Sciencemadness Discussion Board

Metals for thermites

chornedsnorkack - 28-5-2015 at 07:27

How chemically active are lanthanides and actinides compared to aluminum?

They are mostly high boiling, with a few exceptions like ytterbium. Do they give useful thermites, compared to aluminum?

blogfast25 - 28-5-2015 at 07:30

Quote: Originally posted by chornedsnorkack  
How chemically active are lanthanides and actinides compared to aluminum?

They are mostly high boiling, with a few exceptions like ytterbium. Do they give useful thermites, compared to aluminum?


The lanthanides are fairly comparable to aluminium, in terms of reducing abilities, e.g. reducing RE oxides with Al is impossible. Look up the Heats of Formation of the RE oxides.

But using REs for metallothermic reductions seems very redundant, since as Al (also Mg and Ca) do such a good job.

For Nd<sub>2</sub>O<sub>3</sub> e.g., Wolfram Alpha gives a HoF of - 1808 kJ/mol, slightly higher (more negative) than Al<sub>2</sub>O<sub>3</sub>.


[Edited on 28-5-2015 by blogfast25]

MeshPL - 1-6-2015 at 11:41

Using lanthanides to make thermite is comparable to extracting hydrogen bromide from bromoform using NaBH4. Or something.

I wonder what are notable oxides for thermite.

e.g. CuO. These folks in EU parliment don't know how explosive and dangerous this kind of thermite can be, since they had (or still have:() plans to ban KNO3, actuallu most common nitrates, chlorates, hypochlorites and >3% H2O2. Although Al powder is TOTALLY safe.:P

Pb3O4 is also nice, if I remember right. I wonder about oxides like SnO2 or HgO. Maybe WO3 or CrO3. Basically any oxidising oxide or oxide of unreactive metal.


blogfast25 - 1-6-2015 at 13:41

Pb3O4, SnO2 and HgO are only 'interesting' [COUGH!] if you want near-flash powders (with mercury? REALLY???)

If you want to produce real interesting metals then look at the oxides of Cr, V, Ti, Nd, W, Mn and others. Creating effective thermite formulations is a science, trust me.