The given data of pyroxene analysis is given w%. SiO2=48.90, TiO2=.12, AL2O3=3.86, Fe2O3=4.65, Cr2O3=0, FeO=25.35, MnO=.51, MgO=6.87, CaO=7.96, Na20=.58, K20=.20, H2O+=.57, H2O-=.35, TOTAL 99.92. Calculate the chemical structural formula for this pyroxene for 6 oxygens.