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  <xsd:element id="ato_RatioofTotalDebttoTotalCapital" name="RatioofTotalDebttoTotalCapital" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element id="ato_RegulatedSegmentsEffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" name="RegulatedSegmentsEffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="ato_RegulatoryAssetFutureRecoverablePensionCosts" name="RegulatoryAssetFutureRecoverablePensionCosts" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="ato_RegulatoryCostOfRemovalLiability" name="RegulatoryCostOfRemovalLiability" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ato_RegulatoryCostofServiceReserveMember" name="RegulatoryCostofServiceReserveMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ato_RegulatoryLiabilityExcessDeferredTax" name="RegulatoryLiabilityExcessDeferredTax" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ato_RequiredbyCovenantMember" name="RequiredbyCovenantMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ato_ScheduleOfExpectedDeferredGainsLossesRecognitionTableTextBlock" name="ScheduleOfExpectedDeferredGainsLossesRecognitionTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_ScheduleOfOperatingRevenuesAndPurchasedGasCostBySegmentTable" name="ScheduleOfOperatingRevenuesAndPurchasedGasCostBySegmentTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ato_ScheduleOfOtherFairValueMeasuresTableTextBlock" name="ScheduleOfOtherFairValueMeasuresTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="ato_ScheduleOfRegulatoryAssetsAndLiabilitiesTableTextBlock" name="ScheduleOfRegulatoryAssetsAndLiabilitiesTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_ScheduleofOtherComprehensiveIncomeLossCashFlowHedgesLineItems" name="ScheduleofOtherComprehensiveIncomeLossCashFlowHedgesLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_ScheduleofOtherComprehensiveIncomeLossCashFlowHedgesTable" name="ScheduleofOtherComprehensiveIncomeLossCashFlowHedgesTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_ScheduleofOtherComprehensiveIncomeLossTaxCashFlowHedgesLineItems" name="ScheduleofOtherComprehensiveIncomeLossTaxCashFlowHedgesLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_ScheduleofOtherComprehensiveIncomeLossTaxCashFlowHedgesTable" name="ScheduleofOtherComprehensiveIncomeLossTaxCashFlowHedgesTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_SegmentReportingInformationBalanceSheetAbstract" name="SegmentReportingInformationBalanceSheetAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="ato_SelfInsuredRetentionExpense" name="SelfInsuredRetentionExpense" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="ato_TaxCreditCarryforwardExpectedRefundDate" name="TaxCreditCarryforwardExpectedRefundDate" nillable="true" substitutionGroup="xbrli:item" type="xbrli:dateItemType" xbrli:periodType="duration" />
  <xsd:element id="ato_TaxCreditCarryforwardFederalTaxEffects" name="TaxCreditCarryforwardFederalTaxEffects" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ato_TermLoanAgreementAmountOutstanding" name="TermLoanAgreementAmountOutstanding" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="ato_TermLoanAgreementMaximumBorrowingCapacity" name="TermLoanAgreementMaximumBorrowingCapacity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="ato_ThereafterMember" name="ThereafterMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="ato_UndistributedEarningsFromDiscontinuedOperationsAllocatedToParticipatingSecurities" name="UndistributedEarningsFromDiscontinuedOperationsAllocatedToParticipatingSecurities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_UnsecuredDebenturesDue2028Member" name="UnsecuredDebenturesDue2028Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_UnsecuredLoanAgreementMember" name="UnsecuredLoanAgreementMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_UnsecuredRevolvingCreditNoteMember" name="UnsecuredRevolvingCreditNoteMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_UnsecuredSeniorNotesDue2019Member" name="UnsecuredSeniorNotesDue2019Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_UnsecuredSeniorNotesDue2027Member" name="UnsecuredSeniorNotesDue2027Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_UnsecuredSeniorNotesDue2034Member" name="UnsecuredSeniorNotesDue2034Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_UnsecuredSeniorNotesDue2041Member" name="UnsecuredSeniorNotesDue2041Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_UnsecuredSeniorNotesDue2043Member" name="UnsecuredSeniorNotesDue2043Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="ato_UnsecuredSeniorNotesDue2044Member" name="UnsecuredSeniorNotesDue2044Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
</xsd:schema>
