The structure of IRMOF1. The labels C1, C2, etc., denote different crystallographic positions (see Table II). (a) A single cube fragment of the complete structure. Each corner of the cube is made up of a connector, and each side is made up of a linker. (b) Connector: it can be described as one central tetrahedron and four distorted tetrahedra; the labels and denote O1 atoms belonging to two different distorted tetrahedra. (c) Linker: reminiscent of the organic molecule 1,4 benzenedicarboxylate (BDC). In -IRMOF1, two different linkers are connected to each other by bridges.
Electronic properties of -IRMOF1 ( and Be). (a) Electronic density of states, (b) electronic band structure, and (c) partial electronic density of states of Zn-IRMOF1; (d) electronic density of states and (e) electronic band structure of Be-IRMOF1. For clarity, only the region near the band gap is shown. The top of the valence band and Fermi level are located at 0.0. The Fermi level is indicated by the dotted line.
Electronic properties of ( and Be). (a) Electronic densities of states of (black line) and Zn-IRMOF1 (red line); (b) electronic densities of states of (black line) and Be-IMOF1 (red line). For clarity, only the region near the band gap is shown. The Fermi level for ( and Be) is indicated by the black dotted line.
Structural parameters of -IRMOF1 (, Cd, Be, Mg, and Ca). The equilibrium lattice constant and bulk modulus were obtained by fitting the energy vs the volume curve to the Birch–Murnaghan equation of state (Ref. 15). represents the distance from the metal atom to its closer neighbor, which is always oxygen in the crystallographic position O1. We interpret the change in this distance as Zn is replaced by other atoms to represent differences in their atomic radii. represents the calculated difference in atomic radius relative to Zn (see text for an explanation).
Ab initio and experimental (in parenthesis) atomic positions in fractional coordinates for Zn-IRMOF1. Space group . The experimental values were taken from the desolvated form of Zn-IRMOF1 (Ref. 16).
Ab initio structural parameters of the linker for each -IRMOF1.
Ab initio structural parameters of the connector for each -IRMOF1. The variable stands for the volume of the connector assuming that it has an octahedral shape.
Electronic properties of -IRMOF1. Electronic band gap and bandwidth of the lower part of the conduction band. (For aiding the text explanation, some of the structural parameters of the connectors have been also collected in the last two columns.)
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