Quick chemistry question

[Ika]

I can't find any information online, so I'll turn to ATOT and hope that someone smart is still online.

Is Tungsten Oxide (WO3) an insulator or conductor (of electricity)? I'm pretty sure it's an insulator, but some of my classmates confused me as to whether it really was or not.

Thanks in advance.

 

[theblackbox]

did you try google, cause i typed in tungsten oxide conducter w03 and got some first class hits.

 

[Epic Fail]

conductor of what? electricity, heat?

 

[Ika]

Originally posted by: theblackbox
did you try google, cause i typed in tungsten oxide conducter w03 and got some first class hits.

The problem with googling a non-common compound is that you usually end up with a bunch of scientific journal entries and specific applications. I just need conductor/insulator or resistivity values for the basic yellow powder form, not nanotubes or "nanocrystalline powders", whatever that is. So yes, I googled.

Originally posted by: Epic Fail
conductor of what? electricity, heat?

Electricity, sorry.

 

[Tiamat]

JACS article on Tungsten (III) Oxide thin films

Resistivity of the film was roughly 8500 microhm-cm

So, as a thin-film, its resistivity is in between mercury and nichrome.

Of course, this is with the understanding that you accept all of the necessary assumptions and controls that go with the idea of electrical resistivity.

I would conjecture that unless you are changing the crystal structure from powder to thin-film, Tungsten (III) oxide should be conductive. As is Tungsten (IV) oxide.

 

[Ika]

Originally posted by: Tiamat
JACS article on Tungsten (III) Oxide thin films

Resistivity of the film was roughly 8500 microhm-cm

So, as a thin-film, its resistivity is in between mercury and nichrome.

I'm not sure if properties of tungsten (III) oxide would vary much from tungsten (VI) oxide... and I am assuming that means W2O3 is a conductor...

I know there isn't an absolute definition for "conductor" or "insulator", but this is for a genchem class, so it can't be that intense.

Let's put this question another way - if I measured a length of powder tungsten (VI) oxide (WO3), would resistance be zero or infinity?

 

[Tiamat]

Originally posted by: Aflac

Originally posted by: Tiamat
JACS article on Tungsten (III) Oxide thin films

Resistivity of the film was roughly 8500 microhm-cm

So, as a thin-film, its resistivity is in between mercury and nichrome.

I'm not sure if properties of tungsten (III) oxide would vary much from tungsten (VI) oxide... and I am assuming that means W2O3 is a conductor...

I know there isn't an absolute definition for "conductor" or "insulator", but this is for a genchem class, so it can't be that intense.

Let's put this question another way - if I measured a length of powder tungsten (VI) oxide (WO3), would resistance be zero or infinity?

Depends on the contact with the electrical probes. Its difficult to get good contact with powders and the multimeter probes as there is tons of air in the pores of the powder which make it very difficult to obtain any electrical measurement.

Given what I have read, which is not enough, I would hypothesize that the material conducts electricity. I have not found sources which show that it's conductivity would be comparable to, say, rubber, teflon, or fused quartz. Sources (as minimal as they are) seem to point to comparisons with nichrome, mercury, etc. Not excellent conductors, but conductors nonetheless.

Tungsten (VI) oxide could be tricky as the wikipedia page notes that its crystal structure is different depending on temperature. Assuming room temperature, you have monoclinic, but if you have a cold room, it could be triclinic.


If you have access to a voltage source, current measure unit, simply sweeping voltage while measuring the current should tell you what you need to know. If the trend follows ohm's law (linear increasing current with increasing voltage), you have a conductor. If the trend is exponential, or exponential, you have semiconductor-like properties. Obviously, if the trend is no increasing current measured with swept voltage, the material behaves like an insulator in the range of your swept voltage.

 

[NoShangriLa]

WO3 semiconductor powder

US Patent 6617190 - A-WO3-gate ISFET devices and method of making the same

 

[Ika]

Originally posted by: Tiamat

Depends on the contact with the electrical probes. Its difficult to get good contact with powders and the multimeter probes as there is tons of air in the pores of the powder which make it very difficult to obtain any electrical measurement.

Thanks; from that, I'll assume it's an insulator. Given that we were using pieces of copper wire stuffed in the ends of a cappillary tube and some crappy ohmmeters, it's probably going to be assumed that we would've gotten a measured resistance of infinity.

 

[Tiamat]

Originally posted by: Aflac

Originally posted by: Tiamat

Depends on the contact with the electrical probes. Its difficult to get good contact with powders and the multimeter probes as there is tons of air in the pores of the powder which make it very difficult to obtain any electrical measurement.

Thanks; from that, I'll assume it's an insulator. Given that we were using pieces of copper wire stuffed in the ends of a cappillary tube and some crappy ohmmeters, it's probably going to be assumed that we would've gotten a measured resistance of infinity.

Just be careful with your wording. The material itself may not be an insulator. Air certainly is, that is, until electrical breakdown. Given enough voltage, barriers can be crossed and current will flow.

I'd say that with the present testing, the WO3 powder/air mixture seemed to measure as electrical insulator. Note that it was not possible to ensure that a great WO3/Cu/WO3 connection was able to be made due to the powder nature and that this could have lead to the results as you measured.

Remember, your measurements are *never* wrong, it is the assumptions you make about the experiment and your conclusions based on those assumptions that could be wrong. By padding your conclusions and criticizing all the assumptions you make, as I noted, you open the door for further study in the event the measurements were "unexpected".

 

[NoShangriLa]

Originally posted by: Aflac

Originally posted by: Tiamat

Depends on the contact with the electrical probes. Its difficult to get good contact with powders and the multimeter probes as there is tons of air in the pores of the powder which make it very difficult to obtain any electrical measurement.

Thanks; from that, I'll assume it's an insulator. Given that we were using pieces of copper wire stuffed in the ends of a cappillary tube and some crappy ohmmeters, it's probably going to be assumed that we would've gotten a measured resistance of infinity.

WO3 is an insulator at low temperatures and a semiconductor at high temperatures.

 

[Tiamat]

Originally posted by: NoShangriLa

Originally posted by: Aflac

Originally posted by: Tiamat

Depends on the contact with the electrical probes. Its difficult to get good contact with powders and the multimeter probes as there is tons of air in the pores of the powder which make it very difficult to obtain any electrical measurement.

Thanks; from that, I'll assume it's an insulator. Given that we were using pieces of copper wire stuffed in the ends of a cappillary tube and some crappy ohmmeters, it's probably going to be assumed that we would've gotten a measured resistance of infinity.

WO3 is an insulator at low temperatures and a semiconductor at high temperatures.

If that is true, it goes with my previous notion that the crystal structure makes a difference in its electrical conductivity. Nice!