tungsten carboxylate compounds useful for coating interdigitated electrodes used in hydrogen sulfide gas sensors are disclosed . a method of coating electrodes with the compounds using a precise solution casting technique such as spin - coating or casting , dip - casting or spray - casting techniques is also described . electrodes which are solution coated with the compounds may be used to fabricate superior quality chemiresistor sensors for use in hydrogen sulfide gas sensing devices by heating the carboxylates above 350 ° c . to decompose certain carboxylates to wo 3 and others to sodium tungstate .