Ms Clarke,31,died in hospital on Wednesday evening,succumbing to her injuries.
Rowan Baxter also died at the scene,reportedly from self-inflicted stab wounds.
Premier Annastacia Palaszczuk said the country had been"left shaken,appalled and desperately saddened"by the tragedy that unfolded in the suburbs of Brisbane on Wednesday.
"This unthinkable act of violence took the lives of three beautiful,innocent children as their mother – like thousands of other Queensland mums – left early yesterday to take her kids to school,"Ms Palaszczuk said.
"The grief being felt by the family and friends of this young woman and her children is beyond
description;my deepest sympathies go out to them."
Prime Minister Scott Morrison said the country was shocked at the family being"senselessly murdered".