<P> where k = thermal conductivity, ρ = density, and c = specific heat capacity of the material of interest, T 0 (\ displaystyle T_ (0)) is the initial temperature of the material (or the temperature of the bulk material). </P> <P> Temperatures vary widely in the literature and should only be used as estimates . Factors that may cause variation include partial pressure of oxygen, altitude, humidity, and amount of time required for ignition . Generally the autoignition temperature for hydrocarbon / air mixtures decreases with increasing molecular mass and increasing chain length . The autoignition temperature is also higher for branched - chain hydrocarbons than for straight - chain hydrocarbons . </P> <Table> <Tr> <Th> Substance </Th> <Th> Autoignition </Th> <Th> Note </Th> </Tr> <Tr> <Td> Triethylborane </Td> <Td> 7002253149999999999 ♠ − 20 ° C (− 4 ° F) </Td> <Td> </Td> </Tr> <Tr> <Td> Silane </Td> <Td> 7002294150000000000 ♠ 21 ° C (70 ° F) </Td> <Td> or below </Td> </Tr> <Tr> <Td> White phosphorus </Td> <Td> 7002307150000000000 ♠ 34 ° C (93 ° F) </Td> <Td> on contact with an organic substance, melts otherwise </Td> </Tr> <Tr> <Td> Carbon disulfide </Td> <Td> 7002363150000000000 ♠ 90 ° C (194 ° F) </Td> <Td> </Td> </Tr> <Tr> <Td> Diethyl ether </Td> <Td> 7002433150000000000 ♠ 160 ° C (320 ° F) </Td> <Td> </Td> </Tr> <Tr> <Td> Gasoline (Petrol) </Td> <Td> 7002520150000000000 ♠ 247--280 ° C (477--536 ° F) </Td> <Td> </Td> </Tr> <Tr> <Td> Ethanol </Td> <Td> 7002638150000000000 ♠ 365 ° C (689 ° F) </Td> <Td> </Td> </Tr> <Tr> <Td> Diesel or Jet A-1 </Td> <Td> 7002483150000000000 ♠ 210 ° C (410 ° F) </Td> <Td> or below </Td> </Tr> <Tr> <Td> Butane </Td> <Td> 7002678150000000000 ♠ 405 ° C (761 ° F) </Td> <Td> </Td> </Tr> <Tr> <Td> Paper </Td> <Td> 7002491150000000000 ♠ 218--246 ° C (424--475 ° F) </Td> <Td> </Td> </Tr> <Tr> <Td> Leather / parchment </Td> <Td> 7002473150000000000 ♠ 200--212 ° C (392--414 ° F) </Td> <Td> </Td> </Tr> <Tr> <Td> Magnesium </Td> <Td> 7002746150000000000 ♠ 473 ° C (883 ° F) </Td> <Td> </Td> </Tr> <Tr> <Td> Hydrogen </Td> <Td> 7002809150000000000 ♠ 536 ° C (997 ° F) </Td> <Td> </Td> </Tr> </Table> <Tr> <Th> Substance </Th> <Th> Autoignition </Th> <Th> Note </Th> </Tr>

What is the temperature at which paper burns