Irin je àdàlú ni pataki julo idẹ pelu akoonu adú larin 0.2 and 1.7 or 2.04% ni iwuwosi. Adu ni o dinwoju lati se adalu mo idẹ sugbon a tun le lo adalu awon apilese miran manganisi, kromiomu, banadiomu ati wolframu. Adu ati awon apilese miran n sise bi imule sinsin lati dena ifo ninu atomu ayonu. Ashby, Michael F.; & David R. H. Jones (1992) [1986] (in English). Engineering Materials 2 (with corrections ed.). Oxford: Pergamon Press. ISBN 0-08-032532-7.