Does deuterium peroxide exist? Wikipedia has no reference. Also, the sites for delivery of chemicals like "Pubchem" or "Chemspider" have no reference.
In my book, a preparation of $\ce{D2O2}$ is given,
$$\ce{K2S2O8 + 2D2O -> 2KDSO4 +D2O2}$$
If $\ce{D2O2}$ exist, what are its physical properties (structure and appearance etc.)?