Which of the follwing molecular species does not exist?

Options

A. `He_(2)`
B. `He_(2)^(+)`
C. `HeH^(+)`
D. `HeH^(2+)`

Answer

1

Explanation

The noble gases were isolated and discovered because of their lack of reactivity. For a long time it was thought that they really were chemically inert. Several molecular ions such as `He_(2)^(+), HeH^(+), HeH^(2+)` and `Ar_(2)^(+)` are formed in discharge tubes under high energy conditions. However they only survive momentarily and are detected spectroscopically. Neutral molecules such as `He_(2)` (having zero bond order) are unstable.