DOE OSTI2020
Sr3CaSn16 crystallizes in the orthorhombic Imm2 space group. The structure is three-dimensional. there are two inequivalent Sr sites. In the first Sr site, Sr is bonded in a 11-coordinate geometry to thirteen Sn atoms. There are a spread of Sr–Sn bond distances ranging from 3.47–3.66 Å. In the second Sr site, Sr is bonded in a 11-coordinate geometry to thirteen Sn atoms. There are a spread of Sr–Sn bond distances ranging from 3.47–3.68 Å. Ca is bonded in a 11-coordinate geometry to thirteen Sn atoms. There are a spread of Ca–Sn bond distances ranging from 3.44–3.63 Å. There are nine inequivalent Sn sites. In the first Sn site, Sn is bonded in a 3-coordinate geometry to three Sr and eight Sn atoms. There are four shorter (3.35 Å) and four longer (3.36 Å) Sn–Sn bond lengths. In the second Sn site, Sn is bonded in a 3-coordinate geometry to two equivalent Sr, one Ca, and eight Sn atoms. There are four shorter (3.34 Å) and four longer (3.37 Å) Sn–Sn bond lengths. In the third Sn site, Sn is bonded in a 3-coordinate geometry to two Sr, one Ca, and eight Sn atoms. There are a spread of Sn–Sn bond distances ranging from 3.34–3.36 Å. In the fourth Sn site, Sn is bonded in a 2-coordinate geometry to two equivalent Sr, one Ca, and six Sn atoms. There are a spread of Sn–Sn bond distances ranging from 2.94–3.44 Å. In the fifth Sn site, Sn is bonded in a 2-coordinate geometry to three Sr and six Sn atoms. There are a spread of Sn–Sn bond distances ranging from 2.96–3.44 Å. In the sixth Sn site, Sn is bonded in a 2-coordinate geometry to one Sr, two equivalent Ca, and six Sn atoms. There are one shorter (2.98 Å) and one longer (3.38 Å) Sn–Sn bond lengths. In the seventh Sn site, Sn is bonded in a 2-coordinate geometry to three Sr and six Sn atoms. The Sn–Sn bond length is 3.42 Å. In the eighth Sn site, Sn is bonded in a 4-coordinate geometry to two equivalent Sr, two equivalent Ca, and six Sn atoms. In the ninth Sn site, Sn is bonded in a 4-coordinate geometry to four Sr and six Sn atoms.