Early in 2009, Christopher Cummins’ group at MIT reported (in Science) the synthesis of AsP3, a compound that had never been isolated at room temperature. Later that year, a full article was published in JACS comparing the properties and reactivity of AsP3 to those of its molecular cousins, P4 and As4. The longer article is full of possibilities for discussion in inorganic chemistry courses, with topics including periodic trends, NMR, vibrational spectroscopy, electrochemistry, molecular orbital theory, and coordination chemistry.
After reading and discussing this paper, a student should be able to:
• recognize the general names used for groups 15, 16, and 17
• derive the expected number of Raman resonances for the AsP3 and P4 molecules
• outline the trend observed in P–P vs As–P bond strength
• compare the reactivity of P4 and AsP3 in at least one example and make predictions regarding As2P2 and As3P reactivity
This learning object was developed as one of five journal article discussions included in a small (5 student) senior-level inorganic course in the spring of 2010. This course is the only inorganic course (aside from a separate inorganic laboratory) offered in our curriculum.
The literature discussions were interspersed throughout the semester. This journal discussion was the final one in the semester, and we discussed questions 1-4 as a group before each individual presented the results of the reactivity studies they had chosen (question 5). Student presentations were informal; it was a good opportunity for them to learn how to condense information.
The students’ written answers to the questions and presentations of the questions were graded.
Because we discussed this article at the end of the semester, the stretching mode analysis was not fresh in the students’ minds. They appreciated the chance to review earlier portions of the course.