<?xml version="1.0" encoding="utf-8"?><mads xmlns="http://www.loc.gov/mads/" xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.loc.gov/mads/
mads.xsd"><authority><topic authority="http://AATesaurus.cultura.gencat.cat/aat/getty_en">ammonium oxalate</topic></authority><related type="broader"><topic>oxalate</topic></related><variant type="other"><topic>oxalate, ammonium</topic></variant> <note xml:lang="en"><![CDATA[ Refers to oxalate with ammonia commercially produced as colorless crystals used for dyeing textiles and in other applications. In conservation, ammonium oxalate in solution is used as a treatment for calcium carbonate based surfaces (such as limestones, marbles, historical wall paintings). It forms a protective layer of calcium oxalate on surfaces through chemical reaction.   ]]></note></mads>