The chemistry laboratory at the University of Bristol was evacuated after triacetone triperoxide (TATP) was "unintentionally formed".
Police, fire service and bomb disposal experts were called to the building following the incident on February 3.
No-one was injured and emergency services carried out a controlled explosion of the substance.
Emergency services were called in after a student accidentally made explosives during an experiment
The student was following a published literature method and the risk of TATP as a potential by-product had been identified during the risk assessment process
University of Bristol
TATP was used in bomb vests worn by militants in the terror attacks that killed 130 people in November 2015.
A spokesman for the University of Bristol said: "Following a full investigation, we can confirm that the chemical triacetone triperoxide (TATP) was unintentionally formed during a routine procedure carried out by a PhD student.
"The student was following a published literature method and the risk of TATP as a potential by-product had been identified during the risk assessment process.
The explosives were created as a side product of a well-document experiment procedure
"We have robust contingency plans in place to deal with incidents of this nature.
"As soon as the presence of TATP was identified, the student immediately notified those responsible for laboratory safety in the school.
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The responsible student immediately notified the right people
"A series of actions were then taken which resulted in the precautionary evacuation of the chemistry building and surrounding buildings and the controlled disposal of the substance by the emergency services."
The spokesman said the School of Chemistry risk assessment process is being reviewed to determine whether additional checks can be made.