<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019e1b90-22b0-776e-bd93-295dd15ded4c,g:9cd508e7-b935-4815-8054-e5818201f69f-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:avtr="http://us.avtr.com/20260630" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2024-01-31" attributeFormDefault="unqualified" elementFormDefault="qualified" targetNamespace="http://us.avtr.com/20260630">
  <xs:import namespace="http://fasb.org/srt/2025" schemaLocation="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd"/>
  <xs:import namespace="http://fasb.org/us-gaap/2025" schemaLocation="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>
  <xs:import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/country/2025" schemaLocation="https://xbrl.sec.gov/country/2025/country-2025.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/currency/2025" schemaLocation="https://xbrl.sec.gov/currency/2025/currency-2025.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/dei/2025" schemaLocation="https://xbrl.sec.gov/dei/2025/dei-2025.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/ecd/2025" schemaLocation="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd"/>
  <xs:import namespace="http://xbrl.sec.gov/stpr/2025" schemaLocation="https://xbrl.sec.gov/stpr/2025/stpr-2025.xsd"/>
  <xs:annotation>
    <xs:appinfo>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="avtr-20260630_pre.xml" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="avtr-20260630_def.xml" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="avtr-20260630_lab.xml" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:type="simple"/>
      <link:linkbaseRef xmlns:xlink="http://www.w3.org/1999/xlink" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:href="avtr-20260630_cal.xml" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:type="simple"/>
      <link:roleType id="Documentandentityinformation" roleURI="http://us.avtr.com/role/Documentandentityinformation">
        <link:definition>0000001 - Document - Document and entity information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Unauditedcondensedconsolidatedbalancesheets" roleURI="http://us.avtr.com/role/Unauditedcondensedconsolidatedbalancesheets">
        <link:definition>9952151 - Statement - Unaudited condensed consolidated balance sheets</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="UnauditedcondensedconsolidatedbalancesheetsParenthetical" roleURI="http://us.avtr.com/role/UnauditedcondensedconsolidatedbalancesheetsParenthetical">
        <link:definition>9952152 - Statement - Unaudited condensed consolidated balance sheets (Parenthetical)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Unauditedcondensedconsolidatedstatementsofoperations" roleURI="http://us.avtr.com/role/Unauditedcondensedconsolidatedstatementsofoperations">
        <link:definition>9952153 - Statement - Unaudited condensed consolidated statements of operations</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Unauditedcondensedconsolidatedstatementsofcomprehensiveincomeorloss" roleURI="http://us.avtr.com/role/Unauditedcondensedconsolidatedstatementsofcomprehensiveincomeorloss">
        <link:definition>9952154 - Statement - Unaudited condensed consolidated statements of comprehensive income or loss</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Unauditedcondensedconsolidatedstatementsofstockholdersequityordeficitshares" roleURI="http://us.avtr.com/role/Unauditedcondensedconsolidatedstatementsofstockholdersequityordeficitshares">
        <link:definition>9952155 - Statement - Unaudited condensed consolidated statements of stockholders' equity or deficit - shares</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Unauditedcondensedconsolidatedstatementsofstockholdersequityamounts" roleURI="http://us.avtr.com/role/Unauditedcondensedconsolidatedstatementsofstockholdersequityamounts">
        <link:definition>9952156 - Statement - Unaudited condensed consolidated statements of stockholders' equity - amounts</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Unauditedcondensedconsolidatedstatementsofcashflows" roleURI="http://us.avtr.com/role/Unauditedcondensedconsolidatedstatementsofcashflows">
        <link:definition>9952157 - Statement - Unaudited condensed consolidated statements of cash flows</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Natureofoperationsandpresentationoffinancialstatements" roleURI="http://us.avtr.com/role/Natureofoperationsandpresentationoffinancialstatements">
        <link:definition>9952158 - Disclosure - Nature of operations and presentation of financial statements</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Newaccountingstandards" roleURI="http://us.avtr.com/role/Newaccountingstandards">
        <link:definition>9952159 - Disclosure - New accounting standards</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Earningspershare" roleURI="http://us.avtr.com/role/Earningspershare">
        <link:definition>9952160 - Disclosure - Earnings per share</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Segmentfinancialinformation" roleURI="http://us.avtr.com/role/Segmentfinancialinformation">
        <link:definition>9952161 - Disclosure - Segment financial information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Supplementaldisclosuresofcashflowinformation" roleURI="http://us.avtr.com/role/Supplementaldisclosuresofcashflowinformation">
        <link:definition>9952162 - Disclosure - Supplemental disclosures of cash flow information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Inventory" roleURI="http://us.avtr.com/role/Inventory">
        <link:definition>9952163 - Disclosure - Inventory</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Goodwillandotherintangibleassets" roleURI="http://us.avtr.com/role/Goodwillandotherintangibleassets">
        <link:definition>9952164 - Disclosure - Goodwill and other intangible assets</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Commitmentsandcontingencies" roleURI="http://us.avtr.com/role/Commitmentsandcontingencies">
        <link:definition>9952165 - Disclosure - Commitments and contingencies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Debt" roleURI="http://us.avtr.com/role/Debt">
        <link:definition>9952166 - Disclosure - Debt</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Accumulatedothercomprehensiveincomeorloss" roleURI="http://us.avtr.com/role/Accumulatedothercomprehensiveincomeorloss">
        <link:definition>9952167 - Disclosure - Accumulated other comprehensive income or loss</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Stockbasedcompensation" roleURI="http://us.avtr.com/role/Stockbasedcompensation">
        <link:definition>9952168 - Disclosure - Stock-based compensation</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Otherincomeorexpensenet" roleURI="http://us.avtr.com/role/Otherincomeorexpensenet">
        <link:definition>9952169 - Disclosure - Other income or expense, net</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Incometaxes" roleURI="http://us.avtr.com/role/Incometaxes">
        <link:definition>9952170 - Disclosure - Income taxes</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Derivativeandhedgingactivities" roleURI="http://us.avtr.com/role/Derivativeandhedgingactivities">
        <link:definition>9952171 - Disclosure - Derivative and hedging activities</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="Financialinstrumentsandfairvaluemeasurements" roleURI="http://us.avtr.com/role/Financialinstrumentsandfairvaluemeasurements">
        <link:definition>9952172 - Disclosure - Financial instruments and fair value measurements</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NatureofoperationsandpresentationoffinancialstatementsPolicies" roleURI="http://us.avtr.com/role/NatureofoperationsandpresentationoffinancialstatementsPolicies">
        <link:definition>9955511 - Disclosure - Nature of operations and presentation of financial statements (Policies)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EarningspershareTables" roleURI="http://us.avtr.com/role/EarningspershareTables">
        <link:definition>9955512 - Disclosure - Earnings per share (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentfinancialinformationTables" roleURI="http://us.avtr.com/role/SegmentfinancialinformationTables">
        <link:definition>9955513 - Disclosure - Segment financial information (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SupplementaldisclosuresofcashflowinformationTables" roleURI="http://us.avtr.com/role/SupplementaldisclosuresofcashflowinformationTables">
        <link:definition>9955514 - Disclosure - Supplemental disclosures of cash flow information (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="InventoryTables" roleURI="http://us.avtr.com/role/InventoryTables">
        <link:definition>9955515 - Disclosure - Inventory (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandotherintangibleassetsTables" roleURI="http://us.avtr.com/role/GoodwillandotherintangibleassetsTables">
        <link:definition>9955516 - Disclosure - Goodwill and other intangible assets (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtTables" roleURI="http://us.avtr.com/role/DebtTables">
        <link:definition>9955517 - Disclosure - Debt (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccumulatedothercomprehensiveincomeorlossTables" roleURI="http://us.avtr.com/role/AccumulatedothercomprehensiveincomeorlossTables">
        <link:definition>9955518 - Disclosure - Accumulated other comprehensive income or loss (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockbasedcompensationTables" roleURI="http://us.avtr.com/role/StockbasedcompensationTables">
        <link:definition>9955519 - Disclosure - Stock-based compensation (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OtherincomeorexpensenetTables" roleURI="http://us.avtr.com/role/OtherincomeorexpensenetTables">
        <link:definition>9955520 - Disclosure - Other income or expense, net (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncometaxesTables" roleURI="http://us.avtr.com/role/IncometaxesTables">
        <link:definition>9955521 - Disclosure - Income taxes (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DerivativeandhedgingactivitiesTables" roleURI="http://us.avtr.com/role/DerivativeandhedgingactivitiesTables">
        <link:definition>9955522 - Disclosure - Derivative and hedging activities (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FinancialinstrumentsandfairvaluemeasurementsTables" roleURI="http://us.avtr.com/role/FinancialinstrumentsandfairvaluemeasurementsTables">
        <link:definition>9955523 - Disclosure - Financial instruments and fair value measurements (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="NatureofoperationsandpresentationoffinancialstatementsNarrativeDetails" roleURI="http://us.avtr.com/role/NatureofoperationsandpresentationoffinancialstatementsNarrativeDetails">
        <link:definition>9955524 - Disclosure - Nature of operations and presentation of financial statements - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EarningspersharereconciliationDetails" roleURI="http://us.avtr.com/role/EarningspersharereconciliationDetails">
        <link:definition>9955525 - Disclosure - Earnings per share - reconciliation (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="EarningspershareantidilutivesecuritiesDetails" roleURI="http://us.avtr.com/role/EarningspershareantidilutivesecuritiesDetails">
        <link:definition>9955526 - Disclosure - Earnings per share - antidilutive securities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentfinancialinformationAdditionalInformationDetails" roleURI="http://us.avtr.com/role/SegmentfinancialinformationAdditionalInformationDetails">
        <link:definition>9955527 - Disclosure - Segment financial information - Additional Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentfinancialinformationreportedsegmentsDetails" roleURI="http://us.avtr.com/role/SegmentfinancialinformationreportedsegmentsDetails">
        <link:definition>9955528 - Disclosure - Segment financial information - reported segments (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentfinancialinformationadjustedoperatingincomeDetails" roleURI="http://us.avtr.com/role/SegmentfinancialinformationadjustedoperatingincomeDetails">
        <link:definition>9955529 - Disclosure - Segment financial information - adjusted operating income (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentfinancialinformationdepreciationandamortizationDetails" roleURI="http://us.avtr.com/role/SegmentfinancialinformationdepreciationandamortizationDetails">
        <link:definition>9955530 - Disclosure - Segment financial information - depreciation and amortization (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentfinancialinformationreconciliationofreconciliationofnetincomeDetails" roleURI="http://us.avtr.com/role/SegmentfinancialinformationreconciliationofreconciliationofnetincomeDetails">
        <link:definition>9955531 - Disclosure - Segment financial information - reconciliation of reconciliation of net income (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SegmentfinancialinformationproductlinesDetails" roleURI="http://us.avtr.com/role/SegmentfinancialinformationproductlinesDetails">
        <link:definition>9955532 - Disclosure - Segment financial information - product lines (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="SupplementaldisclosuresofcashflowinformationDetails" roleURI="http://us.avtr.com/role/SupplementaldisclosuresofcashflowinformationDetails">
        <link:definition>9955533 - Disclosure - Supplemental disclosures of cash flow information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="InventoryDetails" roleURI="http://us.avtr.com/role/InventoryDetails">
        <link:definition>9955534 - Disclosure - Inventory (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandotherintangibleassetsGoodwillbysegmentDetails" roleURI="http://us.avtr.com/role/GoodwillandotherintangibleassetsGoodwillbysegmentDetails">
        <link:definition>9955535 - Disclosure - Goodwill and other intangible assets - Goodwill by segment (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandotherintangibleassetsNarrativeDetails" roleURI="http://us.avtr.com/role/GoodwillandotherintangibleassetsNarrativeDetails">
        <link:definition>9955536 - Disclosure - Goodwill and other intangible assets - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="GoodwillandotherintangibleassetsScheduleofOtherintangiblesDetails" roleURI="http://us.avtr.com/role/GoodwillandotherintangibleassetsScheduleofOtherintangiblesDetails">
        <link:definition>9955537 - Disclosure - Goodwill and other intangible assets - Schedule of Other intangibles (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="CommitmentsandcontingenciesDetails" roleURI="http://us.avtr.com/role/CommitmentsandcontingenciesDetails">
        <link:definition>9955538 - Disclosure - Commitments and contingencies (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtScheduleofinformationaboutdebtDetails" roleURI="http://us.avtr.com/role/DebtScheduleofinformationaboutdebtDetails">
        <link:definition>9955539 - Disclosure - Debt - Schedule of information about debt (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtScheduleofinformationaboutdebtDetails_1" roleURI="http://us.avtr.com/role/DebtScheduleofinformationaboutdebtDetails_1">
        <link:definition>9955539 - Disclosure - Debt - Schedule of information about debt (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DebtotherinformationDetails" roleURI="http://us.avtr.com/role/DebtotherinformationDetails">
        <link:definition>9955540 - Disclosure - Debt - other information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="AccumulatedothercomprehensiveincomeorlossDetails" roleURI="http://us.avtr.com/role/AccumulatedothercomprehensiveincomeorlossDetails">
        <link:definition>9955541 - Disclosure - Accumulated other comprehensive income or loss (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockbasedcompensationexpenseDetails" roleURI="http://us.avtr.com/role/StockbasedcompensationexpenseDetails">
        <link:definition>9955542 - Disclosure - Stock-based compensation - expense (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockbasedcompensationotherinformationDetails" roleURI="http://us.avtr.com/role/StockbasedcompensationotherinformationDetails">
        <link:definition>9955543 - Disclosure - Stock-based compensation - other information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockbasedcompensationstockoptionrollforwardinformationDetails" roleURI="http://us.avtr.com/role/StockbasedcompensationstockoptionrollforwardinformationDetails">
        <link:definition>9955544 - Disclosure - Stock-based compensation - stock option rollforward information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="StockbasedcompensationnonoptionawardrollforwardDetails" roleURI="http://us.avtr.com/role/StockbasedcompensationnonoptionawardrollforwardDetails">
        <link:definition>9955545 - Disclosure - Stock-based compensation - non-option award rollforward (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OtherincomeorexpensenetDetails" roleURI="http://us.avtr.com/role/OtherincomeorexpensenetDetails">
        <link:definition>9955546 - Disclosure - Other income or expense, net (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="OtherincomeorexpensenetNarrativeDetails" roleURI="http://us.avtr.com/role/OtherincomeorexpensenetNarrativeDetails">
        <link:definition>9955547 - Disclosure - Other income or expense, net - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="IncometaxesDetails" roleURI="http://us.avtr.com/role/IncometaxesDetails">
        <link:definition>9955548 - Disclosure - Income taxes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DerivativeandhedgingactivitiesNarrativeDetails" roleURI="http://us.avtr.com/role/DerivativeandhedgingactivitiesNarrativeDetails">
        <link:definition>9955549 - Disclosure - Derivative and hedging activities - Narrative (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DerivativeandhedgingactivitiesOutstandingInterestRateDerivativesDetails" roleURI="http://us.avtr.com/role/DerivativeandhedgingactivitiesOutstandingInterestRateDerivativesDetails">
        <link:definition>9955550 - Disclosure - Derivative and hedging activities - Outstanding Interest Rate Derivatives (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DerivativeandhedgingactivitiesEffectonAOCIDetails" roleURI="http://us.avtr.com/role/DerivativeandhedgingactivitiesEffectonAOCIDetails">
        <link:definition>9955551 - Disclosure - Derivative and hedging activities - Effect on AOCI (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DerivativeandhedgingactivitiesDerivativeInstrumentsClassificationonBalanceSheetDetails" roleURI="http://us.avtr.com/role/DerivativeandhedgingactivitiesDerivativeInstrumentsClassificationonBalanceSheetDetails">
        <link:definition>9955552 - Disclosure - Derivative and hedging activities - Derivative Instruments Classification on Balance Sheet (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="DerivativeandhedgingactivitiesGainLossonNetInvestmentHedgesDetails" roleURI="http://us.avtr.com/role/DerivativeandhedgingactivitiesGainLossonNetInvestmentHedgesDetails">
        <link:definition>9955553 - Disclosure - Derivative and hedging activities - Gain (Loss) on Net Investment Hedges (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType id="FinancialinstrumentsandfairvaluemeasurementsScheduleofgrossamountsandfairvaluesofdebtinstrumentsDetails" roleURI="http://us.avtr.com/role/FinancialinstrumentsandfairvaluemeasurementsScheduleofgrossamountsandfairvaluesofdebtinstrumentsDetails">
        <link:definition>9955554 - Disclosure - Financial instruments and fair value measurements - Schedule of gross amounts and fair values of debt instruments (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xs:appinfo>
  </xs:annotation>
  <xs:element id="avtr_NumberOfStockOptionExcisedAndOtherCommonStockTransactions" abstract="false" name="NumberOfStockOptionExcisedAndOtherCommonStockTransactions" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="avtr_StockOptionExcisedAndOtherCommonStockTransactions" abstract="false" name="StockOptionExcisedAndOtherCommonStockTransactions" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="avtr_ProvisionForAccountsReceivableAndInventory" abstract="false" name="ProvisionForAccountsReceivableAndInventory" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="avtr_PensionTerminationCharges" abstract="false" name="PensionTerminationCharges" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="avtr_BioscienceMedtechProductsSegmentMember" abstract="true" name="BioscienceMedtechProductsSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_VWRDistributionServicesSegmentMember" abstract="true" name="VWRDistributionServicesSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_AdjustedOperatingIncome" abstract="false" name="AdjustedOperatingIncome" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="avtr_AdjustedCostOfGoodsAndServicesSold" abstract="false" name="AdjustedCostOfGoodsAndServicesSold" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="avtr_AdjustedOperatingExpenses" abstract="false" name="AdjustedOperatingExpenses" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="avtr_AdjustedCostOfGoodsAndServicesSoldNonGAAPAdjustments" abstract="false" name="AdjustedCostOfGoodsAndServicesSoldNonGAAPAdjustments" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="avtr_AdjustedOperatingExpensesNonGAAPAdjustments" abstract="false" name="AdjustedOperatingExpensesNonGAAPAdjustments" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="avtr_BusinessExitCostsAndEmployeeSeveranceMember" abstract="true" name="BusinessExitCostsAndEmployeeSeveranceMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_ExternalAdvisorsMember" abstract="true" name="ExternalAdvisorsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_ProprietaryMaterialsAndConsumablesMember" abstract="true" name="ProprietaryMaterialsAndConsumablesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_ThirdPartyMaterialsAndConsumablesMember" abstract="true" name="ThirdPartyMaterialsAndConsumablesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_FiniteLivedIntangibleAssetsImpairedAccumulatedImpairmentLoss" abstract="false" name="FiniteLivedIntangibleAssetsImpairedAccumulatedImpairmentLoss" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="avtr_FinanceLeaseObligationsMember" abstract="true" name="FinanceLeaseObligationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_OtherDebtMember" abstract="true" name="OtherDebtMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_MediumTermNotes2Point50PercentEUROTermLoanB6Member" abstract="true" name="MediumTermNotes2Point50PercentEUROTermLoanB6Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_MediumTermNotes1Point50PercentEUROTermLoanMember" abstract="true" name="MediumTermNotes1Point50PercentEUROTermLoanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_MediumTermLoan3Point875PercentDueNovember212024Instrument1Member" abstract="true" name="MediumTermLoan3Point875PercentDueNovember212024Instrument1Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_MediumTermLoan3Point875PercentDueNovember212024Instrument2Member" abstract="true" name="MediumTermLoan3Point875PercentDueNovember212024Instrument2Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_SeniorUnsecuredNotes4Point625PercentDueJuly152028Member" abstract="true" name="SeniorUnsecuredNotes4Point625PercentDueJuly152028Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_TermLoanMatureInOctober2032Member" abstract="true" name="TermLoanMatureInOctober2032Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_TermLoanMatureInOctober2030Member" abstract="true" name="TermLoanMatureInOctober2030Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_AmendedRevolvingCreditFacilityMatureInOctober2030Member" abstract="true" name="AmendedRevolvingCreditFacilityMatureInOctober2030Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_EquityAwardMember" abstract="true" name="EquityAwardMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_OtherStockBasedAwardMember" abstract="true" name="OtherStockBasedAwardMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_LiabilityAwardMember" abstract="true" name="LiabilityAwardMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_ForeignCurrencyTransactionGainLossFromFinancingActivities" abstract="false" name="ForeignCurrencyTransactionGainLossFromFinancingActivities" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="avtr_PensionTerminationPurchaseOfAnnuityContracts" abstract="false" name="PensionTerminationPurchaseOfAnnuityContracts" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="avtr_IncomeTaxExpenseBenefitReorganization" abstract="false" name="IncomeTaxExpenseBenefitReorganization" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="avtr_ForeignCurrencyDenominatedDebtMember" abstract="true" name="ForeignCurrencyDenominatedDebtMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_CrossCurrencyInterestRateContractMaturingInApril2027Member" abstract="true" name="CrossCurrencyInterestRateContractMaturingInApril2027Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_CrossCurrencyInterestRateContractMaturingInApril2028Member" abstract="true" name="CrossCurrencyInterestRateContractMaturingInApril2028Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_CrossCurrencyInterestRateContractMaturingInApril2029Member" abstract="true" name="CrossCurrencyInterestRateContractMaturingInApril2029Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_ThreePointEightHundredAndSeventyFivePercentUnsecuredMemberMember" abstract="true" name="ThreePointEightHundredAndSeventyFivePercentUnsecuredMemberMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_SeniorUnsecuredNotes3Point875PercentDueJuly152028Member" abstract="true" name="SeniorUnsecuredNotes3Point875PercentDueJuly152028Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="avtr_DerivativesUsedInNetInvestmentHedgeGrossOfTax" abstract="false" name="DerivativesUsedInNetInvestmentHedgeGrossOfTax" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="avtr_DerivativeNotionalAmountSold" abstract="false" name="DerivativeNotionalAmountSold" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
