Pure Metals

PURE METALS
*TANTALUM:
MP: 2996*C
BP:5429*C
D:16.69
very resistant to chemical attack
reacts with fluorine,chlorine,oxygen[on heating],at high temperatures,absorbs several times its
volume of hydrogen;combines with nitrogen and carbon

*SILICON:
silicon dioxide is quartz
poor conductor of electricity
D 25/4 2.33
M.P.:1410*c
attacked by hydrogen fluoride or HNO4 +HF;soluble in molten alkali metals;burns in Fl/Cl

*BORAZON:
boron nitride
hardest substance known
M.P.:3000*c[amorphous modification]
resistant to chemical attack