6
$\begingroup$

What do $\ce{diH_2O, dH_2O}$, and $\ce{DI H_2O}$ mean?

I'm not asking for a description of deionized water and distilled water. I'm asking what the three abbreviations/formulas mean.

In other words, I'm asking someone to fill in the blanks below.

  • $\ce{diH_2O = \_\_\_\_\_}$
  • $\ce{dH_2O = \_\_\_\_\_}$
  • $\ce{DI H_2O = \_\_\_\_\_}$
$\endgroup$
  • 5
    $\begingroup$ * diH2O = deionized water * dH2O = distilled water * DI H2O = deionized water $\endgroup$ – Curt F. Feb 17 '16 at 5:01
  • $\begingroup$ Thanks @CurtF. I found a book that referred to diH2O as distilled, not deionized water. Is there no commonly accepted standard, or is this just a fluke reference I found? books.google.com/… $\endgroup$ – kdauria Feb 17 '16 at 5:06
  • 3
    $\begingroup$ I don't think there is a commonly accepted standard. If I had to guess, I'd say more often than not di$\ce{H2O}$ is used to mean deionized water, but I've nothing but my own experience to base that on. Sorry for the lack of references. Also, ddH2O is a common abbreviation that used to mean "double-distilled water" but now is used to refer to highly pure water produced by laboratory purification systems such as those from milliQ or similar. $\endgroup$ – Curt F. Feb 17 '16 at 5:11
  • 2
    $\begingroup$ As Curt F. indicates, what they stand for and what they are in practice are two different things. In practice, the four abbreviations "mean" the same thing: high purity water. If there's some practical difference between distilled, double-distilled and deionized water that means one is suitable and the other is not, you'll normally get a more extensive description of the minimal performance and purity characteristics necessary for the application. $\endgroup$ – R.M. Sep 26 '16 at 16:21
  • 2
    $\begingroup$ A meta discussion about the edits to this question can be found here: meta.chemistry.stackexchange.com/q/3467/7951 $\endgroup$ – Loong Dec 3 '16 at 1:36
7
$\begingroup$

I don't think there is a commonly accepted standard. If I had to guess, I'd say more often than not $\mathrm{di}\ce{H2O}$ is used to mean deionized water, but I've nothing but my own experience to base that on. Sorry for the lack of references. Also, $\mathrm{dd}\ce{H2O}$ is a common abbreviation that used to mean "double-distilled water" but now is used to refer to highly pure water produced by laboratory purification systems such as those from Milli-Q or similar.

  • $\mathrm{DI}\ce{H2O}$ = deionized water
  • $\mathrm{di}\ce{H2O}$ = deionized water
    • Such water is often available from centralized water purification systems in buildings that host many chemical laboratories. It isn't as pure as "$\mathrm{dd}\ce{H2O}$" (see below) but is subtanstially more pure than tap water.
  • $\mathrm{d}\ce{H2O}$ = distilled water
  • $\mathrm{dd}\ce{H2O}$ = doubly distilled water
  • $\mathrm{mq}\ce{H2O}$ = Milli-Q water
    • The brand name of a popular type of water purifier that gives purity similar to $\mathrm{dd}\ce{H2O}$
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.