The mercury concentration in coal varies in a wide range from less then 1 ppb to 300 ppm(more than 5 orders of magnitude).Generally,the mercury content in coal is determined by geological position of the coal deposit and syngenetic or subsequent geochemical processes rather than by the coal type(hard,brown,gas,jet,or fat).Geological transformation,such as fossilization,metamorphism and subsequent geochemical migration of mercury generate different mercury species in coal and bearing strata.Mercury speciation in coal can be represented by syngenetic mercury,initially bound to organic matrix,by elemental Hg,isomorphic in sulfides,bound to silica minerals.These species show different properties and behavior both in geochemical cycling and in technological processing.Mercury species having different matrix binding energy can be determined by so-called thermospeciation analyses based on detection of mercury release from a sample during its gradual heating(thermo-scanning).The laboratory set is based on a commercially available RA-915M Zeeman mercury analyzer coupled with a PYRO-915 attachment(Lumex),which enables various sample heating modes from ambient temperature to 800 OC and real-time detection of mercury releasing from the samples(mercury thermospectra).We studied thermospectra of CRMs,artificial mixtures of minerals,contaminated soils,and coals.Thermoscanning of various types of coals from deposits in Russia,Ukraine,and South Africa reveals variously shaped termospectra of different coals having the same total concentration of mercury: from some coals main portion of mercury is released within a relatively low temperature interval below 300 OC(mercury bound by physical sorption,occluded mercury); from other coal mercury is released at much higher temperature above 400 OC(mercury bound to organic matrix and sulfides).The thermoscanning technique gives additional information about mercury speciation in coal.This can be used for better understanding of regularities of mercury geochemistry in fossil fuels,reasons of mercury enrichment in coals,and also for enhancement of coal pre-treatment technology before combustion to reduce mercury emission to atmosphere.