1) Provide explanations for the number of intense perchlorate Cl-O stretching vibrational modes observed in the IR of the following three silver(I) complexes. a) The perchlorate anion in Ag(NH3)2(ClO4) has a single intense Cl-O stretching vibrational mode observed by IR at 1170cm-1. b) The IR of Ag(NH3)ClO4 has three Cl-O stretching vibrational modes at 1220 cm-1,1130 cm-1and 920 cm-1 observed in the IR . c) The IR of AgClO4 has four Cl-O stretching vibrational modes at 1210 cm-1,1140 cm-1 , 1040 and 910 cm-1 observed in the IR . 2) The gas phase cobalt(II) free ion has a 4F ground term which in an octahedral ligand field splits into 4T1g (-0.6 ?o CI) , 4T2g(+0 .2 ?o) and 4A2g (+1,2 ?o ) electronic states. a) How many micro states are contained in the 4F ground term of gas phase cobalt(II) free ion and the4T2g electronic state for an octahedral cobalt(II) complex ? b) What is the ground state for a tetrahedral cobalt(II) complex ? c) Provide an explanation for the difference in effective magnetic moments between K2[CoCl4] (?eff(298K) = 3.9 ?) and K4[CoCl6] (?eff (298K)= 5.0?) . (? = electron Bohr Magneton) d) What are the ?o and CI values for an octahedral Co(II) complex that has ligand field transitions at ??1 =7,400cm-1 (4T2g ?4T1g) and ??2 =15,400cm-1 (4A2g ?4T1g) ? 3 Vanadium tetrachloride (VCl4 ) is a bright red colored liquid with a vapor pressure of 5×10-2 torr at 298K. a) Briefly discuss why the standard state of VCl4 is a liquid and VCl2 is an ioni
c solid? b) How many microstates are in the gas phase V4+ free ion ground term and the V4+ free ion ground J state ? c) How many microstates are present in the ground electron configuration and ground electronic state for VCl4 assuming tetrahedral symmetry ? d) State the Jahn Teller Theorem and briefly discuss whether or not VCl4(g) is expected to manifest a Jahn Teller effect . e) What is the expected orbital angular momentum in the ground state of VCl4(g) ? f) The molar magnetic susceptibility (?m) at 298K is +1130×10-6 cm3mol-1 . What is the effective magnetic moment for VCl4 at 298K and does this ?eff fulfill the expectations for VCl4 ground state in Td symmetry ? g) Use the electric dipole transition selection rules to show whether or not the ligand field ( d?d ) transition(s) for VCl4 are spin and orbitally allowed as pure electric dipole transitions assuming Td symmetry. h) Write down the irreducible representations for VCl4(g) translations , rotations and vibrations assuming Td symmetry. 3) Provide brief well focused responses to the following questions. a) Why is ?o for the [Cr(CN)6]3- anion very much larger than ?o for [CrCl6]3-? b) Qualitatively compare the expected ?eff (298K) values for the octahedral complex anions [CrCl6]3- and [Cr(CN)6]3- . c) The [CoCl4]2- anion is intensely blue colored and [CoCl6]4- is a lightly colored pink. d) Why is the method of descending symmetry needed to derive an mo diagram for acetylene (ethyne), but not needed for diazene((NH)2)?