<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31375540</termId><termName>ammonium oxalate</termName><termType>PT</termType><termNote><![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.   ]]></termNote><termCreatedDate>2026-03-30 20:41:17</termCreatedDate><relation><relationType>UF</relationType><termId>31375541</termId><termName>oxalate, ammonium</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31344824</termId><termName>oxalate</termName><termType>PT</termType></relation></term>  </Zthes>