40+19*2=78 w(Ca)=40/78=51% w(F)=38/78=49%

Ba(NO2)2=137+28+64=229 w(Ba)=137/229=60% w(N)=28/229=12% w(O)=64/229=28%