# What is the lowest temperature tungsten starts sublimating at?

What is the lowest temperature tungsten starts sublimating at? I've tried to search in Google but without any luck.

For example, $$\ce{WO3}$$ starts sublimating roughly at $$\pu{550 °C}$$, according to the paper Growth of epitaxial tungsten oxide nanorods.

• There is no such thing. Any compound has some vapor pressure at any temperature. Of course, for tungsten at room temperature it would be negligibly low. If you want to know when the pressure hits some particular threshold, define the threshold first. – Ivan Neretin May 5 '16 at 5:50
• Let's say 0.001 Pa. – Capo Pavel Mestre May 5 '16 at 7:14
• Now that's a sensible question. Wait a sec, I'll check my figures. – Ivan Neretin May 5 '16 at 8:01
• Maybe it would be better to share your figures, since I might want to know the temperature at a different pressure... :) – Capo Pavel Mestre May 5 '16 at 8:09

Well, you see, searching online for "vapor pressure at such-and-such temperature" (or conversely, "temperature to get such-and-such pressure") is often fruitless, and unnecessary too, because pretty decent approximations are known. Here is one: $$\ln\mathfrak p=-{\Delta H\over R}\left({1\over T}-{1\over T_0}\right)$$ where $\mathfrak p$ is your vapor pressure in atmospheres, $\Delta H$ is the enthalpy of vaporization and $T_0$ is the boiling temperature at normal pressure. For tungsten, the latter two are reported as 774 kJ/mol and 6203 K, respectively. Now you may plug in your desired pressure and solve for temperature.
• Kurt J. Lesker has a gigantic table of materials and the temperatures at which they achieve a vapour pressure of $10^{-8}$, $10^{-6}$ and $10^{-4}\ \mathrm{torr}$. For tungsten, these are $2117$, $2407$ and $2757\ \mathrm{ºC}$, respectively. For $\ce{WO3}$, only the highest vapour pressure has a tabulated temperature, at $980\ \mathrm{ºC}$ – Nicolau Saker Neto May 5 '16 at 10:06
• I've never seen pressure denoted with a Fraktur character $\mathfrak p$ in non-German texts. Does it mean anything specific? – andselisk Jan 30 '19 at 8:48