DOE OSTI2020
Rb4Pb9 is Magnesium tetraboride-like structured and crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are five inequivalent Rb sites. In the first Rb site, Rb is bonded in a 7-coordinate geometry to seven Pb atoms. There are a spread of Rb–Pb bond distances ranging from 3.82–3.93 Å. In the second Rb site, Rb is bonded in a 8-coordinate geometry to eight Pb atoms. There are a spread of Rb–Pb bond distances ranging from 3.87–4.29 Å. In the third Rb site, Rb is bonded in a 8-coordinate geometry to eight Pb atoms. There are a spread of Rb–Pb bond distances ranging from 3.84–4.14 Å. In the fourth Rb site, Rb is bonded in a 7-coordinate geometry to seven Pb atoms. There are a spread of Rb–Pb bond distances ranging from 4.01–4.04 Å. In the fifth Rb site, Rb is bonded in a 7-coordinate geometry to eight Pb atoms. There are a spread of Rb–Pb bond distances ranging from 3.81–4.35 Å. There are twelve inequivalent Pb sites. In the first Pb site, Pb is bonded in a 8-coordinate geometry to four Rb and four Pb atoms. There are a spread of Pb–Pb bond distances ranging from 3.14–3.27 Å. In the second Pb site, Pb is bonded in a 1-coordinate geometry to three Rb and five Pb atoms. There are a spread of Pb–Pb bond distances ranging from 3.13–3.50 Å. In the third Pb site, Pb is bonded in a 1-coordinate geometry to three Rb and five Pb atoms. There are a spread of Pb–Pb bond distances ranging from 3.15–3.45 Å. In the fourth Pb site, Pb is bonded in a 8-coordinate geometry to four Rb and four Pb atoms. There are a spread of Pb–Pb bond distances ranging from 3.16–3.25 Å. In the fifth Pb site, Pb is bonded in a 6-coordinate geometry to three Rb and five Pb atoms. There are one shorter (3.14 Å) and two longer (3.53 Å) Pb–Pb bond lengths. In the sixth Pb site, Pb is bonded in a 2-coordinate geometry to four Rb and four Pb atoms. There are a spread of Pb–Pb bond distances ranging from 3.16–3.20 Å. In the seventh Pb site, Pb is bonded in a distorted body-centered cubic geometry to four Rb and four Pb atoms. In the eighth Pb site, Pb is bonded in a 9-coordinate geometry to four Rb and five Pb atoms. Both Pb–Pb bond lengths are 3.25 Å. In the ninth Pb site, Pb is bonded in a 7-coordinate geometry to three Rb and four Pb atoms. In the tenth Pb site, Pb is bonded in a 1-coordinate geometry to five Rb and four Pb atoms. Both Pb–Pb bond lengths are 3.16 Å. In the eleventh Pb site, Pb is bonded in a 7-coordinate geometry to three Rb and four Pb atoms. There are one shorter (3.22 Å) and one longer (3.23 Å) Pb–Pb bond lengths. In the twelfth Pb site, Pb is bonded in a 1-coordinate geometry to two Rb and five Pb atoms.