Помогите с химией, пожалуйста! Что означает запись?

CaH2, NaH, AlH3, SiH4, CH4, PbH4, CuH, NH3, HCl, MgH2, SnH4, HBr, BH3, PH3,
CrH3, FeH2, AsH3, BaH2, H2S, HF
CaF2, NF3, ClF7, NaCl, BaF2, SnF4, AsF5, MnF6, KF, PbF2
CaO, Al2O3, BaO, SO2, CO, As2O3, N2O5, K2O, SnO2, Br2O7, SO3, N2O3, P2O5,
Na2S, K3P, AgCl, MgBr2, Na3N, Al4C3, Fe2As3, FeCl3, SnI4, Na3B, Cr4Si3, Mg3N2, BaS, Na2Se, AuCl3, Zn3P2, Al2S3, PbC
CS2, SiCl4, SBr6, AsN, NCl5, PBr5, ICl3, CBr4, NP, As2S3, NCl5
HNO3, H2SO4, H2SO3, H3PO4, H2Cr2O7, HMnO4, HNO2, H2CrO4, H3BO3, H2CO3, H5IO6, H2S2O3, H2MnO4, HClO3, HBrO4, H2S2O7