Ammonium dimolybdate

<p>Ammonium dimolybdate (ADM) is the inorganic compound with the formula (NH4)2Mo2O7. It is a white, water-soluble solid. ADM is an intermediate in the production of <a href="/facts/Molybdenum/RX6vp2bF">molybdenum</a> compounds from its ores.  Roasting typical ore produces crude molybdenum(VI) oxides, which can be extracted into aqueous <a href="/facts/Ammonia/MtLtJFtz">ammonia</a>, affording <a href="/facts/Ammonium_molybdate/cN9qnHkp">ammonium molybdate</a>.  Heating solutions of ammonium molybdate gives ADM.  Upon heating, solid ammonium dimolybdate decomposes to <a href="/facts/Molybdenum_trioxide/4QpFEqmg">molybdenum trioxide</a>:
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(NH4)2Mo2O7   →   2 MoO3  +  2 NH3  +  H2O
<p>In terms of its chemical structure, the anion is a polymeric consisting of distorted octahedral Mo centers linked by tetrahedral molybdate centers.  When prepared in the absence of water as its <a href="/facts/Tetrabutylammonium/thxACdb6">tetrabutylammonium</a> salt, dimolybdate adopts the centrosymmetric structure observed for dichromate.
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Ammonium dimolybdate open-in-new

Ammonium dimolybdate