> How can Zt for Co2TiAl = 25 ? > while for Co2TiSn = 26 > > > Sn is one column more to the right in the periodic table, and hence has one valence electron more than Al (but its total number of electrons is of course much larger than for Al). Stefaan Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm