Chapter 4, Problem 4.32P

White elemental phosphorus consists of tetrahedral ${\text{P}}_{\text{4}}$ molecules and is an importantsource of phosphorus for synthesis. In contrast, tetrahedral ${\text{As}}_{\text{4}}$ (yellow arsenic) is unstable, anddecomposes to a grey As allotrope with a sheet structure. However, ${\text{AsP}}_{\text{3}}$ , previously onlyobserved at high temperature in the gas phase, has been isolated at ambient temperature as awhite solid, where an As atom replaces one vertex of the tetrahedron.
a. The Raman spectrum of ${\text{AsP}}_{\text{3}}$ , shown next, exhibits four absorptions. Is this consistentwith the proposed structure? (Facile Synthesis of ${\text{AsP}}_{\text{3}}$ , Brandi M. Cossairt, Mariam-CélineDiawara, Christopher C. Cummins. © 2009. The American Association for theAdvancement of Science. Reprinted with permission from AAAS.)

b. If ${\text{As}}_{\text{2}}{\text{P}}_{\text{2}}$ is ever isolated as a pure substance, how many Raman absorptions would beexpected? (Reference: B. M. Cossairt, C. C. Cummins, J. Am. Chem. Soc. 2009, 131,15501.)
c. Could a pure sample of ${\text{P}}_{\text{4}}$ be distinguished from pure ${\text{AsP}}_{\text{3}}$ simply on the basis of thenumber of Raman absorptions? Explain.