noun
space group
Technical term in crystallography and mathematics; refers to the symmetry group of a crystal structure in three dimensions.
結晶構造は230種類の空間群のいずれかに分類される。
Crystal structures are classified into one of the 230 space groups.
点群 (point group) describes symmetry operations that leave at least one point fixed, while 空間群 includes translations and describes full three-dimensional crystal symmetry.
Compound of 空間 (space) and 群 (group), likely a calque from English 'space group' or German 'Raumgruppe'.