wyckoffs: - "c" - "c" - "c" - "c" - "a" - "c" - "c" - "c" - "c" - "a" - "d" - "c" - "b" - "a" - "d" - "c" - "b" - "d" - "c" - "d" - "c" - "d" - "a" - "d" - "d" - "d"