YbCH4SeO8C2NH5 crystallizes in the triclinic P-1 space group. The structure consists of four dimethylamine molecules inside a YbCH4SeO8 framework. In the YbCH4SeO8 framework, there are two inequivalent Yb sites. In the first Yb site, Yb(1) is bonded in a 8-coordinate geometry to one O(1), one O(12), one O(13), one O(15), one O(16), one O(2), one O(5), and one O(7) atom. The Yb(1)-O(1) bond length is 2.33 Å. The Yb(1)-O(12) bond length is 2.21 Å. The Yb(1)-O(13) bond length is 2.30 Å. The Yb(1)-O(15) bond length is 2.46 Å. The Yb(1)-O(16) bond length is 2.55 Å. The Yb(1)-O(2) bond length is 2.80 Å. The Yb(1)-O(5) bond length is 2.12 Å. The Yb(1)-O(7) bond length is 2.28 Å. In the second Yb site, Yb(2) is bonded in a 8-coordinate geometry to one O(1), one O(11), one O(14), one O(15), one O(16), one O(2), one O(6), and one O(8) atom. The Yb(2)-O(1) bond length is 2.80 Å. The Yb(2)-O(11) bond length is 2.22 Å. The Yb(2)-O(14) bond length is 2.30 Å. The Yb(2)-O(15) bond length is 2.55 Å. The Yb(2)-O(16) bond length is 2.46 Å. The Yb(2)-O(2) bond length is 2.33 Å. The Yb(2)-O(6) bond length is 2.12 Å. The Yb(2)-O(8) bond length is 2.28 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(13) and one O(15) atom. The C(1)-O(13) bond length is 1.28 Å. The C(1)-O(15) bond length is 1.27 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one O(14) and one O(16) atom. The C(2)-O(14) bond length is 1.28 Å. The C(2)-O(16) bond length is 1.27 Å. There are eight inequivalent H sites. In the first H site, H(1) is bonded in a distorted single-bond geometry to one O(1) and one O(14) atom. The H(1)-O(1) bond length is 1.01 Å. The H(1)-O(14) bond length is 1.67 Å. In the second H site, H(2) is bonded in a distorted single-bond geometry to one O(13) and one O(2) atom. The H(2)-O(13) bond length is 1.67 Å. The H(2)-O(2) bond length is 1.01 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(1) atom. The H(3)-O(1) bond length is 0.99 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(2) atom. The H(4)-O(2) bond length is 0.99 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(7) atom. The H(5)-O(7) bond length is 0.98 Å. In the sixth H site, H(6) is bonded in a single-bond geometry to one O(8) atom. The H(6)-O(8) bond length is 0.98 Å. In the seventh H site, H(7) is bonded in a single-bond geometry to one O(10) and one O(7) atom. The H(7)-O(10) bond length is 1.69 Å. The H(7)-O(7) bond length is 1.00 Å. In the eighth H site, H(8) is bonded in a single-bond geometry to one O(8) and one O(9) atom. The H(8)-O(8) bond length is 1.00 Å. The H(8)-O(9) bond length is 1.69 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a tetrahedral geometry to one O(11), one O(3), one O(5), and one O(9) atom. The Se(1)-O(11) bond length is 1.72 Å. The Se(1)-O(3) bond length is 1.64 Å. The Se(1)-O(5) bond length is 1.70 Å. The Se(1)-O(9) bond length is 1.65 Å. In the second Se site, Se(2) is bonded in a tetrahedral geometry to one O(10), one O(12), one O(4), and one O(6) atom. The Se(2)-O(10) bond length is 1.65 Å. The Se(2)-O(12) bond length is 1.72 Å. The Se(2)-O(4) bond length is 1.64 Å. The Se(2)-O(6) bond length is 1.70 Å. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted water-like geometry to one Yb(1), one Yb(2), one H(1), and one H(3) atom. In the second O site, O(2) is bonded in a distorted water-like geometry to one Yb(1), one Yb(2), one H(2), and one H(4) atom. In the third O site, O(3) is bonded in a single-bond geometry to one Se(1) atom. In the fourth O site, O(4) is bonded in a single-bond geometry to one Se(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Yb(1) and one Se(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Yb(2) and one Se(2) atom. In the seventh O site, O(7) is bonded in a distorted water-like geometry to one Yb(1), one H(5), and one H(7) atom. In the eighth O site, O(8) is bonded in a distorted water-like geometry to one Yb(2), one H(6), and one H(8) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one H(8) and one Se(1) atom. In the tenth O site, O(10) is bonded in a distorted bent 150 degrees geometry to one H(7) and one Se(2) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one Yb(2) and one Se(1) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one Yb(1) and one Se(2) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Yb(1), one C(1), and one H(2) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal planar geometry to one Yb(2), one C(2), and one H(1) atom. In the fifteenth O site, O(15) is bonded in a distorted single-bond geometry to one Yb(1), one Yb(2), and one C(1) atom. In the sixteenth O site, O(16) is bonded in a distorted single-bond geometry to one Yb(1), one Yb(2), and one C(2) atom. Linkers: 1 [O]C(=O)C([O])=O. Metal clusters: 4 [Yb]. The MOF has largest included sphere 1.55 A, density 3.40 g/cm3, surface area 1773.59 m2/g, accessible volume 0.05 cm3/g