“…The growth of single crystals is usually accompanied by purifying liquid metals to high purity. It is demonstrated by preparation of the high-purity refractory metals with the residual impurities at the level of detection of the modern analytical techniques (Alonzo et al, 1995;Bdikin et al, 1999;Bozhko et al, 2008;Chaika et al, 2009;Brunner & Glebovsky, 2000a, 2000bCortenraad et al 2001aCortenraad et al , 2001bCortenraad et al , 2001cCortenraad et al , 2001dErmolov et al, , 2002Glebovsky et al, 1998;Markin et al, 2006Markin et al, , 2010Moest et al, 1998;Shipilevsky & Glebovsky, 1989). The most problematic metals in growing the single crystals of the refractory metals (molybdenum, tungsten, niobium, and tantalum) are two -molybdenum and tungsten.…”