The present invention relates to an inorganic reaction system used in the manufacture of electroconductive pastes. The inorganic reaction system comprises a lead containing matrix forming composition and a tellurium oxide additive. Preferably the lead containing matrix forming composition is between 5-95 wt. % of the inorganic reaction system, and the tellurium oxide additive is between 5-95 wt. % of the inorganic reaction system. The lead containing matrix forming composition may be a glass frit, and may comprise lead oxide. Another aspect of the present invention relates to an electroconductive paste composition that comprises metallic particles, an inorganic reaction system as previously disclosed, and an organic vehicle. Another aspect of the present invention relates to an organic vehicle that comprises one or more of a binder, a surfactant, a solvent, and a thixatropic agent. Another aspect of the present invention relates to a solar cell printed with an electroconductive paste composition as disclosed, as well as an assembled solar cell module. Another aspect of the present invention relates to a method of producing a solar cell.