The novel selenostannate(IV anion, Sn4Se104-, has been obtained by extracting the ternary alloy KSn0.67Se1.93 in ethylenediamine (en) and liquid NH3 in the presence of 2,2,2-crypt (4,7,13, 16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) and characterized in solution by Se-77 and Sn-119 NMR spectroscopy and in the solid state by X-ray crystallography and Raman spectroscopy. The scalar couplings, (1)J(Sn-119-Se-77) and (2)J([Sn-119-Sn-117), have been determined and compared with those of related systems. The salt, (2,2,2-crypt-K+)(4)Sn4Se104-, crystallizes in the triclinic system, space group , with Z = 2 and a = 14.769(2) Angstrom, b = 15.580(1) Angstrom, c = 26.275(4) Angstrom, alpha = 79.19(1)Angstrom, beta = 85.65(1)degrees, and gamma = 85.870(8)degrees at 24 degrees C. The solid state and solution anion geometry is of the adamantanoid type where the Sn-IV atoms occupy the bridgehead positions and the Se atoms occupy the bridging and terminal sites. The terminal [average, 2.425(2) Angstrom] and bridging [average, 2.548(2) Angstrom] Sn-Se bond distances were found to correlate with their respective (1)J(Sn-119-Se-117) coupling constants. The Raman spectrum of the Sn4Se104- anion has been assigned and compared to those of related adamantanoid systems and SnSe44-.