Which Element Forms X2O3 with Oxygen?

[cp255]

A piece of unidentified element X reacts with oxygen to form an ionic compound with the chemical formula X2O3. Which of the following elements is the most likely identity of X?

A) Ba
B) Cs
C) In
D) P
E) Zn

I am doing exam practice questions and I came across this. The correct answer is C. I don't really know why.

 

[cp255]

I think I figured it out. The charges wouldn't balance with Ba2+, Cs+, or Zn2+, and phosphorous is negative which just leaves In.

 

[epenguin]

A piece of unidentified element X reacts with oxygen to form an ionic compound with the chemical formula X2O3. Which of the following elements is the most likely identity of X?

A) Ba
B) Cs
C) In
D) P
E) Zn

I am doing exam practice questions and I came across this. The correct answer is C. I don't really know why.

I think I figured it out. The charges wouldn't balance with Ba2+, Cs+, or Zn2+, and phosphorous is negative which just leaves In.

C?

I thought well theoretically you can imagine such a molecule as C₂O₃ (structure like an epoxide) but if it exists it must be pretty obscure (that appears to be the situation) mainly on the basis I haven't heard of it but maybe someone has a better reason. They wouldn't be asking you about it.

It seems to me for the rest the question can have two answers, but In is OK.

 

[Borek]

C not as in element, but C as in ABCDE answers given

I admit to make the same mistake initially.

From what I remember C₂O₃ was never observed (although several strange carbon oxides, like C₃O₂, have been made).

 

[epenguin]

I said there was more than one right answer. However I was thinking of compounds, viz P₂O₃ but I now see the question specified ions not compounds, so that excludes P₂O₃ (as well as C₂O₃ )

I guess when I see X₂O₃, P comes to my mind much more easily than In.

But then I was quite struck when recently you said

Indium(I) iodide comes to mind.

I was thinking of asking your permission to put it in the 'favorite quotes' thread if you didn't mind.

Or has the chemistry of Indium become more important than it was? (I do know it is used on the touch screen I'm using right now (though not why) and that sources of it are running out.)

 

[Borek]

Selection of indium iodide was pretty random, that was just the first compound that come to my mind when I looked at the periodic table.